I've reached the conclusion that poles (3-edge or 5-edge) on any smooth curvy surface, like the buttock, are just a terrible area.  They will never be smooth.  At the hip line it isn't a big deal, because that's a bumpy, dimply area, but on the buttock it just does not work.  I had already mostly realized this along the spine and in some clothing modeling work in the past but it was a real pain to find a solution down the leg.  There are still a couple of poles around there but they're in the gravity fold and near a muscle crease so I don't think this will bug me any more.

Anyway, poles - never on smooth curvy surfaces!

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