# Solid.ByUnion doesn work

**URL:** <https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674>\
**Category:** Geometry\
**Tags:** dynamo\
**Created:** [April 3, 2018, 8:15pm UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674 "2018-04-03T20:15:18Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![tpancingkom](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@tpancingkom](https://forum.dynamobim.com/u/tpancingkom)\
**Post date:** [April 3, 2018, 8:15pm UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674/1 "2018-04-03T20:15:18Z")

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Hi! Need asistance ! I’m try make one solid from stair with node Solid.ByUnion - but it doesnt work.  
Whats wrong?

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/e/6/e695bf4590b4bbb5bb0a68d8dad4b4a772464bd5.png)

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**Author:** ![Steven](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/steven/32/112504_2.png) [@Steven](https://forum.dynamobim.com/u/Steven)\
**Post date:** [April 3, 2018, 9:27pm UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674/2 "2018-04-03T21:27:50Z")

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The stairs do not intersect in the picture provided. To my understanding it will only work if everything is intersecting at some point so it can form one solid.

![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/9/9/99d00893a232b4614a78bb2db063ba50cec7b700.jpg)

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<div class="post-metadata">

**Author:** ![tpancingkom](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@tpancingkom](https://forum.dynamobim.com/u/tpancingkom)\
**Post date:** [April 4, 2018, 4:08am UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674/3 "2018-04-04T04:08:50Z")

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No, then i try union geometry only on one stair run - i have same trouble.

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**Author:** ![Dimitar\_Venkov](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/dimitar_venkov/32/2068_2.png) [@Dimitar\_Venkov](https://forum.dynamobim.com/u/Dimitar_Venkov)\
**Post date:** [April 4, 2018, 5:31am UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674/4 "2018-04-04T05:31:30Z")

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Both Revit and Dynamo support disjoined solids:

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/d/d/ddbc77faa78ac929c8d5e10675ef20f36029faca.png)

My guess is that the node is detecting some solid topology (edges, vertices) that are close together and is trying to merge them unsuccessfully.

In such cases there isn’t really much you can do other than extract the faces and use a Polysurface instead or tweak the input geometry…

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**Author:** ![tpancingkom](https://avatars.discourse-cdn.com/v4/letter/t/df705f/32.png) [@tpancingkom](https://forum.dynamobim.com/u/tpancingkom)\
**Post date:** [April 4, 2018, 8:02am UTC](https://forum.dynamobim.com/t/solid-byunion-doesn-work/20674/5 "2018-04-04T08:02:11Z")

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It isnt right way. Because stair run have to much dificult geometry.

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/e/0e0ad55c316d4d830b7f8cf8f7351730da6bae2e.png)