December 28, 2006
Essentially the ideas of combination sculpture: to model a series of poses and corrective poses that exist in a space governed by wieghts can be applied to any rig – including bone and muscle rigs. All your doing is making poses and corrective poses.
The math behind corrective poses can ofcourse be script so it becomes a simple task of making the combination look right, and behind the scenes do that math to make the corrective shape. For bone and muscle type setups, you’d need ways of storing all transforms of all the joints/controls used in the face as if they were verts and do some corrective transform math to build the corrective pose.
As to making the poses, there seems to be some governing rules, for one, the order of making the corrective shapes. Take for example an n-space of 3 (basically a point3 space, 3 dimensions) , essentially three sliders – we have around 7 poses existing in this space: [1,0,0], [0,1,0], [0,0,1], [1,0,1], [1,1,0], [0,1,1] and [1,1,1]
The last [1,1,1] has to be built last, because it by it’s very nature is the combination of everying, and likewise [1,0,0] , [0,1,0] and [0,0,1] should be made first as there the initial single poses. What happens between these is the tricky part , and especially [1,0,1]. [1,1,0] is a simple extension of [1,0,0] – so deducting from that [1,1,0], [1,0,1], [0,1,1] should be the order, we model the corrective poses.