# Geometry with openmc

**URL:** <https://openmc.discourse.group/t/geometry-with-openmc/6054>\
**Category:** Development\
**Created:** [October 13, 2025, 6:26pm UTC](https://openmc.discourse.group/t/geometry-with-openmc/6054 "2025-10-13T18:26:04Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![fakhar](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/fakhar/32/4224_2.png) [@fakhar](https://openmc.discourse.group/u/fakhar)\
**Post date:** [October 13, 2025, 6:26pm UTC](https://openmc.discourse.group/t/geometry-with-openmc/6054/1 "2025-10-13T18:26:04Z")

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I’m trying to recreate the geometry shown in my attached image using OpenMC and Python.

It consists of several _concentric layers_ (like squares with rounded corners), each one representing different materials — fuel, cladding, and water regions. I want to build this as a 3D or 2D

 ![71985aa3e61c8968554d03cdd8daa7b0bd6f904f](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/b/be2b79d4d74dbb3a5fa244f4b2163b02a48603d4.png)

model in OpenMC.

So far, I’ve tried using `openmc.model.rectangular_prism()` and Boolean operations between surfaces, but I’m not sure how to get the _rounded-square (filleted corner)_ shape or how to organize multiple layers cleanly.

Can anyone please guide me or share an example of how to draw this kind of geometry (possibly using cylinders or arcs for the corners)?  
Any help or code snippet would be greatly appreciated!

Thanks in advance!

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**Author:** ![wahidluthfi](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/wahidluthfi/32/3375_2.png) [@wahidluthfi](https://openmc.discourse.group/u/wahidluthfi)\
**Post date:** [October 13, 2025, 6:37pm UTC](https://openmc.discourse.group/t/geometry-with-openmc/6054/2 "2025-10-13T18:37:09Z")

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Hi Fakhar, I think [this](https://openmc.discourse.group/t/geometry-problem/4668) discussion will be interesting for you

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**Author:** ![fakhar](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/fakhar/32/4224_2.png) [@fakhar](https://openmc.discourse.group/u/fakhar)\
**Post date:** [October 13, 2025, 6:43pm UTC](https://openmc.discourse.group/t/geometry-with-openmc/6054/3 "2025-10-13T18:43:37Z")

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thank you so much , can i get your email , i want your help

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<div class="post-metadata">

**Author:** ![fakhar](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/fakhar/32/4224_2.png) [@fakhar](https://openmc.discourse.group/u/fakhar)\
**Post date:** [October 14, 2025, 10:30pm UTC](https://openmc.discourse.group/t/geometry-with-openmc/6054/4 "2025-10-14T22:30:44Z")

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hi , can you help me with this issue at layer 1

[test.ipynb](https://openmc.discourse.group/uploads/short-url/s1YFHmSQPzQ6EycbEVmXkCrcqWS.ipynb) (172.9 KB)