Wrong display of breps

Hello,

I have a definition with mainly GHPython components using the rhinoscriptsyntax library.

Often the polysurfaces are displayed completely wrong. In this case I lofted the cross-sectional polylines:

If I set the display quality to "High" it gets better but still has random mistakes:

When I bake it though, everything turns out the way it should:

This happens especially often when using trims.

Does anyone know what's going on and how to prevent it?

Cheers,

Max

Replies to This Discussion

Permalink Reply by David Rutten on December 18, 2015 at 5:07am

I suspect the creases in the surface are not treated as proper creases. When geometry is baked to the 3dm document then Rhino applies a whole range of algorithms designed to detect and repair quirks. One of the things it does is figure out whether a surface has a sharp crease running across it, and if it does it will split that surface at the crease and create a polysurface instead.

Surfaces with creases often result in lame meshes. Most components which potentially output creased surfaces actually perform this check as well, but if you're making the geometry yourself through code then perhaps you need to also split creases?

Permalink Reply by Max Marschall on December 18, 2015 at 5:32am

Hi David, thanks for the quick response.

I tried exploding it (was that what you meant?) but it didn't work. I noticed it returns True on IsBrep but False on IsPolysurface...what does that mean? In Rhino lofting like this would have produced a polysurface.

Permalink Reply by David Rutten on December 18, 2015 at 6:59am

You can try calling BrepFaceList.SplitKinkyFaces on the Faces member of your brep.

Permalink Reply by Max Marschall on December 18, 2015 at 7:02am

"SplitKinkyFaces" ^^ You guys are the best.

Thanks, I'll try with that.

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