# Why does a solid geometry convert to a shell part when imported in PrePoMax?

**URL:** <https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738>\
**Category:** General Questions\
**Created:** [May 13, 2024, 4:17am UTC](https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738 "2024-05-13T04:17:18Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Majid](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@Majid](https://prepomax.discourse.group/u/Majid)\
**Post date:** [May 13, 2024, 4:17am UTC](https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738/1 "2024-05-13T04:17:18Z")

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Hello,

I have a problem with PrePoMax. I modeled an assembly model (solid geometry) in Catia. The parts are converted to a shell once the model is imported into PrePoMax. Also, in the “Part type” of each part has been written “Solid as shell”. Does anyone know why it is so? How can I fix it?  
Please see te figure attached. Thank you.

 ![IMG_1900](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/9/9ab6b998e6333b37de8e02cdeb193b3776e3e5c1.jpeg)  
 ![IMG_1901](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/f/f93967d4f0c86562a71cd42fec74196f9f382a01.jpeg)  
 ![IMG_1902](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/e/e6650eb188f0342320191d975b51be0930ec05b4.jpeg)

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**Author:** ![arnie](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@arnie](https://prepomax.discourse.group/u/arnie)\
**Post date:** [May 13, 2024, 5:41am UTC](https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738/2 "2024-05-13T05:41:58Z")

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What format did you export as ?  
Perhaps try STEP and see if you get same result.

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**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\
**Post date:** [May 13, 2024, 6:27am UTC](https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738/3 "2024-05-13T06:27:19Z")

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If the type of the part in PrePoMax is “solid as shell” this shows the solid is recognized and is displayed as outer shell only. This is the normal type for all solids. So the section cut will reveal an “empty” inside. After meshing, everything will be solid.

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**Author:** ![Majid](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@Majid](https://prepomax.discourse.group/u/Majid)\
**Post date:** [May 13, 2024, 7:19am UTC](https://prepomax.discourse.group/t/why-does-a-solid-geometry-convert-to-a-shell-part-when-imported-in-prepomax/1738/4 "2024-05-13T07:19:12Z")

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Dear @Matej thank you for your kind reply. Yes you are right.