I had a look at the UV MEL commands and there doesn't seem to be anything to easily query for overlapping. I take it you'd want this for prepping for baking? Is it safe to assume that the overlapping UV part is identical to the underlying one when it comes to shape and UV-space-position?
It's not about how to actually do it manually. I should have mentioned more clearly in my first comment that I'm interested on how to query this in mel :( It's just that with some meshes that have flipped overlapped UVs, not all flipped shells are easily selectable in the 3d view as they aren't always on the same side and…
Then a simple workaround that might work is if you could check the centered pivot for each shell, and check for shell pivots that are on the same location (with a small tolerance). This would find stacked shells given that they are in fact neatly placed on top of each other. Then you might work on a solution to figure out…
I've tried to find a way to tell whether the UV shell is flipped or not but couldn't find any. There's an error in the Maya help file for the polyEvaluate command in the mel section. It states that for the -boundingBox2d flag, the mel command will return the UV coordinates for the bounding box as 4 float values in Mel and…