# Define up\_dir value

**URL:** <https://community.geodynamics.org/t/define-up-dir-value/1678>\
**Category:** PyLith\
**Created:** [February 4, 2021, 4:59pm UTC](https://community.geodynamics.org/t/define-up-dir-value/1678 "2021-02-04T16:59:25Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![alvinakkuncoro](https://avatars.discourse-cdn.com/v4/letter/a/ba8739/32.png) [@alvinakkuncoro](https://community.geodynamics.org/u/alvinakkuncoro)\
**Post date:** [February 5, 2021, 2:44pm UTC](https://community.geodynamics.org/t/define-up-dir-value/1678/6 "2021-02-05T14:44:02Z")

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I would like to do interseismic and earthquake cycle simulation using my own geometry (figure attached below).  
The white block is the oceanic crust, the pink block is the accretionary wedge, the chocolate block is the continental crust.  
( I am also preparing another geometry with a bigger size because the continental part is too narrow and previously I had mesh quality issues

 ![geometry](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/1X/47cbc897c6625b81b524116bc766e8cd1d2e07f0.jpeg) ).

I have tried using (0,0,1) and I received this error :  
_RuntimeError: Error computing orientation of cell face. Cannot resolve tangential components into unambigious directions._  
_Up direction (0, 0, 1) cannot be parallel to the face normal (0, 0, 1)._  
_If the face is horizontal, adjust the up\_dir parameter._

I also tried to undefined the updir value but I got the same error.

Thank you in advance.

Regards,  
Alvina KK

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