Quote - So it was reversed normals, as I said.

no, it's a double faced surface with a zero thickness.. and has been known about since Poser 5...
the fix in 5 was add a small amount of displacement, 6 and higher have the Normals switch.. Most render engines can allow for it.

and I'm suprised at the names in this thread that did'nt spot it.... as I said.. it's been known for years...