Oof!

So it turns out the coordinates for subdivision deltas are actually given with respect to the tangent space. The first coordinate is along the normal, the second seems to be the surface tangent that lies in the xz-plane, then the last coordinate is orthogonal to both. I'm assuming that makes it easier for the renderer to munch them up or something.

That's not the case for regular morph deltas, is it? They are just figure-space x, y, z, aren't they? It seems that I would have remembered if they were all fancy-like.

Also, is there maybe a parameter for telling Poser how to interpret deltas that I've forgotten about?

As I said, any day now...

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