# How to use DAGMC geometry

**URL:** <https://openmc.discourse.group/t/how-to-use-dagmc-geometry/3966>\
**Category:** User Support\
**Created:** [February 27, 2024, 2:42am UTC](https://openmc.discourse.group/t/how-to-use-dagmc-geometry/3966 "2024-02-27T02:42:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mooncake](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@mooncake](https://openmc.discourse.group/u/mooncake)\
**Post date:** [February 27, 2024, 2:42am UTC](https://openmc.discourse.group/t/how-to-use-dagmc-geometry/3966/1 "2024-02-27T02:42:42Z")

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Dear developers, I am a beginner at openmc, may I ask how to represent CAD-based geometry in a surface mesh format by DAGMC geometry?

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<div class="post-metadata">

**Author:** ![Shimwell](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/shimwell/32/3876_2.png) [@Shimwell](https://openmc.discourse.group/u/Shimwell)\
**Post date:** [February 27, 2024, 11:38am UTC](https://openmc.discourse.group/t/how-to-use-dagmc-geometry/3966/2 "2024-02-27T11:38:09Z")

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Welcome to the community

This is a big topic but there are some packages out there to help convert CAD to DAGMC h5m files.

[Here is a list of DAGMC tools including geometry conversion packages](https://github.com/svalinn/DAGMC/discussions/812)

After you have your DAGMC h5m file then it can be included in an openmc model with the DAGMCUniverse here is a link to the docs for that class  
[https://docs.openmc.org/en/latest/pythonapi/generated/openmc.DAGMCUniverse.html](https://docs.openmc.org/en/latest/pythonapi/generated/openmc.DAGMCUniverse.html)