# Project creates different results

**URL:** <https://fenicsproject.discourse.group/t/project-creates-different-results/5003>\
**Category:** Uncategorized\
**Created:** [January 28, 2021, 9:26pm UTC](https://fenicsproject.discourse.group/t/project-creates-different-results/5003 "2021-01-28T21:26:38Z")\
**Posts on this page:** 1\
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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 29, 2021, 3:49pm UTC](https://fenicsproject.discourse.group/t/project-creates-different-results/5003/18 "2021-01-29T15:49:35Z")

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I am just giving you the tools to do what you would like to do. The code in the «parts of domain» approach is a working example of a custom projection.  
In your case, you are trying to project a derivative of a 3D field into 2D. There are several things you could consider:  
-first project `func3dz` into an appropriate 3D space (DG degree-1)

- then i think you should be able to interpolate into 2D.  
You should Also inspect the behavior of `func3dz` after projection using `xdmf.write_checkpoint` and visualize it with paraview.

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