I was going to write the same, RH, but then while explaining the big difference between linear interpolation of a set of displacements (what a morph does) versus rotation, I suddenly realized something.

It is possible to implement a true rotation using a pair of orthogonal displacement morphs. You simply use a weighted sum of the two morphs based on sin(a) versus cos(a), where "a" is the rotation angle of a joint. One might call it a double-joint controlled morph, or DJCM.

As far as I know, I'm the first person to ever mention such a thing. 

Once I started thinking how that could work, it became clear to me that a DJCM can do things that cannot be done with weight mapping. 

So I decided that if I could think of it, probably somebody else did, and I should not say what weight mapping can do that JCM cannot. Because I'm pretty much convinced that DJCM can do even better than weight mapping.

For example, I think to truly simulate the movement of clavicle, collar bones, scapula, etc. or perhaps the strain of tendons against skin, you would do it best with DJCM, not with weight mapping.

But I'm not a morphing or rigging person - just thinking about these things from first principles.

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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)