# Geometry.Intersectall got the empty list

**URL:** <https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185>\
**Category:** Revit\
**Created:** [August 7, 2019, 8:08am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185 "2019-08-07T08:08:01Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![dz480](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@dz480](https://forum.dynamobim.com/u/dz480)\
**Post date:** [August 7, 2019, 8:08am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/1 "2019-08-07T08:08:01Z")

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Good morning all,

I try to use Geometry.Intersectall to filter the mesh, cause I only want to get the mesh on the analysis surface (red boundary). But I don’t know where I did wrong steps and I got the empty list.

Anyone could help me fix this?

Many thanks

 ![%E5%BE%AE%E4%BF%A1%E6%88%AA%E5%9B%BE_20190807085840](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/d/fd19f801cf047b5c0933965973ad0b8d5d2f1a01.png)

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**Author:** ![Akli.baliche](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Akli.baliche](https://forum.dynamobim.com/u/Akli.baliche)\
**Post date:** [August 7, 2019, 8:16am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/2 "2019-08-07T08:16:56Z")

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Do your geometry cross each other?  
if there is more than one surface, switch Lacing in Cross Product

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<div class="post-metadata">

**Author:** ![dz480](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@dz480](https://forum.dynamobim.com/u/dz480)\
**Post date:** [August 7, 2019, 8:28am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/3 "2019-08-07T08:28:45Z")

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Yes, I think so. The surface and the mesh, both of them are in the same level.  
I tried to switch lacing in Cross Product. It looks working, but I’m wondering how I can remove the rest mesh I don’t want?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/a/6/a66ad58a99af00ef02c11a0cd81c8596ec971a1d.png)

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<div class="post-metadata">

**Author:** ![Akli.baliche](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Akli.baliche](https://forum.dynamobim.com/u/Akli.baliche)\
**Post date:** [August 7, 2019, 8:31am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/4 "2019-08-07T08:31:45Z")

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mask the precious knots to see the final result.  
to do it: right button on the node- Preview

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<div class="post-metadata">

**Author:** ![dz480](https://avatars.discourse-cdn.com/v4/letter/d/7ea924/32.png) [@dz480](https://forum.dynamobim.com/u/dz480)\
**Post date:** [August 7, 2019, 8:35am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/5 "2019-08-07T08:35:24Z")

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It works!!!  
Thank you very much!  
I feel like I have no idea about Dynamo. HAHA…

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<div class="post-metadata">

**Author:** ![Akli.baliche](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Akli.baliche](https://forum.dynamobim.com/u/Akli.baliche)\
**Post date:** [August 7, 2019, 8:40am UTC](https://forum.dynamobim.com/t/geometry-intersectall-got-the-empty-list/39185/6 "2019-08-07T08:40:07Z")

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it will come