   skeletal animation math
  I want to know the math behind skeletal animation to create my own animation system and ragdolls. I know it's matrices but i.e. I don't know how to calculate a matrix to move from 1 animation to another, for smooth transitions.Any book or tutorial that would explain this?   
  Do you use quaternions to describe joint rotation?I might be wrong on this, but It might be easier to interpolate quaternions and turn them into matrices as soon as you need those. As far as i know, this is how skeletal animation is generally implemented.Maybe this will be usefull:http://www.gamedev.net/community/forums/topic.asp?topic_id=474656   ;  Thanks for your reply!The article referred to in that thread seems very interesting and could probably help me with my problem.   ;This might get you started. Keep everything as Pos+Quats for as long as possible (i.e. you can't blend matrices unless you convert them back to pos+quats). If you can interpolate between 2 key-frames, you can interpolate between 2 animations....   