# Filtering Surface By Axis Plane

**URL:** <https://forum.dynamobim.com/t/filtering-surface-by-axis-plane/102820>\
**Category:** Revit\
**Tags:** revit, geometry, dynamo\
**Created:** [July 17, 2024, 12:06am UTC](https://forum.dynamobim.com/t/filtering-surface-by-axis-plane/102820 "2024-07-17T00:06:47Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ikhsan.pc](https://avatars.discourse-cdn.com/v4/letter/i/e68b1a/32.png) [@ikhsan.pc](https://forum.dynamobim.com/u/ikhsan.pc)\
**Post date:** [July 17, 2024, 12:06am UTC](https://forum.dynamobim.com/t/filtering-surface-by-axis-plane/102820/1 "2024-07-17T00:06:47Z")

</div>

How do I filter surfaces according to the axis plane only, those facing the same axis plane, the following surfaces I have filtered vertically

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/7/8/78c88d3574aed5ccc02e22ea0120fdb2dab12a2e.jpeg)  
 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/a/0a3e78ad2e81468a7e2b34ee95f10dc746af437e.png)

---

<div class="post-metadata">

**Author:** ![Mike.Buttery](https://avatars.discourse-cdn.com/v4/letter/m/b19c9b/32.png) [@Mike.Buttery](https://forum.dynamobim.com/u/Mike.Buttery)\
**Post date:** [July 17, 2024, 1:28am UTC](https://forum.dynamobim.com/t/filtering-surface-by-axis-plane/102820/2 "2024-07-17T01:28:14Z")

</div>

Use _Surface.NormalAtParameter_ to get the normal vectors and then use _Vector.IsParallel_ to check alignment

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/4/d/4dc31ab47c2e91341e92ab04d3b2aeda3f0bdb0c.png)

---

<div class="post-metadata">

**Author:** ![ikhsan.pc](https://avatars.discourse-cdn.com/v4/letter/i/e68b1a/32.png) [@ikhsan.pc](https://forum.dynamobim.com/u/ikhsan.pc)\
**Post date:** [July 17, 2024, 8:35am UTC](https://forum.dynamobim.com/t/filtering-surface-by-axis-plane/102820/3 "2024-07-17T08:35:44Z")

</div>

Thank you, I’ll try