# how to write 3d lattice in openmc

**URL:** <https://openmc.discourse.group/t/how-to-write-3d-lattice-in-openmc/516>\
**Category:** User Support\
**Created:** [November 28, 2019, 8:37am UTC](https://openmc.discourse.group/t/how-to-write-3d-lattice-in-openmc/516 "2019-11-28T08:37:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Kirti\_Singla](https://avatars.discourse-cdn.com/v4/letter/k/c4cdca/32.png) [@Kirti\_Singla](https://openmc.discourse.group/u/Kirti_Singla)\
**Post date:** [November 28, 2019, 8:37am UTC](https://openmc.discourse.group/t/how-to-write-3d-lattice-in-openmc/516/1 "2019-11-28T08:37:27Z")

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Hi  
I am facing problem in writting 3 dimensional array.How to write in xml??

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**Author:** ![Javier\_Gonzalez](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/javier_gonzalez/32/1095_2.png) [@Javier\_Gonzalez](https://openmc.discourse.group/u/Javier_Gonzalez)\
**Post date:** [November 28, 2019, 2:33pm UTC](https://openmc.discourse.group/t/how-to-write-3d-lattice-in-openmc/516/2 "2019-11-28T14:33:44Z")

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Hi Kirti,

I recommend using python API to create the model ([https://docs.openmc.org/en/v0.11.0/usersguide/install.html#](https://docs.openmc.org/en/v0.11.0/usersguide/install.html#)). In the examples you can find how to do that array ([https://docs.openmc.org/en/v0.11.0/examples/pandas-dataframes.html](https://docs.openmc.org/en/v0.11.0/examples/pandas-dataframes.html)).

Hope this helps,  
Javier