I see what you mean about joints- I'm used to working with a program that has numeric input- instead of grab and drag, you say x25, y56, z44 to... sort of thing. Curiosity can be educational, though! I was surfing around, and found a page for an up-and-coming (release in fall) program called Reflex-Drama, which seems to be based on biomechanical principles. And yes, there will be demos! (It claims that it will be compatible with major apps.) Here's the url if you're curious. www.reflex3d.com/drama.html