Mesh Trim Problems _ sometimes successful, sometimes fails?

Hey all,

I’ve spent quite a while looking through old forum posts as this has come up before, but none of the suggestions elsewhere have worked for this example.

I am trying to trim and cap a mesh; the input mesh has a bumped pattern on all faces - and I would like to replace some bumped surface faces with smooth ones.

  • I have the input mesh (with bump surface pattern all over) which is a good solid closed mesh
  • I have the pre-bumped brep surfaces which to use as the base geometry for trim and cap locations
  • I have been using those brep surfaces to create ruled surface planes which overlap the mesh

So far it is working successfully on some locations, but not others - despite using the same techniques all around.

Can anybody see any reason why this method is not working consistently, and perhaps suggest better methodology?

Any assistance with this would be greatly appreciated - it’s quite frustrating!


JJC. (1.8 MB)

Well, just in general, Rhino’s native mesh tools are weak, especially with complex meshes. As Grasshopper is calling the same code underneath as the native Rhino functions do, I would expect it to fail in the same sorts of situations… Not sure if there would be any GH plug-ins available to help here.

Are there any reasonable and reliable ways of converting mesh into brep for this type of operation, that you are aware of?

No, and it would be incredibly heavy as a nurbs. Use a mesh software. Something like Zbrush could chop that pretty easily.

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i can also recomend nettfab for any kind of mesh trimming and boolean operation :smiley: