hi all 
im working on an interior animation, multiframe imap and LC. model is -hm- from sketchup. but ive cleaned it, best i can, of all visible double faces (there are still some on outside walls or internal surfaces.. its a right pain to clean) model renders perfectly clean in all other shots.
anyway i get a dirty streak on one of my clean white walls. its always in the same place. the geometry there is a single polygon, totally clean. there are no other bits of rogue geometry in that location.
the strange thing is if i do a small region render, its not present. when i do a full render,or a large region, its there. as you can see its viewed through glass. the glass has a non refractive green vray mtl for the edges to enhance the look.
the glass object is set to not generate or receive or be visible to GI. gi and photon caustics are turned off. i have secondary ray bias set to small value (0.001) (is this in scene units? scene is set to inches, with visible units set to mm.. dont ask.. its not my model.)
its visible in the imap precalc, but not in the lightcache.
any ideas? worst case i can do a small region render of the frames where its visible and patch it in (although the gi -never- matches on a region calc.. need some feathering in. hope i can make the region big enough. ) , anyway, id prefer to know what the heck it is…
