Quote - From what I've experienced, the problems with polygon smoothing and the indirect lighting artifacts pops up where you have concave geometry facing the camera (you can see it in that accoustic foam-lookin sheet I rendered earlier, and also in the backdrop prop).  Convex geometry doesn't seem to have problems.  I have no idea why.

edit: heh ^^ yes.

I know why, I think. Remember that shadows see the original un-curved polygon, while what is being rendered is a displaced point on the polygon. If the displacement is negative, as happens only with concavity, then the point being rendered is UNDER the original un-bent polygon. Thus, it shadows itself.

An interesting experiment would be to apply a uniform positive displacement in addition to the smoothing. If the uniform displacement was larger than any smoothing-induced negative dispalcement, then the displaced surface will always be "above" its original position. Self-shadowing should not happen in that case.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)