# Probem in the openmc.model.rectangular\_prism

**URL:** <https://openmc.discourse.group/t/probem-in-the-openmc-model-rectangular-prism/3540>\
**Category:** User Support\
**Created:** [October 23, 2023, 8:19am UTC](https://openmc.discourse.group/t/probem-in-the-openmc-model-rectangular-prism/3540 "2023-10-23T08:19:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![j.gomezrodriguez](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/j.gomezrodriguez/32/4233_2.png) [@j.gomezrodriguez](https://openmc.discourse.group/u/j.gomezrodriguez)\
**Post date:** [October 23, 2023, 8:19am UTC](https://openmc.discourse.group/t/probem-in-the-openmc-model-rectangular-prism/3540/1 "2023-10-23T08:19:42Z")

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Dear all,  
I am trying to create an experimental channel inside of a reactor and to do so, I used the openmc.model.rectangular\_prism(width=3.6, height=3.6, axis =‘x’, origin(0,0)).  
However, as I input as axis, the x-axis, it gives me an error:  
KeyError: ‘Zplane’

Just as a trial, I put as axis, the z-axis and it does work, does somebody know what could be the problem. I need to put in in the x and not in the z.

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**Author:** ![Sabyasachi](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sabyasachi](https://openmc.discourse.group/u/Sabyasachi)\
**Post date:** [October 30, 2023, 6:50pm UTC](https://openmc.discourse.group/t/probem-in-the-openmc-model-rectangular-prism/3540/2 "2023-10-30T18:50:37Z")

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you can use ReactangularParallelpiped instead of rectangular prism. The advantage is you can bound the boundary three dimensionally. Hope that will help you.  
[Rectangular Parallel Piped](https://docs.openmc.org/en/latest/pythonapi/generated/openmc.model.RectangularParallelepiped.html#:~:text=class%20openmc.model.RectangularParallelepiped%28xmin%2C%20xmax%2C%20ymin%2C%20ymax%2C%20zmin%2C%20zmax%2C%20%2A%2Akwargs%29,operators%20applied%20to%20it%20will%20produce%20a%20half-space.) You can see the mentioned documentation for further help.

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**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\
**Post date:** [October 30, 2023, 7:41pm UTC](https://openmc.discourse.group/t/probem-in-the-openmc-model-rectangular-prism/3540/3 "2023-10-30T19:41:35Z")

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@j.gomezrodriguez The error you are seeing is due to a bug in version 0.13.3 that has already been fixed in development and will be part of our next release.