Hi,

I attached the gh file.

I have strange issue with mesh valid.

Basically I would like to change vertex position to other vertex position, but this causes invalid mesh

This one produces invalid mesh:

M.Vertices.SetVertex(n[j], M.Vertices[n[0]].X, M.Vertices[n[0]].Y, M.Vertices[n[0]].Z);

And this one is a good mesh

M.Vertices.SetVertex(n[j], M.Vertices[n[0]].X+0.01, M.Vertices[n[0]].Y, M.Vertices[n[0]].Z);

Why previous code line results in invalid mesh?

validity.gh (6.8 KB)