mesh difference problem

I have made a script where I take the Voronoi component, smoothen the cells and my goal is to substract the smoothened cells from the Brep I used, so that the holes remain. The problem is that I use the Mdiff component and it doesn't seem to be working the way I want. Any thoughts ?

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Microstructure.gh, 10 KB

Replies to This Discussion

Permalink Reply by Hannes Löschke on January 4, 2014 at 12:02pm

Booleans only work with intersecting geometry. There is no such thing as a negative Rhino solid. So you cannot create a hollow box. You will always have two closed bReps, just one inside the other.

The same is probably true for meshes.

If you want a single mesh with inside and outside surfaces, you can just MJoin the Box and the cells.

If you care about normals, you could go ahead and flip the meshes for the inner cells, so the enclosed volumes are "outside".

Permalink Reply by Thanos Tk on January 7, 2014 at 1:16am

thank you for your answer. Is there any other way to substract the smoothened cells from the original geometry? I want to create a hollow box like the one in the image below

Permalink Reply by Hannes Löschke on January 7, 2014 at 4:07am

In your example, the inner cells are actually intersecting the boundary box. Yours do not intersect with the boundary. If the bounary and inner cells intersect, mesh difference would work the way, you expect it to.

Permalink Reply by Thanos Tk on January 10, 2014 at 12:04pm

is there any way to actually make them intersect? They dont intersect because they are meshes or because the boundaries of the cells dont reach the boundaries of the box? I am a grasshopper newbie sorry for my noob questions...

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