I can't do MeshSplit

I have a mesh with only faces and I tried to MeshSplit a line at the fold of the face to split the yellow part of the image, but I could not.
Do you know why?

split.3dm (328.0 KB)

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Hi Tatsuya - I see that does not work - thanks; for now use ExtractMeshPart in this case.

@tatsuya - also, that mesh has some very skinny, zero area polygons along the edges you are trying to split.



Hi Pascal,

Thanks for the verification.
How can I know where the very skinny, zero area polygons are located?

Hi Tatsuya - ExtractMeshFacesByAspectRatio - use 1000 or even more as the aspect ratio.


Thank you very much.
I tried using the command you gave me to extract and remove the very thin, zero area polygons and then MeshSplit again with lines, but it did not work.

Are there any other problems?

Hi Tatsuya - I see that - a cleaned up mesh does not split with the lines - I’ll add this to the bug tracker…
RH-81394 MeshSplit test case


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Thanks for adding it to the bug tracker.
I’m glad you can find the cause of the problem.

A surface used as a cutting/splitting tool, is the best workflow for cutting/splitting meshes – imo.

The cause of the problem is that the curve needs to be projected onto the mesh. The projection is vertical so the resulting cutters look like this, sending the cutter tight down into the mesh below. So that small split area is a result of the split.

To work around this, using extruded surfaces as a splitter gives Rhino enough information to correctly split the mesh. Although those extrusion cannot be vertical as they slightly miss one of the interscetion that. So these example below does not need additional projection: