# Tutorial on 3D geometries

**URL:** <https://fenicsproject.discourse.group/t/tutorial-on-3d-geometries/7140>\
**Category:** dolfinx\
**Created:** [November 22, 2021, 11:00am UTC](https://fenicsproject.discourse.group/t/tutorial-on-3d-geometries/7140 "2021-11-22T11:00:11Z")\
**Posts on this page:** 1\
**Showing post:** 17

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**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [January 9, 2023, 7:00pm UTC](https://fenicsproject.discourse.group/t/tutorial-on-3d-geometries/7140/17 "2023-01-09T19:00:45Z")

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You do not want to cut out the circle, you want it to be meshed as part of the boundary. Probably you need to use the fragment command. See for instance [Mesh, Submesh , Torus, Boundary - #5 by dokken](https://fenicsproject.discourse.group/t/mesh-submesh-torus-boundary/6378/5)  
or  
[https://bthierry.pages.math.cnrs.fr/tutorial/gmsh/occ/basics/#boolean-operations-cad-like-a-boss-\_](https://bthierry.pages.math.cnrs.fr/tutorial/gmsh/occ/basics/#boolean-operations-cad-like-a-boss-_)  
or the Gmsh documentation.

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