I am trying to find the intersection line between two objects with geometry mesh boolean to make a procedural weld but I can't seem to find out how to do it.

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1 Answer 1


Blender 3.0 - 3.3

If you have two meshes and want to select their intersection, use the following nodes:

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Here I first capture the edges of one bar with Capture Attribute before I merge the two shapes with the node Mesh Boolean.

After that I simply remove the previously selected edges with Delete Geometry and only the intersection line remains.

But of course you can apply the same game with selecting and deleting directly to your mesh created with Mesh Boolean:

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Blender 3.4+

Starting from this version, the node Mesh Boolean directly outputs the intersecting edges to a socket, making the solution a lot easier:

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  • 1
    $\begingroup$ Thanks a lot, this is exactly what i needed. I never used Capture attribute with a boolean before. I am trying to wrap my head around why this works but i will figure it out eventually. Awesome work, much appreciated. $\endgroup$
    – Roel Deden
    Jun 10, 2022 at 7:45
  • $\begingroup$ Nice trick there, helped me too. Thank you. $\endgroup$
    – ofekp
    Aug 28, 2022 at 23:51
  • $\begingroup$ I think it works because Union has to add new edges and vertices at the weld. We delete all the vertices belonging to the old meshes and that leaves us with the newly created vertices. Amazing solution! $\endgroup$ Sep 10, 2022 at 13:51

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