Thanks again, ockham! I'll have to look this over carefully... Which reminds me, does anybody know why Tkinter isn't supported in Mac PoserPython? Strange, since Tk stuff works with the Python that ships with MacOS...

There was something in the Poser Python scripts about Callback examples, where somebody's muscles flexed. That would be worth looking into. Imagine the possibilities of creating, say, three morphs, having none of them at less than 70 degree bends, then blending through three in succession... Sounds like it could be great.