# Problems with importing 3D model

**URL:** <https://prepomax.discourse.group/t/problems-with-importing-3d-model/2233>\
**Category:** General Questions\
**Created:** [December 2, 2024, 9:30pm UTC](https://prepomax.discourse.group/t/problems-with-importing-3d-model/2233 "2024-12-02T21:30:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@Peter](https://prepomax.discourse.group/u/Peter)\
**Post date:** [December 2, 2024, 9:30pm UTC](https://prepomax.discourse.group/t/problems-with-importing-3d-model/2233/1 "2024-12-02T21:30:56Z")

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Hello,  
I am trying to use the PREPOMAX program to calculate a 3D thermal bridge. However, I have a problem with importing the 3D geometry. When I use the IGES format, the solid modeled object breaks up into shells. When I use the STP format, the program imports only one of the objects.  
I also tried different formats via FreeCAD.  
Can you please advise me where I might be making a mistake?

thanks

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<div class="post-metadata">

**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [December 2, 2024, 9:47pm UTC](https://prepomax.discourse.group/t/problems-with-importing-3d-model/2233/2 "2024-12-02T21:47:51Z")

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Exporting from FreeCAD can be tricky. Do you select all the objects in the tree before exporting to STEP (this format is the preferred one) ?