Having trouble with MeshBooleanSplit

Hello, total newbie here. I am trying to split a mesh, horizontally along it’s length (I need two halves of the key split lengthwise). I am using the MeshBooleanSplit command. It allows me to complete the operation, but the mesh does not split.

*I have been doing tutorials and learning and have able to split other objects successfully, I am just stumped on why this one won’t work.

Any help would be greatly appreciated :smile:

NEW_KEY_V3_forum.3dm (2.7 MB)

Hi Geokov- the mesh has some problems -it has some self-intersections, and also, though the mesh is still valid, it has some very very skinny triangles - aspect ratios of over 1000. My guess is it is the self-intersections that are problematic. If the object is symmetrical, then you can simply ExtractMeshFaces and window carefully in an elevation view right up to the symmetry plane - then delete these faces, mirror the rest and Join.

OK, I see some polygons cross the center plane, so it may be a bit more work.


Thank you for the help. Unfortunately, these repairs are a little out of my skill level. Back to the books!


Hi Geokov-

NEW_KEY_V3_forum_PG.3dm (1.7 MB)

Here is a fixed up version- just FYI, it did take a fair amount of hand surgery to clean up.

  • ExtractMeshPart to separate the flatter parts from the roundier bit.
  • CutPlane (planes are on their own layer in my file) to MeshSplit the results. Each individual part splits cleanly… not sure what that is about.
  • Join and delete as needed to make a half-key.
  • The fill the gap on the cutplane - this is the nastiest bit you need to bridge across in a number of places to break the opening up into relatively small chunks using PatchSingleFace and then FillMeshHole.
  • clean up further with UnifyMeshNormals, and CullDegenerateMesh Faces and then MatchMeshEdge.
  • Phew. Check Help for info on these commands - they will all be very useful if you are going to manipulate meshes in Rhino.
  • The mesh still has self intersections - this is in the original mesh, I do not know if there is any consequence for you down stream in your process, but just be aware…


Wow, that was extremely kind of you :slight_smile: I will be sure to read over everything very carefully and study what you have done. Thank you for the lesson and for your generous assistance.