UV mesh problem

I’m not able to generate a proper UV mesh from closed lofted fillet polygons.

The UV mesh is not proper at the surface seams (see image) while it appears proper in Rhino.

Workflow: generated loft in GH (see attached), export as MotionBuilder FBX (see attached), imported in Substance Painter.

I have tried for a few days now every option I could think of including explode poly, divide curve, etc. before loft, played with the mesh export parameters - all with the same results.

Looked at https://wiki.mcneel.com/rhino/meshfaq - nothing solved the problem

Any suggestions?

test 3.zip (274.8 KB)
UV mesh seam issues.gh (604.7 KB)

where is the problem with uv mapping ?

The problem is in the export to FBX and import into Substance Painter.
How did you generate your image? Was it made from the FBX file provided?
I would love your image in Substance painter :wink:
Inside Rhino things look fine.
Ideally it is just me a bad operator.

Yes i use your fbx file and there is no problem with uv mapping ; this is from blender

Wow, I may have been trying to fix something that does not need fixing :wink: It shifts the issue to why does Substance painter make it look so bad?
Could you resave the file for me from Blender and I’ll try to open it in Substance Painter?

this is from blender
shape.zip (508.5 KB)

Well, same issue from that file in SP
It is when I use the bake function in SP
SP is new to me - so it may well be operator.

Thank you for your posts. It made me look into different places for issues and now I see this in SP:

Not sure what it means yet or what to do about it.

i have no idea but this is problem with substance

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Thank you sir for getting me into a new direction for this issue. I’ll close this subject as resolved from a GH / Rhino perspective.

Thanks again,


try to remove duplicates vertices in blender and use obj instead of fbx ; may this fix your problem

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Did you tweak the “Mapping coordinates”. My SP guy says that my UVs in my file are not bad perse, they are just bunched together. Could you send me your .blend file and I have my SP guy take a look exactly you did to get it to work?

I just imported your fbx file in blender and added checker texture

Found it! Changed the ID from vertex color to object color based. Solved the issue.

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Thanks for working through this with me!