Pretty self-explanatory topic, I guess... :smile:

I'm trying to write a script that makes PMDs for subdivision morphs. The tricky bit is that the deltas do not encode displacements in the x-, y-, and z-direction like regular deltas, but they are given with respect to a local coordinate system that is different for each vertex.

The first direction, let's call it n for normal, is an approximation of the vertex normal. It can be a bit off, which could be a hint that it's interpolated rather the re-computed from scratch.

Of the remaining directions u and v, it seems that one always goes along an edge that's incident to the current vertex. How that edge is chosen, and how it is determined whether its direction will be u or v, I don't know.

I'm still experimenting and hope to find out more in time, but if anyone happens to know the exact method that's used for this in Poser, I beg you to have a heart for a poor confused mathematician and tell me.

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