Steve "UVMapper" Cox solved the problem. He discovered the floor had three degenerate facets. Oddly, this was the only part of the prop that was brought in from the Poser Props Type subcategory -- the rest I made in 3DS max. Anyway, removing this floor prop, and reimporting the OBJ files with a new floor prop created in 3DS Max fixed everything. Thank you everyone for all your time and effort. And thanks especially to Steve, for finding the solution. azl