Quote - The most serious problem that found is to find where are the seams of the same material.

I agree, but that's not too bad, either. One has to find out where polygons share edges and then compare the uv indices on both sides. That could be a big performance hit if done "on foot", but Python has these nice, very fast built-in hash tables, so it shouldn't be too much of a problem.

-- I'm not mad at you, just Westphalian.