Bug: Solid Intersection deletes elements completely enveloped

There is a bug in GH, where if you use a Solid Intersection with several elements (A) in one set, then all the elements that are completely inside the other element (B) will be discarded, whereas in Rhino they are kept when using the same operation.

This could maybe be an option in GH to select between discarding and not discarding them.

Note in the image below the result from Rhino on the left and GH on the right.

The only way to get them back right now in GH is to do a Brep | Brep check and get the ones that have no intersection line back, but this could still leave the ones that are completely outside B, so its not a good solution.

Attachments:

union_intersection_bug.gh, 5 KB
union_intersection_solution.gh, 8 KB

Replies to This Discussion

Permalink Reply by Daniel González Abalde on October 28, 2015 at 10:31am

You already have the solid which is inside in a previous component.

Permalink Reply by Armin Seltz on October 28, 2015 at 10:35am

Yes I know that. This is just an illustration of the problem. I am using this in a case where I am using more than 2 elements and they are in one big set of elements, where I can not do this "by hand" as you suggest.

Permalink Reply by Daniel González Abalde on October 28, 2015 at 11:06am

I have not suggested doing it by hand, you have components to see if an object collides with another.I'm not judging that you prefer to return the objects that do not interact, but also do not think that this is a bug. Boolean operations work only when they are touching.

Permalink Reply by Armin Seltz on October 28, 2015 at 11:19am

Well in that case the bug is in Rhino, because that is exactly what Rhino does (as shown on the left).

If we are talking about Solids I very much think that an intersection also includes something that is completely inside, because they do intersect. Meshes are hollow inside, but solids are not.

Either way its strange that Rhino and GH behave differently and an option in the GH component would be an easy fix.

Permalink Reply by Daniel González Abalde on October 28, 2015 at 11:59am

Well, it's Rutten who knows why he did so, but it is not an error I think, Rhino simply does not remove it, I guess that's more advisable modeling sequentially. Solid objects are not really solid, are representations of their boundaries, meshes can do it in the same way you can have two separate meshes being the same mesh-object, but with polysurfaces can not because the intersections only work on contact, at least for now.

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