Hey! **piz99**, if you wander by, did you notice that the Render FireFly script allows you not only to set the raytrace and IDL bounces independently, but also allows you to render using *only* the IDL? This looks like a very clear way to locate where the splotches will appear and maybe get some feel for what is going on. From my one example so far, I would guess the splotches are minimized if there is a fair amount of direct light competing with the indirect light around the splotchy areas. More research!

Whichway

P.S. - You can time your renders as well!
P.P.S. - I have no idea why it failed to render the second block. It's transparent, not white.

[Before you ask, it's part of the Poser 8 content at - C:Program FilesSmith MicroPoser 8RuntimePythonposerScriptsScriptsMenuPartnersDimension3DRender FireFly.py]