Generating　an　interior　support　structure　is　a　key　issue　in　3D　model　geometric　optimization　for　3D　printing.　Most　existing　interior　support　structures　have　been　designed　by　simulating　lightweight　structures　naturally　exist.　One　limitation　of　the　existing　method　is　that　only　one　single　structure　is　used　for　the　model.　However,　different　parts　of　a　3D　model　have　different　shapes　and　mechanical　properties　and　different　structures　demonstrate　distinctive　advantages　for　supporting　the　model.　Based　on　such　observation,　we　propose　to　use　hybrid　structures　for　designing　an　optimal　support　structure.　In　this　paper,　we　present　a　novel　scheme　of　generating　hybrid　interior　support　structures　for　3D　printing.　The　proposed　approach　first　partitions　an　input　model　into　parts　with　different　physical　behaviors.　Different　interior　structures　are　generated　for　each　part,　and　the　interior　structures　are　finally　joined　together.　Experimental　results　demonstrate　that　the　proposed　hybrid　structure　obtains　higher　strength-to-weight　ratio　than　recent　competing　approaches　that　use　single　types　of　interior　structures.　(C)　2018　Elsevier　B.V.　All　rights　reserved.