If it's an indoor + outdoor scene and there is no lights in a room lightmass wouldn't work as well as a skylight. it's mostly trial and error and seeing what works best really.
The pants and the boots are done quite well so far! This is gonna be an interesting one. Just fyi you made a spelling error in the title of the thread.
Thanks for the reply EQ! I ran into a similar thing later and I am betting it is a triangulation error then. Still getting used to this wonderful program!
This error is not related to the TDR and can come from mdany places (not specifically Painter). Are you on a laptop? Could you attach a log file please?