Spanki,

I agree that it's a mystery why Poser is , I think,  using this infomation for shading. I don't see what purpose it serves that the face normals don't already provide.

I looked at the example file that TheOwl posted   plCylobj.txt on the first page of this thread. Following the trail of vt references through the face definitions I see a pattern for the triangles of the end caps and for the quads of the cylinder sides. In a couple of places this pattern is broken, particularly clear on the cylinder sides. I suspect that this is where the artefacts appear.