<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e1d71-48bb-7fc1-a56f-dae4821d785d,g:b2fb955c-bb27-4c06-846e-27481b754fdb-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.3dsystems.com/role/CondensedConsolidatedStatementsofOperationsUnaudited" xlink:type="simple" xlink:href="ddd-20260630.xsd#CondensedConsolidatedStatementsofOperationsUnaudited"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/CondensedConsolidatedStatementsofOperationsUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e1d71-4969-75f9-9aba-9aca0dc7eafb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_StatementTable_019e1d71-4969-75f9-9aba-9aca0dc7eafb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019e1d71-4969-7b82-879b-f591de67f7b7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e1d71-4969-75f9-9aba-9aca0dc7eafb" xlink:to="loc_srt_ProductOrServiceAxis_019e1d71-4969-7b82-879b-f591de67f7b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e1d71-4969-7b82-879b-f591de67f7b7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019e1d71-4969-7b82-879b-f591de67f7b7" xlink:to="loc_srt_ProductsAndServicesDomain_019e1d71-4969-7b82-879b-f591de67f7b7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019e1d71-4969-70c3-a6ec-cbd3b93703da" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019e1d71-4969-7b82-879b-f591de67f7b7" xlink:to="loc_srt_ProductsAndServicesDomain_019e1d71-4969-70c3-a6ec-cbd3b93703da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_019e1d71-4969-7815-865c-9eb336874761" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e1d71-4969-70c3-a6ec-cbd3b93703da" xlink:to="loc_us-gaap_ProductMember_019e1d71-4969-7815-865c-9eb336874761" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_019e1d71-4969-74f7-a2bd-4a92d7b69546" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019e1d71-4969-70c3-a6ec-cbd3b93703da" xlink:to="loc_us-gaap_ServiceMember_019e1d71-4969-74f7-a2bd-4a92d7b69546" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019e1d71-4969-7104-9601-31efc2a83d44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_RevenuesAbstract_019e1d71-4969-7104-9601-31efc2a83d44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-74ba-9c36-ac73ae89b407" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019e1d71-4969-7104-9601-31efc2a83d44" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-74ba-9c36-ac73ae89b407" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4969-7c8c-805b-07af04c477be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSoldAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4969-7c8c-805b-07af04c477be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-751a-aead-3457eed3c218" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4969-7c8c-805b-07af04c477be" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-751a-aead-3457eed3c218" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e1d71-4969-77d5-b1cd-0aab458d258a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_GrossProfit_019e1d71-4969-77d5-b1cd-0aab458d258a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019e1d71-4969-7c31-aa8a-87d38da58e4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019e1d71-4969-7c31-aa8a-87d38da58e4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e1d71-4969-76a0-95a0-caaf32364227" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019e1d71-4969-7c31-aa8a-87d38da58e4c" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e1d71-4969-76a0-95a0-caaf32364227" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019e1d71-4969-7cea-a1e7-ab6b42238f27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019e1d71-4969-7c31-aa8a-87d38da58e4c" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019e1d71-4969-7cea-a1e7-ab6b42238f27" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019e1d71-4969-7c88-980c-d0f0a3b70bb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019e1d71-4969-7c31-aa8a-87d38da58e4c" xlink:to="loc_us-gaap_OperatingExpenses_019e1d71-4969-7c88-980c-d0f0a3b70bb2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019e1d71-4969-7bb2-a8f3-32c55d5a3b74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_OperatingIncomeLoss_019e1d71-4969-7bb2-a8f3-32c55d5a3b74" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e1d71-4969-7e13-8e47-6746c6e19268" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e1d71-4969-7e13-8e47-6746c6e19268" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_019e1d71-4969-7f26-a7df-055f00d503f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_InvestmentIncomeInterest_019e1d71-4969-7f26-a7df-055f00d503f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInvestmentExpense_019e1d71-4969-7122-86d5-4f8d813c4f72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInvestmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_InvestmentIncomeInvestmentExpense_019e1d71-4969-7122-86d5-4f8d813c4f72" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_019f6a3c-eaf0-71f3-8a38-101d23a9a5dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_019f6a3c-eaf0-71f3-8a38-101d23a9a5dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e1d71-4969-72c3-b41a-f78af57ebb7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e1d71-4969-72c3-b41a-f78af57ebb7e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_019e1d71-4969-7006-89f4-b94594ffa085" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_019e1d71-4969-7f56-b55b-577579959d33" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_019e1d71-4969-7006-89f4-b94594ffa085" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019e1d71-4969-7e95-a893-a753591e9cf8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_019e1d71-4969-7e95-a893-a753591e9cf8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019e1d71-4969-7ef6-9b73-dead07c35088" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019e1d71-4969-7ef6-9b73-dead07c35088" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e1d71-4969-7d1a-8777-608d346e1d6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e1d71-4969-7d1a-8777-608d346e1d6d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019e1d71-4969-76ea-9889-493888b6416a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_ProfitLoss_019e1d71-4969-76ea-9889-493888b6416a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019e1d71-4969-77dc-8667-ca97721825e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019e1d71-4969-77dc-8667-ca97721825e1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e1d71-4969-7b38-9446-6c75fabf8759" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_NetIncomeLoss_019e1d71-4969-7b38-9446-6c75fabf8759" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019e1d71-4969-7406-8eb1-08661c9a1700" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019e1d71-4969-7406-8eb1-08661c9a1700" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019e1d71-4969-7e01-b832-840c86005e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e1d71-4969-7406-8eb1-08661c9a1700" xlink:to="loc_us-gaap_EarningsPerShareBasic_019e1d71-4969-7e01-b832-840c86005e5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019e1d71-4969-791b-a03e-0b17d15fd78f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019e1d71-4969-7406-8eb1-08661c9a1700" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019e1d71-4969-791b-a03e-0b17d15fd78f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_WeightedAverageNumberOfShareOutstandingAbstract_019e1d71-4969-7415-8387-56e8487b2899" xlink:href="ddd-20260630.xsd#ddd_WeightedAverageNumberOfShareOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-770a-af83-5e111b37a3c1" xlink:to="loc_ddd_WeightedAverageNumberOfShareOutstandingAbstract_019e1d71-4969-7415-8387-56e8487b2899" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e1d71-4969-7b17-a39f-e4bfddab248c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_WeightedAverageNumberOfShareOutstandingAbstract_019e1d71-4969-7415-8387-56e8487b2899" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e1d71-4969-7b17-a39f-e4bfddab248c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e1d71-4969-7c82-9524-dbe11eee07df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_WeightedAverageNumberOfShareOutstandingAbstract_019e1d71-4969-7415-8387-56e8487b2899" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e1d71-4969-7c82-9524-dbe11eee07df" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/CondensedConsolidatedStatementsofStockholdersEquityUnaudited" xlink:type="simple" xlink:href="ddd-20260630.xsd#CondensedConsolidatedStatementsofStockholdersEquityUnaudited"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/CondensedConsolidatedStatementsofStockholdersEquityUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019e1d71-4969-7d8b-892e-c600b544538b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019e1d71-4969-76d7-9a07-0e4908d96bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-7d8b-892e-c600b544538b" xlink:to="loc_us-gaap_StatementTable_019e1d71-4969-76d7-9a07-0e4908d96bc1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4969-71b0-ac1b-5ce478e5b6d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019e1d71-4969-76d7-9a07-0e4908d96bc1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4969-71b0-ac1b-5ce478e5b6d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e1d71-4969-71b0-ac1b-5ce478e5b6d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4969-71b0-ac1b-5ce478e5b6d4" xlink:to="loc_us-gaap_EquityComponentDomain_019e1d71-4969-71b0-ac1b-5ce478e5b6d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4969-71b0-ac1b-5ce478e5b6d4" xlink:to="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019e1d71-4969-76ff-81ed-f8701a0a3be4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:to="loc_us-gaap_CommonStockMember_019e1d71-4969-76ff-81ed-f8701a0a3be4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019e1d71-4969-7b69-8f99-a84add1764a4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019e1d71-4969-7b69-8f99-a84add1764a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019e1d71-4969-767c-a57f-ae0bb2cec3e6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:to="loc_us-gaap_RetainedEarningsMember_019e1d71-4969-767c-a57f-ae0bb2cec3e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4969-7a9e-89d6-065188e7040b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e1d71-4969-7d31-a879-d7cdc4063a47" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4969-7a9e-89d6-065188e7040b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019e1d71-4969-7d8b-892e-c600b544538b" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_019e1d71-4969-7023-bea7-01a3a748c81b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_SharesIssued_019e1d71-4969-7023-bea7-01a3a748c81b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e1d71-4969-7827-b158-6e6cf26d3313" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockholdersEquity_019e1d71-4969-7827-b158-6e6cf26d3313" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodShares_019f6a7b-b82a-70c3-8a03-9c7d9db2c117" xlink:href="ddd-20260630.xsd#ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodShares_019f6a7b-b82a-70c3-8a03-9c7d9db2c117" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodValue_019f6a7c-51d1-7711-8270-82dd50834fa8" xlink:href="ddd-20260630.xsd#ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_ddd_StockIssuedVestedAndExpiredUnderCompensationPlanDuringPeriodValue_019f6a7c-51d1-7711-8270-82dd50834fa8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019e1d71-4969-70c0-b497-2141308105d9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019e1d71-4969-70c0-b497-2141308105d9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e1d71-4969-76df-8ef7-8e499556064f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019e1d71-4969-76df-8ef7-8e499556064f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019ef77a-156f-7f46-87ef-3d8ce31599d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019ef77a-156f-7f46-87ef-3d8ce31599d5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_019ef77a-808d-7ced-abec-7427cefb05b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_019ef77a-808d-7ced-abec-7427cefb05b0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e1d71-4969-70be-b25c-38c59a730610" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e1d71-4969-70be-b25c-38c59a730610" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019e1d71-4969-7b95-9f24-d4a41c55e45a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_NetIncomeLoss_019e1d71-4969-7b95-9f24-d4a41c55e45a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_019e1d71-4969-7207-afd8-ffa61946ead9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_019e1d71-4969-7207-afd8-ffa61946ead9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019ef774-32f0-7f97-b188-2ce3b5180016" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019ef774-32f0-7f97-b188-2ce3b5180016" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019ef774-a881-75ee-be58-843df87729d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019ef774-a881-75ee-be58-843df87729d0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e1d71-4969-7500-a04c-374c0cdf758c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1d71-4969-7932-be07-e9aed24e9e71" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e1d71-4969-7500-a04c-374c0cdf758c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_019e1d71-4969-7879-bb9d-bd1b1f6d2326" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesIssued"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e1d71-4969-7fa4-9b7f-f1ed53129e0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/BASISOFPRESENTATIONDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#BASISOFPRESENTATIONDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/BASISOFPRESENTATIONDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:href="ddd-20260630.xsd#ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_019e1d71-4969-7045-a6f3-a9bd791a6485" xlink:href="ddd-20260630.xsd#ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_019e1d71-4969-7045-a6f3-a9bd791a6485" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019e1d71-4969-789d-83fc-2e14039d1895" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_019e1d71-4969-7045-a6f3-a9bd791a6485" xlink:to="loc_srt_OwnershipAxis_019e1d71-4969-789d-83fc-2e14039d1895" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e1d71-4969-789d-83fc-2e14039d1895_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019e1d71-4969-789d-83fc-2e14039d1895" xlink:to="loc_srt_OwnershipDomain_019e1d71-4969-789d-83fc-2e14039d1895_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019e1d71-4969-72e7-8c93-1b42a9c3303d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019e1d71-4969-789d-83fc-2e14039d1895" xlink:to="loc_srt_OwnershipDomain_019e1d71-4969-72e7-8c93-1b42a9c3303d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_KumovisGmbHMember_019e1d71-4969-78e3-947d-849b31e1e6eb" xlink:href="ddd-20260630.xsd#ddd_KumovisGmbHMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019e1d71-4969-72e7-8c93-1b42a9c3303d" xlink:to="loc_ddd_KumovisGmbHMember_019e1d71-4969-78e3-947d-849b31e1e6eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019e1d71-4969-7756-abe7-ecee241b957e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_NumberOfReportableSegments_019e1d71-4969-7756-abe7-ecee241b957e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019f8b73-2d5c-765c-984d-d36e36420b30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019f8b73-2d5c-765c-984d-d36e36420b30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019f4110-7277-7cf3-96a6-1a40b9319d02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019f4110-7277-7cf3-96a6-1a40b9319d02" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromOtherEquity_019f8b73-998e-7797-9e89-f00c7e7a99df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromOtherEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_ProceedsFromOtherEquity_019f8b73-998e-7797-9e89-f00c7e7a99df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_019e1d71-4969-7100-849f-aafe084914c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_019e1d71-4969-7100-849f-aafe084914c1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019e1d71-4969-7164-9fa2-4d8b4a7de118" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_019e1d71-4969-7164-9fa2-4d8b4a7de118" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_019e1d71-4969-790a-ace3-3e3c1e79c60b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_019e1d71-4969-790a-ace3-3e3c1e79c60b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019e1d71-4969-7d2f-be17-c2f55195424b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019e1d71-4969-7d2f-be17-c2f55195424b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e1d71-4969-7b9a-a5d5-3bd1429ebbf0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_019e1d71-4969-7b9a-a5d5-3bd1429ebbf0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_RedeemableNoncontrollingInterestPutOptionExerciseAmount_019e1d71-4969-79d3-a879-353cb86fc25d" xlink:href="ddd-20260630.xsd#ddd_RedeemableNoncontrollingInterestPutOptionExerciseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_ddd_RedeemableNoncontrollingInterestPutOptionExerciseAmount_019e1d71-4969-79d3-a879-353cb86fc25d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_RedeemableNoncontrollingInterestNumberOfInstallmentPayments_019e1d71-4969-7edf-b1f3-375a83a51921" xlink:href="ddd-20260630.xsd#ddd_RedeemableNoncontrollingInterestNumberOfInstallmentPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_ddd_RedeemableNoncontrollingInterestNumberOfInstallmentPayments_019e1d71-4969-7edf-b1f3-375a83a51921" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_PaymentsOfNonControllingInterest_019e1d71-4969-76ba-936e-5d946332c8d2" xlink:href="ddd-20260630.xsd#ddd_PaymentsOfNonControllingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_ddd_PaymentsOfNonControllingInterest_019e1d71-4969-76ba-936e-5d946332c8d2" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_RedeemableNoncontrollingInterestShortTermLiability_019e1d71-4969-7b2a-b76c-5d484425b273" xlink:href="ddd-20260630.xsd#ddd_RedeemableNoncontrollingInterestShortTermLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ddd_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_019e1d71-4969-73a1-b0c7-842ea3cd477a" xlink:to="loc_ddd_RedeemableNoncontrollingInterestShortTermLiability_019e1d71-4969-7b2a-b76c-5d484425b273" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/REVENUESNarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#REVENUESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/REVENUESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a32-b00c-1dc05422a4c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a32-b00c-1dc05422a4c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementMember_019e1d71-4969-79d4-b68f-752d4370cbe7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollaborativeArrangementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:to="loc_us-gaap_CollaborativeArrangementMember_019e1d71-4969-79d4-b68f-752d4370cbe7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e1d71-4969-72d6-ae5b-f4b5d0241a1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e1d71-4969-72d6-ae5b-f4b5d0241a1d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-77b3-96f8-518213dcec92_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-77b3-96f8-518213dcec92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_CustomerOneMember_019e1d71-4969-7a7b-a3d5-18523cb49fc8" xlink:href="ddd-20260630.xsd#ddd_CustomerOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:to="loc_ddd_CustomerOneMember_019e1d71-4969-7a7b-a3d5-18523cb49fc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_CustomerTwoMember_019e1d71-4969-7f9b-9677-f379074479d7" xlink:href="ddd-20260630.xsd#ddd_CustomerTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:to="loc_ddd_CustomerTwoMember_019e1d71-4969-7f9b-9677-f379074479d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7502-baf6-a1ec3521f999_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7502-baf6-a1ec3521f999_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_019e1d71-4969-7553-a63d-49d420041e14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_019e1d71-4969-7553-a63d-49d420041e14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-799e-987c-5ffe7d94a85c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-799e-987c-5ffe7d94a85c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019e1d71-4969-7d81-967a-2a45725ec40d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019e1d71-4969-7d81-967a-2a45725ec40d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_019e1d71-4969-7cc2-ae5d-d02b26eb8591" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_019e1d71-4969-7cc2-ae5d-d02b26eb8591" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance_019e1d71-4969-7fcd-9e9a-911f8891f38f" xlink:href="ddd-20260630.xsd#ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance_019e1d71-4969-7fcd-9e9a-911f8891f38f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-7a98-9ca1-fc6d944fc75a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-7a98-9ca1-fc6d944fc75a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-7628-a4e2-3ee6955d1783" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-7628-a4e2-3ee6955d1783" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e1d71-4969-702b-b9d0-8c676a31f200" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e1d71-4969-702b-b9d0-8c676a31f200" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e1d71-4969-792a-b59b-88b805a2384a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e1d71-4969-792a-b59b-88b805a2384a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e1d71-4969-7d35-88ec-cd535943a830" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e1d71-4969-7d35-88ec-cd535943a830" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e1d71-4969-7191-9c37-fc9d7fc5d7e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e1d71-4969-7191-9c37-fc9d7fc5d7e5" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/REVENUESNarrativeDetails_1" xlink:type="simple" xlink:href="ddd-20260630.xsd#REVENUESNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/REVENUESNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a32-b00c-1dc05422a4c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a32-b00c-1dc05422a4c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_019e1d71-4969-7a32-b00c-1dc05422a4c7" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementMember_019e1d71-4969-79d4-b68f-752d4370cbe7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollaborativeArrangementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_019e1d71-4969-7a79-a836-2343abcd2086" xlink:to="loc_us-gaap_CollaborativeArrangementMember_019e1d71-4969-79d4-b68f-752d4370cbe7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-77b3-96f8-518213dcec92_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-77b3-96f8-518213dcec92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019e1d71-4969-77b3-96f8-518213dcec92" xlink:to="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_CustomerOneMember_019e1d71-4969-7a7b-a3d5-18523cb49fc8" xlink:href="ddd-20260630.xsd#ddd_CustomerOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:to="loc_ddd_CustomerOneMember_019e1d71-4969-7a7b-a3d5-18523cb49fc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_CustomerTwoMember_019e1d71-4969-7f9b-9677-f379074479d7" xlink:href="ddd-20260630.xsd#ddd_CustomerTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019e1d71-4969-782c-9710-1abc8332e26b" xlink:to="loc_ddd_CustomerTwoMember_019e1d71-4969-7f9b-9677-f379074479d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7502-baf6-a1ec3521f999_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7502-baf6-a1ec3521f999_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019e1d71-4969-7502-baf6-a1ec3521f999" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_019e1d71-4969-7553-a63d-49d420041e14" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019e1d71-4969-7098-8c52-4dde4f2cdbe8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_019e1d71-4969-7553-a63d-49d420041e14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_019e1d71-4969-7c8b-803b-9726da9bfdb2" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-799e-987c-5ffe7d94a85c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-799e-987c-5ffe7d94a85c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019e1d71-4969-799e-987c-5ffe7d94a85c" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019e1d71-4969-7d81-967a-2a45725ec40d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019e1d71-4969-7559-8b9a-f0ea0667aa55" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019e1d71-4969-7d81-967a-2a45725ec40d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_019e1d71-4969-7cc2-ae5d-d02b26eb8591" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_019e1d71-4969-7cc2-ae5d-d02b26eb8591" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance_019e1d71-4969-7fcd-9e9a-911f8891f38f" xlink:href="ddd-20260630.xsd#ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_ddd_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance_019e1d71-4969-7fcd-9e9a-911f8891f38f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-7a98-9ca1-fc6d944fc75a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-7a98-9ca1-fc6d944fc75a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-7628-a4e2-3ee6955d1783" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4969-7628-a4e2-3ee6955d1783" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_019e1d71-4969-702b-b9d0-8c676a31f200" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_019e1d71-4969-702b-b9d0-8c676a31f200" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e1d71-4969-792a-b59b-88b805a2384a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e1d71-4969-792a-b59b-88b805a2384a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e1d71-4969-7d35-88ec-cd535943a830" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e1d71-4969-7d35-88ec-cd535943a830" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019e1d71-4969-7191-9c37-fc9d7fc5d7e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_019e1d71-4969-77e2-9d0d-3690ab9600c1" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019e1d71-4969-7191-9c37-fc9d7fc5d7e5" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/REVENUESScheduleofRevenuebyGeographicRegionDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#REVENUESScheduleofRevenuebyGeographicRegionDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/REVENUESScheduleofRevenuebyGeographicRegionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019e1d71-4969-7e21-a92b-147a873d8350" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019e1d71-4969-7f41-bff5-26d09759b7c8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e1d71-4969-7e21-a92b-147a873d8350" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019e1d71-4969-7f41-bff5-26d09759b7c8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019e1d71-4969-7d0c-b4e7-4c43c225f384" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019e1d71-4969-7f41-bff5-26d09759b7c8" xlink:to="loc_srt_StatementGeographicalAxis_019e1d71-4969-7d0c-b4e7-4c43c225f384" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e1d71-4969-7d0c-b4e7-4c43c225f384_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019e1d71-4969-7d0c-b4e7-4c43c225f384" xlink:to="loc_srt_SegmentGeographicalDomain_019e1d71-4969-7d0c-b4e7-4c43c225f384_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019e1d71-4969-77ee-a0ce-e7ffe9b7cdbf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019e1d71-4969-7d0c-b4e7-4c43c225f384" xlink:to="loc_srt_SegmentGeographicalDomain_019e1d71-4969-77ee-a0ce-e7ffe9b7cdbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_019e1d71-4969-7344-ac6b-c6ca2290c2d8" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e1d71-4969-77ee-a0ce-e7ffe9b7cdbf" xlink:to="loc_srt_AmericasMember_019e1d71-4969-7344-ac6b-c6ca2290c2d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_019e1d71-4969-7f10-8d89-bc543a46bfc0" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_AmericasMember_019e1d71-4969-7344-ac6b-c6ca2290c2d8" xlink:to="loc_country_US_019e1d71-4969-7f10-8d89-bc543a46bfc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_019e1d71-4969-783c-ac0b-8dc7fa228aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e1d71-4969-77ee-a0ce-e7ffe9b7cdbf" xlink:to="loc_us-gaap_EMEAMember_019e1d71-4969-783c-ac0b-8dc7fa228aa0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_DE_019e1d71-4969-74fa-834c-4e4c078a4b1d" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_DE"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EMEAMember_019e1d71-4969-783c-ac0b-8dc7fa228aa0" xlink:to="loc_country_DE_019e1d71-4969-74fa-834c-4e4c078a4b1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_019e1d71-4969-7bca-af09-32638796e578" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019e1d71-4969-77ee-a0ce-e7ffe9b7cdbf" xlink:to="loc_srt_AsiaPacificMember_019e1d71-4969-7bca-af09-32638796e578" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-71cf-a39a-d91c6dce2c43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019e1d71-4969-7e21-a92b-147a873d8350" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4969-71cf-a39a-d91c6dce2c43" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/DIVESTITUREDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#DIVESTITUREDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/DIVESTITUREDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019e1d71-4969-7a2a-851a-98130fc38567" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019e1d71-4969-70e0-97e1-2326b7e2c40d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019e1d71-4969-7a2a-851a-98130fc38567" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019e1d71-4969-70e0-97e1-2326b7e2c40d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019e1d71-4969-7612-bb65-2a1e9424fbb6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019e1d71-4969-70e0-97e1-2326b7e2c40d" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019e1d71-4969-7612-bb65-2a1e9424fbb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019e1d71-4969-7612-bb65-2a1e9424fbb6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019e1d71-4969-7612-bb65-2a1e9424fbb6" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019e1d71-4969-7612-bb65-2a1e9424fbb6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019e1d71-4969-7ddb-b166-7c48f3c12359" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_019e1d71-4969-7612-bb65-2a1e9424fbb6" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019e1d71-4969-7ddb-b166-7c48f3c12359" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_GeomagicSoftwareMember_019e1d71-4969-70ad-9dfb-f39c2b00dce2" xlink:href="ddd-20260630.xsd#ddd_GeomagicSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_019e1d71-4969-7ddb-b166-7c48f3c12359" xlink:to="loc_ddd_GeomagicSoftwareMember_019e1d71-4969-70ad-9dfb-f39c2b00dce2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019e1d71-4969-7c89-a82c-2937d41f49b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019e1d71-4969-70e0-97e1-2326b7e2c40d" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019e1d71-4969-7c89-a82c-2937d41f49b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019e1d71-4969-7c89-a82c-2937d41f49b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019e1d71-4969-7c89-a82c-2937d41f49b4" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019e1d71-4969-7c89-a82c-2937d41f49b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019e1d71-4969-7c1a-a90a-c5dc264b4e3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019e1d71-4969-7c89-a82c-2937d41f49b4" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019e1d71-4969-7c1a-a90a-c5dc264b4e3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019e1d71-4969-785c-90c8-56bab54d6081" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019e1d71-4969-7c1a-a90a-c5dc264b4e3a" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_019e1d71-4969-785c-90c8-56bab54d6081" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019e1d71-4969-7102-b493-840028c0c60f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019e1d71-4969-7a2a-851a-98130fc38567" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_019e1d71-4969-7102-b493-840028c0c60f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_019e1d71-4969-79bd-b6a1-7d2b83cfc9b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019e1d71-4969-7a2a-851a-98130fc38567" xlink:to="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_019e1d71-4969-79bd-b6a1-7d2b83cfc9b2" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/INVESTMENTSANDNOTERECEIVABLENarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#INVESTMENTSANDNOTERECEIVABLENarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/INVESTMENTSANDNOTERECEIVABLENarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019e1d71-4969-73ef-b3a7-361bc236c069" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019e1d71-4969-73ef-b3a7-361bc236c069" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e1d71-4969-7281-af2d-177c5a706c1d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019e1d71-4969-73ef-b3a7-361bc236c069" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e1d71-4969-7281-af2d-177c5a706c1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7281-af2d-177c5a706c1d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e1d71-4969-7281-af2d-177c5a706c1d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7281-af2d-177c5a706c1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7584-80b9-8c633c1aabfd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e1d71-4969-7281-af2d-177c5a706c1d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7584-80b9-8c633c1aabfd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_NationalAdditiveManufacturingInnovationMember_019e1d71-4969-7c13-ae1c-672579e411e6" xlink:href="ddd-20260630.xsd#ddd_NationalAdditiveManufacturingInnovationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7584-80b9-8c633c1aabfd" xlink:to="loc_ddd_NationalAdditiveManufacturingInnovationMember_019e1d71-4969-7c13-ae1c-672579e411e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_EntachIncMember_019e1d71-4969-7f6d-90e3-579db40f9165" xlink:href="ddd-20260630.xsd#ddd_EntachIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7584-80b9-8c633c1aabfd" xlink:to="loc_ddd_EntachIncMember_019e1d71-4969-7f6d-90e3-579db40f9165" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_HullLegacyMediaCorporationMember_019e1d71-4969-77e2-b72a-1ecb3cd9e172" xlink:href="ddd-20260630.xsd#ddd_HullLegacyMediaCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019e1d71-4969-7584-80b9-8c633c1aabfd" xlink:to="loc_ddd_HullLegacyMediaCorporationMember_019e1d71-4969-77e2-b72a-1ecb3cd9e172" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e1d71-4969-7d91-bb2b-430457fe6f06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019e1d71-4969-73ef-b3a7-361bc236c069" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e1d71-4969-7d91-bb2b-430457fe6f06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e1d71-4969-7d91-bb2b-430457fe6f06_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e1d71-4969-7d91-bb2b-430457fe6f06" xlink:to="loc_us-gaap_RelatedPartyDomain_019e1d71-4969-7d91-bb2b-430457fe6f06_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_019e1d71-4969-7f72-807b-0fdde6ad6336" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e1d71-4969-7d91-bb2b-430457fe6f06" xlink:to="loc_us-gaap_RelatedPartyDomain_019e1d71-4969-7f72-807b-0fdde6ad6336" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_019e1d71-4969-715d-9e1b-e8dd9b7d79ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_019e1d71-4969-7f72-807b-0fdde6ad6336" xlink:to="loc_us-gaap_RelatedPartyMember_019e1d71-4969-715d-9e1b-e8dd9b7d79ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e1d71-4969-7c3d-a9d3-bfb648f22746" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e1d71-4969-7c3d-a9d3-bfb648f22746" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e1d71-4969-7cf5-b998-51c98dd5a6b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019e1d71-4969-7cf5-b998-51c98dd5a6b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ShortTermNonInterestBearingLoan_019e1d71-4969-7179-99fc-7e569a669211" xlink:href="ddd-20260630.xsd#ddd_ShortTermNonInterestBearingLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_ddd_ShortTermNonInterestBearingLoan_019e1d71-4969-7179-99fc-7e569a669211" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019e1d71-4969-7634-88f2-65239e8a7422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_NotesAndLoansReceivableNetCurrent_019e1d71-4969-7634-88f2-65239e8a7422" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fa3a4-69ab-7e65-bc79-69d6f97c0f97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019fa3a4-69ab-7e65-bc79-69d6f97c0f97" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_019e1d71-4969-770d-aa53-66b226b42320" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_AccountsPayableCurrent_019e1d71-4969-770d-aa53-66b226b42320" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e1d71-4969-7e08-872e-0859199f5e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e1d71-4969-7e08-872e-0859199f5e9b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForPurchaseOfOtherAssets1_019e1d71-4969-7ebe-b579-638b50391105" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForPurchaseOfOtherAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_PaymentsForPurchaseOfOtherAssets1_019e1d71-4969-7ebe-b579-638b50391105" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_VariableInterestEntityNumberOfEntities_019e1d71-4969-7545-94ab-2f2621b613c4" xlink:href="ddd-20260630.xsd#ddd_VariableInterestEntityNumberOfEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_ddd_VariableInterestEntityNumberOfEntities_019e1d71-4969-7545-94ab-2f2621b613c4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019e1d71-4969-77cb-b93f-579b3f99366c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1d71-4969-7d8e-b603-14c6df3b36b2" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019e1d71-4969-77cb-b93f-579b3f99366c" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/BORROWINGSScheduleofConvertibleNotesPayableDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#BORROWINGSScheduleofConvertibleNotesPayableDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/BORROWINGSScheduleofConvertibleNotesPayableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-751f-bc6b-945f50e4d815" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-751f-bc6b-945f50e4d815" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-78b5-b58f-52b266c7b699" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-751f-bc6b-945f50e4d815" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-78b5-b58f-52b266c7b699" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-78b5-b58f-52b266c7b699_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-78b5-b58f-52b266c7b699" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-78b5-b58f-52b266c7b699_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7453-97e1-458e4efc9470" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-78b5-b58f-52b266c7b699" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7453-97e1-458e4efc9470" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4969-732a-ad79-5dcb24b42a3c" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7453-97e1-458e4efc9470" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4969-732a-ad79-5dcb24b42a3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4969-708b-bd61-8bfba6ba2b1c" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7453-97e1-458e4efc9470" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4969-708b-bd61-8bfba6ba2b1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-7cad-8306-74a606037944" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-751f-bc6b-945f50e4d815" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-7cad-8306-74a606037944" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7cad-8306-74a606037944_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-7cad-8306-74a606037944" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7cad-8306-74a606037944_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7c7a-b08b-02576eb8955f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-7cad-8306-74a606037944" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7c7a-b08b-02576eb8955f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e1d71-4969-72d9-9173-af6fd9029dca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7c7a-b08b-02576eb8955f" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e1d71-4969-72d9-9173-af6fd9029dca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4969-7ae7-af75-27593930234c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4969-7ae7-af75-27593930234c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019e1d71-4969-7bf6-a408-c545de40556d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019e1d71-4969-7bf6-a408-c545de40556d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_019e1d71-4969-7e60-a6dc-27b7669e0475" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_019e1d71-4969-7e60-a6dc-27b7669e0475" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e1d71-4969-774c-8bf1-19400284e7e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7d18-a6ee-e209dc80eba2" xlink:to="loc_us-gaap_LongTermDebt_019e1d71-4969-774c-8bf1-19400284e7e1" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/BORROWINGSNarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#BORROWINGSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/BORROWINGSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7b79-84e3-3023d5d8d422" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-7a79-a393-f11d23642fe6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7b79-84e3-3023d5d8d422" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-7a79-a393-f11d23642fe6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-7bf3-b98d-659d43ace37c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-7a79-a393-f11d23642fe6" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-7bf3-b98d-659d43ace37c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7bf3-b98d-659d43ace37c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-7bf3-b98d-659d43ace37c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7bf3-b98d-659d43ace37c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7454-b9ea-74565f28e152" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4969-7bf3-b98d-659d43ace37c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7454-b9ea-74565f28e152" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4969-788b-b614-631c3714f231" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7454-b9ea-74565f28e152" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4969-788b-b614-631c3714f231" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4969-723a-ac4b-97a04fc4a18c" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4969-7454-b9ea-74565f28e152" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4969-723a-ac4b-97a04fc4a18c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-786b-a72a-458c3947c0aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_019e1d71-4969-7a79-a393-f11d23642fe6" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-786b-a72a-458c3947c0aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-786b-a72a-458c3947c0aa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-786b-a72a-458c3947c0aa" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-786b-a72a-458c3947c0aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7f32-8aa7-91389cd193f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4969-786b-a72a-458c3947c0aa" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7f32-8aa7-91389cd193f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e1d71-4969-7b36-8667-ae037d7fc0ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4969-7f32-8aa7-91389cd193f9" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e1d71-4969-7b36-8667-ae037d7fc0ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4969-7d9a-88d1-a55ee90f499b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7b79-84e3-3023d5d8d422" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4969-7d9a-88d1-a55ee90f499b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e1d71-4969-758b-94eb-8e014ba089c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7b79-84e3-3023d5d8d422" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019e1d71-4969-758b-94eb-8e014ba089c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_019e1d71-4969-7501-90dc-ce0a8f05eb29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_019e1d71-4969-7b79-84e3-3023d5d8d422" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_019e1d71-4969-7501-90dc-ce0a8f05eb29" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/STOCKBASEDCOMPENSATIONNarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#STOCKBASEDCOMPENSATIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/STOCKBASEDCOMPENSATIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e1d71-4969-7a5c-b0a7-a8ca0792636f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e1d71-4969-7a5c-b0a7-a8ca0792636f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e1d71-4969-75f6-a597-70576aa993ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e1d71-4969-7a5c-b0a7-a8ca0792636f" xlink:to="loc_us-gaap_AwardTypeAxis_019e1d71-4969-75f6-a597-70576aa993ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-75f6-a597-70576aa993ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e1d71-4969-75f6-a597-70576aa993ab" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-75f6-a597-70576aa993ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-7c1b-bf65-78dc04825962" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e1d71-4969-75f6-a597-70576aa993ab" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-7c1b-bf65-78dc04825962" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_019ef822-490f-7512-8853-b05280ff6801" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-7c1b-bf65-78dc04825962" xlink:to="loc_us-gaap_PerformanceSharesMember_019ef822-490f-7512-8853-b05280ff6801" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019f8b13-52bf-7204-ac70-41c67cff8ead" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4969-7c1b-bf65-78dc04825962" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019f8b13-52bf-7204-ac70-41c67cff8ead" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019ef822-490f-7d66-a449-40af1ec1e5af" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019ef822-490f-7d66-a449-40af1ec1e5af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019ef822-490f-73af-a660-14a1991f1f2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019ef822-490f-73af-a660-14a1991f1f2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e1d71-4969-7240-bc10-33d64ac78ceb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e1d71-4969-7240-bc10-33d64ac78ceb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ShareBasedPaymentArrangementReversalOfExpense_019f4150-07fe-716e-ab76-84eb0ff1e7ad" xlink:href="ddd-20260630.xsd#ddd_ShareBasedPaymentArrangementReversalOfExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_ddd_ShareBasedPaymentArrangementReversalOfExpense_019f4150-07fe-716e-ab76-84eb0ff1e7ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019e1d71-4969-7d89-a374-a794f2e9e743" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_019e1d71-4969-7d89-a374-a794f2e9e743" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019f8b68-5612-7df2-95a3-aee81bf927c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1d71-4969-7d4a-9b25-4599f8cbc616" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019f8b68-5612-7df2-95a3-aee81bf927c1" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/NETLOSSINCOMEPERSHAREScheduleofPotentiallyDilutiveSharesDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#NETLOSSINCOMEPERSHAREScheduleofPotentiallyDilutiveSharesDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/NETLOSSINCOMEPERSHAREScheduleofPotentiallyDilutiveSharesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicLineItems_019e1d71-4a20-776e-9e5b-ad664a7aac47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasicLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019e1d71-4a20-7b84-b09a-17008d01d4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019e1d71-4a20-776e-9e5b-ad664a7aac47" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019e1d71-4a20-7b84-b09a-17008d01d4d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019e1d71-4a20-751f-89b3-e77bb547cdfa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_019e1d71-4a20-7b84-b09a-17008d01d4d2" xlink:to="loc_us-gaap_AwardTypeAxis_019e1d71-4a20-751f-89b3-e77bb547cdfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-751f-89b3-e77bb547cdfa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019e1d71-4a20-751f-89b3-e77bb547cdfa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-751f-89b3-e77bb547cdfa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-786e-973a-1778d9fc8d2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019e1d71-4a20-751f-89b3-e77bb547cdfa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-786e-973a-1778d9fc8d2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_RestrictedStockRestrictedStockUnitsAndPSUsMember_019e1d71-4a20-7f22-9709-8ba1d13b5b83" xlink:href="ddd-20260630.xsd#ddd_RestrictedStockRestrictedStockUnitsAndPSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-786e-973a-1778d9fc8d2e" xlink:to="loc_ddd_RestrictedStockRestrictedStockUnitsAndPSUsMember_019e1d71-4a20-7f22-9709-8ba1d13b5b83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockOptionMember_019e1d71-4a20-7ba0-abba-fa32f0d7c4f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1d71-4a20-786e-973a-1778d9fc8d2e" xlink:to="loc_us-gaap_StockOptionMember_019e1d71-4a20-7ba0-abba-fa32f0d7c4f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e1d71-4a20-76ff-a602-66b3bfd6122f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_019e1d71-4a20-776e-9e5b-ad664a7aac47" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e1d71-4a20-76ff-a602-66b3bfd6122f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSINCOMEDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSINCOMEDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSINCOMEDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e1d71-4a20-7f05-95ec-60e442620666" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e1d71-4a20-71a7-87fb-01cf3ca69851" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e1d71-4a20-7f05-95ec-60e442620666" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e1d71-4a20-71a7-87fb-01cf3ca69851" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4a20-7a1b-9c71-c5e1798ec473" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e1d71-4a20-71a7-87fb-01cf3ca69851" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4a20-7a1b-9c71-c5e1798ec473" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e1d71-4a20-7a1b-9c71-c5e1798ec473_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4a20-7a1b-9c71-c5e1798ec473" xlink:to="loc_us-gaap_EquityComponentDomain_019e1d71-4a20-7a1b-9c71-c5e1798ec473_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019e1d71-4a20-73d1-b8b4-24d5c720033c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019e1d71-4a20-7a1b-9c71-c5e1798ec473" xlink:to="loc_us-gaap_EquityComponentDomain_019e1d71-4a20-73d1-b8b4-24d5c720033c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4a20-779e-9811-605150fd7fbe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019e1d71-4a20-73d1-b8b4-24d5c720033c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4a20-779e-9811-605150fd7fbe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019e1d71-4a20-77fa-a27c-6a79b00d3794" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4a20-779e-9811-605150fd7fbe" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_019e1d71-4a20-77fa-a27c-6a79b00d3794" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019e1d71-4a20-7674-9627-c98d3d131697" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1d71-4a20-779e-9811-605150fd7fbe" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019e1d71-4a20-7674-9627-c98d3d131697" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e1d71-4a20-7b2e-bdf6-2e4b7edb6cbb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e1d71-4a20-7f05-95ec-60e442620666" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e1d71-4a20-7b2e-bdf6-2e4b7edb6cbb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e1d71-4a20-762d-ac61-c4ea035fe49b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e1d71-4a20-7b2e-bdf6-2e4b7edb6cbb" xlink:to="loc_us-gaap_StockholdersEquity_019e1d71-4a20-762d-ac61-c4ea035fe49b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e1d71-4a20-7bba-9047-4e9b081cb35f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_019e1d71-4a20-7b2e-bdf6-2e4b7edb6cbb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019e1d71-4a20-7bba-9047-4e9b081cb35f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019e1d71-4a20-7486-ac6f-f80798d0074a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/SEGMENTINFORMATIONScheduleofOperatingResultsbySegmentDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#SEGMENTINFORMATIONScheduleofOperatingResultsbySegmentDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/SEGMENTINFORMATIONScheduleofOperatingResultsbySegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7327-95c8-3407a39d8bd8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7327-95c8-3407a39d8bd8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-72c3-83aa-038ab05300f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7327-95c8-3407a39d8bd8" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-72c3-83aa-038ab05300f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-72c3-83aa-038ab05300f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-72c3-83aa-038ab05300f6" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-72c3-83aa-038ab05300f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-7554-89e2-701241dc64f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-72c3-83aa-038ab05300f6" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-7554-89e2-701241dc64f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-76e5-afa4-a12a6724b983" xlink:href="ddd-20260630.xsd#ddd_HealthcareSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-7554-89e2-701241dc64f3" xlink:to="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-76e5-afa4-a12a6724b983" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-75f2-918e-e69f98def3bd" xlink:href="ddd-20260630.xsd#ddd_IndustrialSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-7554-89e2-701241dc64f3" xlink:to="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-75f2-918e-e69f98def3bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_019e1d71-4a20-7e40-9c09-78edc02293f3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7327-95c8-3407a39d8bd8" xlink:to="loc_srt_ConsolidationItemsAxis_019e1d71-4a20-7e40-9c09-78edc02293f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-7e40-9c09-78edc02293f3_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_019e1d71-4a20-7e40-9c09-78edc02293f3" xlink:to="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-7e40-9c09-78edc02293f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-72cf-8e07-5726c2834ccf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_019e1d71-4a20-7e40-9c09-78edc02293f3" xlink:to="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-72cf-8e07-5726c2834ccf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_019e1d71-4a20-7b10-b66a-2a3c54f968e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-72cf-8e07-5726c2834ccf" xlink:to="loc_us-gaap_OperatingSegmentsMember_019e1d71-4a20-7b10-b66a-2a3c54f968e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaterialReconcilingItemsMember_019e1d71-4a20-7cb7-a67e-24912f4fffc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MaterialReconcilingItemsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_019e1d71-4a20-72cf-8e07-5726c2834ccf" xlink:to="loc_us-gaap_MaterialReconcilingItemsMember_019e1d71-4a20-7cb7-a67e-24912f4fffc6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019e1d71-4a20-7f2b-8b78-9a4105689247" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_RevenuesAbstract_019e1d71-4a20-7f2b-8b78-9a4105689247" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4a20-7065-b6db-ce078ae24d86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019e1d71-4a20-7f2b-8b78-9a4105689247" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1d71-4a20-7065-b6db-ce078ae24d86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4a20-74d9-891b-fdf857950ca1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSoldAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4a20-74d9-891b-fdf857950ca1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4a20-70fd-9c5a-f3f135fdc883" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_019e1d71-4a20-74d9-891b-fdf857950ca1" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_019e1d71-4a20-70fd-9c5a-f3f135fdc883" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfitAbstract_019e1d71-4a20-7620-9188-9b0cdd8a381a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfitAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_GrossProfitAbstract_019e1d71-4a20-7620-9188-9b0cdd8a381a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_019e1d71-4a20-7060-8389-78e85ceada5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GrossProfitAbstract_019e1d71-4a20-7620-9188-9b0cdd8a381a" xlink:to="loc_us-gaap_GrossProfit_019e1d71-4a20-7060-8389-78e85ceada5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e1d71-4a20-77bf-8c05-f5eab10108d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_019e1d71-4a20-77bf-8c05-f5eab10108d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019e1d71-4a20-7a58-8843-3f29bc142a71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019e1d71-4a20-7a58-8843-3f29bc142a71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e1d71-4a20-74db-a065-c66d69cd49fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_019e1d71-4a20-74db-a065-c66d69cd49fd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_019e1d71-4a20-72b1-a3bb-826fb054cea4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_InvestmentIncomeInterest_019e1d71-4a20-72b1-a3bb-826fb054cea4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInvestmentExpense_019e1d71-4a20-7ea7-a678-584eac71cc20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInvestmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_InvestmentIncomeInvestmentExpense_019e1d71-4a20-7ea7-a678-584eac71cc20" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_019ef84a-dc61-7b9f-8c68-bfb4f05ef17b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_019ef84a-dc61-7b9f-8c68-bfb4f05ef17b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019e1d71-4a20-7915-a8d5-868ad3f5ef99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019e1d71-4a20-7915-a8d5-868ad3f5ef99" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsIncomeTaxesNoncontrollingInterestAdjusted_019e1d71-4a20-7dbe-a7b2-2db221084275" xlink:href="ddd-20260630.xsd#ddd_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsIncomeTaxesNoncontrollingInterestAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7b84-8719-ffcadbad3e6d" xlink:to="loc_ddd_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsIncomeTaxesNoncontrollingInterestAdjusted_019e1d71-4a20-7dbe-a7b2-2db221084275" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/SEGMENTINFORMATIONScheduleofDepreciationandAmortizationDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#SEGMENTINFORMATIONScheduleofDepreciationandAmortizationDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/SEGMENTINFORMATIONScheduleofDepreciationandAmortizationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7e02-b311-28ca33320316" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7e20-bf7e-105325f77a68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7e02-b311-28ca33320316" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7e20-bf7e-105325f77a68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-7c4c-8fd5-dc196604d1ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1d71-4a20-7e20-bf7e-105325f77a68" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-7c4c-8fd5-dc196604d1ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-7c4c-8fd5-dc196604d1ba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-7c4c-8fd5-dc196604d1ba" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-7c4c-8fd5-dc196604d1ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-77d0-9b63-5abf270795b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-7c4c-8fd5-dc196604d1ba" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-77d0-9b63-5abf270795b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-780b-8404-9649cd9ed0e8" xlink:href="ddd-20260630.xsd#ddd_HealthcareSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-77d0-9b63-5abf270795b1" xlink:to="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-780b-8404-9649cd9ed0e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-7062-9252-61a09ded06d8" xlink:href="ddd-20260630.xsd#ddd_IndustrialSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-77d0-9b63-5abf270795b1" xlink:to="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-7062-9252-61a09ded06d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_019e1d71-4a20-7629-bb7b-053080ecd26b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019e1d71-4a20-7e02-b311-28ca33320316" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_019e1d71-4a20-7629-bb7b-053080ecd26b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/COMMITMENTSANDCONTINGENCIESNarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#COMMITMENTSANDCONTINGENCIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/COMMITMENTSANDCONTINGENCIESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019e1d71-4a20-78db-afeb-86218b974dee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_us-gaap_LossContingenciesTable_019e1d71-4a20-78db-afeb-86218b974dee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_019f6aba-ef31-7d7e-84c3-e855cf1a3216" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019e1d71-4a20-78db-afeb-86218b974dee" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_019f6aba-ef31-7d7e-84c3-e855cf1a3216" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_019f6aba-ef31-7d7e-84c3-e855cf1a3216_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_019f6aba-ef31-7d7e-84c3-e855cf1a3216" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_019f6aba-ef31-7d7e-84c3-e855cf1a3216_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_019f6aba-ef31-7bdb-8329-f48de4f470d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_019f6aba-ef31-7d7e-84c3-e855cf1a3216" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_019f6aba-ef31-7bdb-8329-f48de4f470d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019f6aba-ef31-7f38-84f6-1afea7399234" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialStandbyLetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_019f6aba-ef31-7bdb-8329-f48de4f470d3" xlink:to="loc_us-gaap_FinancialStandbyLetterOfCreditMember_019f6aba-ef31-7f38-84f6-1afea7399234" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseObligation_019f6aba-cb46-7b20-8df8-190366de51a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PurchaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_us-gaap_PurchaseObligation_019f6aba-cb46-7b20-8df8-190366de51a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseObligationDueInNextTwelveMonths_019f6aba-cb46-7a1d-a80f-33a46ac9bfde" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PurchaseObligationDueInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_us-gaap_PurchaseObligationDueInNextTwelveMonths_019f6aba-cb46-7a1d-a80f-33a46ac9bfde" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_019f6aba-ef31-7ae2-800b-c36ddf95a399" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_019f6aba-ef31-7ae2-800b-c36ddf95a399" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_GuarantorObligationsExtensionTerm_019f6aba-ef31-7c92-8778-d58d315d7cd5" xlink:href="ddd-20260630.xsd#ddd_GuarantorObligationsExtensionTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_ddd_GuarantorObligationsExtensionTerm_019f6aba-ef31-7c92-8778-d58d315d7cd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_019f6aba-ef31-74c8-bcee-3af9e092996d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019f6aba-cb46-77ed-823f-0517c930cbab" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_019f6aba-ef31-74c8-bcee-3af9e092996d" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e1d71-4a20-7bb8-836d-70d5315abafa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e1d71-4a20-7a8b-bb26-dd5c90628fa3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e1d71-4a20-7bb8-836d-70d5315abafa" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e1d71-4a20-7a8b-bb26-dd5c90628fa3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019e1d71-4a20-7150-9b60-e2885a380fe9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e1d71-4a20-7a8b-bb26-dd5c90628fa3" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019e1d71-4a20-7150-9b60-e2885a380fe9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e1d71-4a20-7150-9b60-e2885a380fe9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e1d71-4a20-7150-9b60-e2885a380fe9" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e1d71-4a20-7150-9b60-e2885a380fe9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e1d71-4a20-74da-85ea-8e5934566ef9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019e1d71-4a20-7150-9b60-e2885a380fe9" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e1d71-4a20-74da-85ea-8e5934566ef9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_019e1d71-4a20-714a-95ce-50dbbb45ba44" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019e1d71-4a20-74da-85ea-8e5934566ef9" xlink:to="loc_us-gaap_MoneyMarketFundsMember_019e1d71-4a20-714a-95ce-50dbbb45ba44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e1d71-4a20-745a-bdf3-e4385a98a7e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e1d71-4a20-7a8b-bb26-dd5c90628fa3" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e1d71-4a20-745a-bdf3-e4385a98a7e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-745a-bdf3-e4385a98a7e4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e1d71-4a20-745a-bdf3-e4385a98a7e4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-745a-bdf3-e4385a98a7e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-7a17-b253-6879076aca69" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e1d71-4a20-745a-bdf3-e4385a98a7e4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-7a17-b253-6879076aca69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019e1d71-4a20-701d-a142-adf9c1935ab2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-7a17-b253-6879076aca69" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019e1d71-4a20-701d-a142-adf9c1935ab2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019e1d71-4a20-79a9-831c-e63a42f65f59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-7a17-b253-6879076aca69" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019e1d71-4a20-79a9-831c-e63a42f65f59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019e1d71-4a20-71f5-a838-328f7b9d2ebe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1d71-4a20-7a17-b253-6879076aca69" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019e1d71-4a20-71f5-a838-328f7b9d2ebe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e1d71-4a20-73d2-9d0f-4e4216b5c192" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e1d71-4a20-7bb8-836d-70d5315abafa" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019e1d71-4a20-73d2-9d0f-4e4216b5c192" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/FAIRVALUEMEASUREMENTSScheduleofFairValueofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#FAIRVALUEMEASUREMENTSScheduleofFairValueofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/FAIRVALUEMEASUREMENTSScheduleofFairValueofFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e1d71-4a20-7f8f-86ab-a7345126cd8a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e1d71-4a20-7598-921e-f72045a68066" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e1d71-4a20-7f8f-86ab-a7345126cd8a" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e1d71-4a20-7598-921e-f72045a68066" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019e1d71-4a20-742c-b742-41f79fee086b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e1d71-4a20-7598-921e-f72045a68066" xlink:to="loc_us-gaap_DebtInstrumentAxis_019e1d71-4a20-742c-b742-41f79fee086b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-742c-b742-41f79fee086b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4a20-742c-b742-41f79fee086b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-742c-b742-41f79fee086b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-7b22-b46d-bda59429ef51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019e1d71-4a20-742c-b742-41f79fee086b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-7b22-b46d-bda59429ef51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4a20-7b71-b5ea-b8b0f782ff56" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-7b22-b46d-bda59429ef51" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2026Member_019e1d71-4a20-7b71-b5ea-b8b0f782ff56" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4a20-7f44-93ec-ae24f58fb369" xlink:href="ddd-20260630.xsd#ddd_ConvertibleSeniorNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019e1d71-4a20-7b22-b46d-bda59429ef51" xlink:to="loc_ddd_ConvertibleSeniorNotesDue2030Member_019e1d71-4a20-7f44-93ec-ae24f58fb369" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4a20-71ad-bb88-a60359c6af2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_019e1d71-4a20-7598-921e-f72045a68066" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4a20-71ad-bb88-a60359c6af2a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4a20-71ad-bb88-a60359c6af2a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4a20-71ad-bb88-a60359c6af2a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4a20-71ad-bb88-a60359c6af2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4a20-756f-aa8e-ae774a5aefbc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019e1d71-4a20-71ad-bb88-a60359c6af2a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4a20-756f-aa8e-ae774a5aefbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_019e1d71-4a20-7ae8-9b90-312fe505ad47" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019e1d71-4a20-756f-aa8e-ae774a5aefbc" xlink:to="loc_us-gaap_ConvertibleDebtMember_019e1d71-4a20-7ae8-9b90-312fe505ad47" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4a20-7c48-a2d7-9fd91da46414" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e1d71-4a20-7f8f-86ab-a7345126cd8a" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1d71-4a20-7c48-a2d7-9fd91da46414" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019e1d71-4a20-7067-b6ae-677aca05306d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e1d71-4a20-7f8f-86ab-a7345126cd8a" xlink:to="loc_us-gaap_LongTermDebt_019e1d71-4a20-7067-b6ae-677aca05306d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_019e1d71-4a20-78f5-8175-d072082ded97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019e1d71-4a20-7f8f-86ab-a7345126cd8a" xlink:to="loc_us-gaap_DebtInstrumentFairValue_019e1d71-4a20-78f5-8175-d072082ded97" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7d83-81f9-c2f59b4ee934" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7d83-81f9-c2f59b4ee934" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-7099-be52-4b0261f8a4ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7d83-81f9-c2f59b4ee934" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-7099-be52-4b0261f8a4ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-74ef-9d20-2230a2db6b78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-74ef-9d20-2230a2db6b78" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails_1" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7d83-81f9-c2f59b4ee934" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7d83-81f9-c2f59b4ee934" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-74ef-9d20-2230a2db6b78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-71f2-baa5-27619dfb9858" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-74ef-9d20-2230a2db6b78" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7bf6-929f-c6de7e1e0d7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7bf6-929f-c6de7e1e0d7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-7189-afc6-094ea49e162f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7bf6-929f-c6de7e1e0d7d" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-7189-afc6-094ea49e162f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7393-8b23-68573826ed3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7393-8b23-68573826ed3e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails_1" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails_1"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostsIncurredDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7bf6-929f-c6de7e1e0d7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7bf6-929f-c6de7e1e0d7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7393-8b23-68573826ed3e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7cef-9be5-53a19f403cba" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7393-8b23-68573826ed3e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-794b-96bd-14721936d903_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-794b-96bd-14721936d903_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-72dd-983d-fbc6757f5d32" xlink:href="ddd-20260630.xsd#ddd_HealthcareSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:to="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-72dd-983d-fbc6757f5d32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-72e1-bbfa-0af6acfe5c7e" xlink:href="ddd-20260630.xsd#ddd_IndustrialSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:to="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-72e1-bbfa-0af6acfe5c7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-75b9-85cb-df54cfcd1f07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_019e1d71-4a20-75b9-85cb-df54cfcd1f07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-75bf-bdc6-f14dfad7c7b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-75bf-bdc6-f14dfad7c7b1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails_1" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails_1"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofCostofSalesbyReportableSegmentDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-73ce-a9c0-defeca857b4e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-794b-96bd-14721936d903_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-794b-96bd-14721936d903_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019e1d71-4a20-794b-96bd-14721936d903" xlink:to="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-72dd-983d-fbc6757f5d32" xlink:href="ddd-20260630.xsd#ddd_HealthcareSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:to="loc_ddd_HealthcareSolutionsMember_019e1d71-4a20-72dd-983d-fbc6757f5d32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-72e1-bbfa-0af6acfe5c7e" xlink:href="ddd-20260630.xsd#ddd_IndustrialSolutionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019e1d71-4a20-774f-919b-c82c6835d8c4" xlink:to="loc_ddd_IndustrialSolutionsMember_019e1d71-4a20-72e1-bbfa-0af6acfe5c7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-75bf-bdc6-f14dfad7c7b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7e4b-baee-d2d0a829ef7e" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-75bf-bdc6-f14dfad7c7b1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofRestructuringChargesDetails" xlink:type="simple" xlink:href="ddd-20260630.xsd#RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofRestructuringChargesDetails"/>
  <link:definitionLink xlink:role="http://www.3dsystems.com/role/RESTRUCTURINGANDEXITACTIVITIESCOSTSScheduleofRestructuringChargesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7ac3-a2ab-24f18fdb0366" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7356-8b59-d97c2d5850ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7ac3-a2ab-24f18fdb0366" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7356-8b59-d97c2d5850ab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_019e1d71-4a20-793e-aade-d2f5e25ca6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_019e1d71-4a20-7356-8b59-d97c2d5850ab" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_019e1d71-4a20-793e-aade-d2f5e25ca6c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019e1d71-4a20-793e-aade-d2f5e25ca6c2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019e1d71-4a20-793e-aade-d2f5e25ca6c2" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019e1d71-4a20-793e-aade-d2f5e25ca6c2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_019e1d71-4a20-7e25-8009-56c60f88aad2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_019e1d71-4a20-793e-aade-d2f5e25ca6c2" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_019e1d71-4a20-7e25-8009-56c60f88aad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_019e1d71-4a20-7bcd-a6e0-ef0ad7741e67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_019e1d71-4a20-7e25-8009-56c60f88aad2" xlink:to="loc_us-gaap_EmployeeSeveranceMember_019e1d71-4a20-7bcd-a6e0-ef0ad7741e67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_019e1d71-4a20-7895-92ed-9d5d5bf18539" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_019e1d71-4a20-7ac3-a2ab-24f18fdb0366" xlink:to="loc_us-gaap_RestructuringReserveRollForward_019e1d71-4a20-7895-92ed-9d5d5bf18539" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_019e1d71-4a20-74be-b507-c4b71b55e1f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_019e1d71-4a20-7895-92ed-9d5d5bf18539" xlink:to="loc_us-gaap_RestructuringReserve_019e1d71-4a20-74be-b507-c4b71b55e1f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7c55-8d07-2ba52c10aded" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_019e1d71-4a20-7895-92ed-9d5d5bf18539" xlink:to="loc_us-gaap_RestructuringCharges_019e1d71-4a20-7c55-8d07-2ba52c10aded" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_019e1d71-4a20-7969-b2dc-6f9e8d698583" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_019e1d71-4a20-7895-92ed-9d5d5bf18539" xlink:to="loc_us-gaap_PaymentsForRestructuring_019e1d71-4a20-7969-b2dc-6f9e8d698583" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_019e1d71-4a20-7d4b-a1c0-e0d7fe778ea0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestructuringReserve"/>
  </link:definitionLink>
</link:linkbase>
