I guess you've answered my initial question on whether anyone has made it work, and that would be a 'no'. I've tried primitives as masks and had some success, but that's with more conventional geometry (insides and outsides). With stuff like East Park it's almost impossible to know where the seams are, even in wireframe view, as they're only visible if you're facing them. Frankly, if I could be bothered to fix the geometry in a 3D app, I may as well build something new and be done with it.

I had read that light leakage at right angle intersections is a problem with firefly in Poser, but had wondered (hoped) that someone might have figured a work around. Seems not.

 

Cheers