Sphere collide, solid point collide brep - two behaviours

This definition produces two distinctly different results, depending on the brep used as input.

Brep1 correctly fills with spheres, whereas the spheres in brep2 hug the surface, leaving the interior void.

I’ve tried varying the sphere radi, number of points, method of generating points to input, meshing and re-meshing the breps, etc – nothing works to fill brep2 as intended. Can anyone explain what’s going on here?

The difference between brep1 and brep2 is a fillet along one edge of brep2.

This definition works with Kangaroo version 0.099

I've noticed the same discrepancy in filling behaviour when using version 2.02.

Attachments:

sphere-collide-breps.3dm, 138 KB
sphere-collide-comparison.gh, 28 KB

Replies to This Discussion

Permalink Reply by Daniel Piker on April 6, 2016 at 2:49am

Hi Michael,

The SolidPointCollide goal is actually always using meshes internally. If you supply it with a Brep, it will get automatically meshed. If you are getting strange behaviour, it can help to do this meshing yourself first, so you can check that it is a proper closed manifold mesh. When I used the default Grasshopper mesh settings on your solid, I noticed that it was producing an open mesh, even though the Brep is closed.

Permalink Reply by Michael Oost on April 6, 2016 at 11:22am

Hi Daniel,

Thank you so much for your reply. Following your suggestion, I meshed brep2 in rhino before setting it as a mesh in grasshopper - now the definition works perfectly.

Kudos to you for your amazing work - really, I'm honored to have received help from you directly.

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