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Looking at the foot has made me wonder: why does the Twist parameter point on Z, and not Y?  I've seen this in other figures, too, and it's always baffled me a bit, given what the twist deformer actually does.  Does this rotation axis ordering for feet have something to do with the Walk Designer?

Which figures have you seen this in? I just had a quick look at Alyson and V4, both of which use the YZX rotation order for the foot, like Antonia does, but unlike Antonia use the name 'twist' for the Y axis, which is in agreement with Poser's internal conventions.

With that axis order, the Y axis is the one that gets the twist deformer. I just decided to change the external names because the Z axis is really the one that twists the foot, even if Poser doesn't see it that way. The Y axis twists the shin.

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