[BUG] To be able to _WeldVertices of a mesh converted from SubD you need to export and import as OBJ

Rhino SubD
, , ,
3

Yes I have done that inside the bug report:
https://mcneel.myjetbrains.com/youtrack/issue/RH-58199

SOLUTION
In Rh6, export the mesh as OBJ and Import it.
Now try again to weld with the imported ones.
Often that fix the problem

The starting mesh was invalid,
But exporting as OBJ and reporting it fixed that problem
At the end of the video, I try to fix the invalid surface.