# Grasshopper solid union failed

Hi, I need help.
I want to create a model using Voronoi 3d and made it like the picture.
But, I failed solid union. (Boolean Union set is empty)
Using meshes is not a solution for my particular case.
Is there any good solution?

voronoi3d_solid_union.gh (13.0 KB)

I am afraid you have hit one of the walls of Rhino/GH.
Let’s do it in Fusion 360. Exported from Rhino as STEP.

flip last
re-voronoi3d_solid_union.gh (11.0 KB)

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@vincent1’s GH works perfectly in this case, but once the points number passes 18(this case), the union won’t work again.
I sincerely hope anyone can solve this, or at least explain why this does not work.

You have some piped curve segments that are very short. If you cull the shortest 10 in your list of curves, (of which the shortest 10 are no longer than 1.38 mm), the Solid Union will work. You can use Sort List and Cull index to remove the shortest curves from your list.

You can also use Sort List + Smaller Than + Cull Pattern to remove curve segments that are smaller than a given length. Removing the caps from the Pipe component will help with the Solid Union.

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By the way if you are using Rhino 7, Multipipe may be a better solution.

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re-voronoi3d_solid_union edited 1.gh (19.9 KB)
I don’t think culling a number of geometry will solve this problem.
Here, after I bumped up points to 20, I have to delete all the red to get the Solid Union done.

How did you get the number 1.38 mm? Is that calculated or you discovered it manually?

Besides short segments causing trouble, I’m convinced the coincident spherical ends are part of the problem why the boolean union fails.

Shortening all segments by a tiny bit creates a better situation for the boolean union. The ends are overlapping and never coincident.

voronoi3d_solid_union.gh (23.2 KB)

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Thanks all!

Martin Siegrist’s solution has the error in Extend Curve.
Is that not a problem?

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Look what the error message says.

Of course the perfect way would be to cull too short segments first…

You can also try the plugin “Dendro” if you don’t mind ending up with a smooth mesh instead of the Brep.

I think It’s very easy to use for this application.

Guide here:

btw if you want to tag someone in a post you can simply use @grs_1019 or @martinsiegrist