# How I can to get a surface angle to a vertical line?

**URL:** <https://forum.dynamobim.com/t/how-i-can-to-get-a-surface-angle-to-a-vertical-line/59979>\
**Category:** Revit\
**Tags:** revit, geometry, dynamo\
**Created:** [February 1, 2021, 7:06pm UTC](https://forum.dynamobim.com/t/how-i-can-to-get-a-surface-angle-to-a-vertical-line/59979 "2021-02-01T19:06:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![SPN](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/spn/32/54414_2.png) [@SPN](https://forum.dynamobim.com/u/SPN)\
**Post date:** [February 1, 2021, 7:06pm UTC](https://forum.dynamobim.com/t/how-i-can-to-get-a-surface-angle-to-a-vertical-line/59979/1 "2021-02-01T19:06:06Z")

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Hey all,

I am writing a code to calculate total surfaces areas of structural elements. However, in this code I want to filter-out the surfaces which are in certain range of angles, like the beam in the figure below.  
I would like to be able to test every face/surface of an selected element and go through a test (TRUE/FALSE) and calculate just the surfaces which meet the criteria.  
 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/c/fc6f548d41c90ce50007e3e8286260abbcc88d1e.png)

Can you help me please?

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**Author:** ![Vikram\_Subbaiah](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/vikram_subbaiah/32/50797_2.png) [@Vikram\_Subbaiah](https://forum.dynamobim.com/u/Vikram_Subbaiah)\
**Post date:** [February 1, 2021, 7:18pm UTC](https://forum.dynamobim.com/t/how-i-can-to-get-a-surface-angle-to-a-vertical-line/59979/2 "2021-02-01T19:18:37Z")

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> [@SPN](#):
>
> I want to filter-out the surfaces which are in certain range of angles

Calculate the angle between the Surface normal (normalize the vector obtained) with the Z-Axis

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<div class="post-metadata">

**Author:** ![SPN](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/spn/32/54414_2.png) [@SPN](https://forum.dynamobim.com/u/SPN)\
**Post date:** [February 1, 2021, 7:19pm UTC](https://forum.dynamobim.com/t/how-i-can-to-get-a-surface-angle-to-a-vertical-line/59979/3 "2021-02-01T19:19:50Z")

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I just found it. But thanks for the reply!

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/8/08b94085347b898983f1c88548bc2d26390d5963.png)

Please feel free to post other methods here.

Cheers!