Cannot change Mesh Model Material

Hello guys, I am having an issue with changing the material for the attached mesh model. Can someone give me a hand with this one? Is there a way I can change the colour and material of individual faces without “Rebuildmesh”? Thank you.

Mesh Model Material Issue.3dm (229.5 KB)

Hi @realtaiwanese,

Your mesh has per-vertex colors.

Rhino does not have a way of setting these, other than the ComputeVertexColors command.

Mesh vertex colors can be added, modified, and removed using a Python scirpt.

Where did the mesh come from?

– Dale

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Hi Dale, thanks for the prompt reply, we got the model from a client but I am not sure how it was created. In terms of the vertex colors, can these influence the colour of the “mesh surface” ? Do you have a link or site that explains this concept in more detail?



Hi @realtaiwanese,

Mesh vertex colors are not used in day-to-day modeling and rendering, as there is really no good way to set the values (most meshes have hundreds, if not thousands, of vertices).

The primary use, in Rhino, for mesh vertex colors is for false color analysis, CurvatureAnalysis for example.

That said, our mesh data structure supports mesh vertex colors. So it’s possible to write tools to populate this structure, or to import meshes from other file formats that also support mesh vertex colors.

If your curious what the colors are, then just run the attached script using the RunPythonScript command. (756 Bytes)

– Dale

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Thanks Dale, the information you have provided is very useful!