Attached Link: http://www.renderosity.com/messages.ez?Form.ShowMessage=760796

If it isn't normals or welding, then the only other thing that it is likely to be is triangulatioin. Follow this link for an example. Sounds like this is what you are seeing. Poser is very sensitive to vertex rotation order (the sequence in which the vertices are enumerated in the file) By changing the sequence of 4 points (which describe two adjacent triangles) you can alter the location of the one common side, then the renderer does not get confused on the shading.