No Intersection between these 2 surfaces

Getting weird/no results with these 2 surfaces. For some reason Rhino doesn’t find any intersections between them. Looks like a bug to me.

220422 IntersectionProblem.3dm (334.7 KB)

The Rhino model shows this:

Oops, uploaded the file from my other topic.

Edit: Now the file should be the correct one

Running rebuildedges on those surfaces fixes the problem

How did you create the surface with the two slits in it?

At the gumball location I selected 4 surface points which seem to be coincident.

Actually there are two “isocurves” with 4 coincident surface points.

@martinsiegrist To be honest, I don’t know how this surface was created. It’s a file I received from a client that’s causing issues with the plug-in I’m making for them. Trying to debug it I saw I cannot trim them and then realised I also cannot find an intersection between them.
RebuildEdges is something I’ve never had to use, and also didn’t know it existed. I’m a bit confused by why it’s needed as well.

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The surface is planar and has way too many isocurves for a planar surface.

_Dupborder and looking at the control points of the curve also shows way too many control points.

I think you should duplicate the border and run _FitCrv to create a clean border with Degree=2.

Then _PlanarSrf

The result is a clean, planar surface.

220422 IntersectionProblem.3dm (335.3 KB)

PS: _RebuildEdges might get you an intersection but the surface is still bad.