# Geometry | Get intersection point to roof surface

**URL:** https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884
**Category:** Revit
**Created:** [March 10, 2020, 7:56am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884 "2020-03-10T07:56:53Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![zalgirietis.minde](https://avatars.discourse-cdn.com/v4/letter/z/dbc845/32.png) [@zalgirietis.minde](https://forum.dynamobim.com/u/zalgirietis.minde)
#### Post date: [March 10, 2020, 7:56am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884/1 "2020-03-10T07:56:53Z")

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Hi Dynamo Users,

I’m trying to retrieve the distance between my point and roof surface in my project.  
With this node based version I’m able to to retrieve the closest point to the surface (P1) which is, I believe, perpendicular line to that surface.  
I’m actually looking for P2.  
A quick Question here: Should I create a line using my point as a start point along the Z axis and look for intersection point? Maybe you know some other nodes that I can use and get a fast result?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/c/e/ce67f974868537d747e3de36d522196b41b4751d.png)

 ![22](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/4/9/49e0c8f00d19800473284a650bcf65dd8ede5dcc.png)  
Just need someone’s advice of how to get this done better. I’m pretty sure that I’m very close. Thanks.

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### Author: ![AlexanderBerg](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/alexanderberg/32/82944_2.png) [@AlexanderBerg](https://forum.dynamobim.com/u/AlexanderBerg)
#### Post date: [March 10, 2020, 8:44am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884/2 "2020-03-10T08:44:23Z")

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Is this what you looking for?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/e/7/e78ac64d18a9bc39d181aa30a4fa44c1a9c655ee.png)

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### Author: ![zalgirietis.minde](https://avatars.discourse-cdn.com/v4/letter/z/dbc845/32.png) [@zalgirietis.minde](https://forum.dynamobim.com/u/zalgirietis.minde)
#### Post date: [March 10, 2020, 9:02am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884/3 "2020-03-10T09:02:23Z")

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If not highlighted line is parallel to Z axis, then yes.  
As I can see, Point.Project was the node I was looking for.

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### Author: ![AlexanderBerg](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/alexanderberg/32/82944_2.png) [@AlexanderBerg](https://forum.dynamobim.com/u/AlexanderBerg)
#### Post date: [March 10, 2020, 9:12am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884/4 "2020-03-10T09:12:11Z")

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I’ve did indeed highlighted the perpendicular, but the node `Point.Project` does just that; projecting point onto geometry in the given vector and as you can see, provided vector is `Z.Axis` so the point is vertically projected.

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### Author: ![zalgirietis.minde](https://avatars.discourse-cdn.com/v4/letter/z/dbc845/32.png) [@zalgirietis.minde](https://forum.dynamobim.com/u/zalgirietis.minde)
#### Post date: [March 10, 2020, 9:48am UTC](https://forum.dynamobim.com/t/geometry-get-intersection-point-to-roof-surface/47884/5 "2020-03-10T09:48:15Z")

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Thanks a lot, @AlexanderBerg.  
Saved me some time for sure!