The underlying coordinates of the geomtrical object you use are what is driving the Fractal_Sum. So if you load a one-sided square, scale it or move it, export it as obj, and re-import it as a new prop, you will see a difference. But all that means is the model coordinates influence the presence and location of the artifacts. That doesn't tell you why they happen, where they happen, or how to get rid of them.

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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)