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Using weak referencing and transform spaces for unifying FK/IK.

May 19, 2007


I thought about an idea for unifying an fk/ik system today – using a single fk chain driven by a detached wrist to define a hypotenuse, to make it act like IK. And driving the same wrist with weak node referencing, and storing two matrix3 values driving its transform space so it stays glued to the end of the elbow joint. Rotation would use the same method.

So you would move the wrist, and in doing so define the 3 lengths needed for ik solution (2 of the lengths are constant unless you introduce stretching). And when you rotate the bones – on another float_list (bezier controller) you drive the transform positional space of the wrist, keeping it glues to the end of the elbow.

Weak referencing could also be used for gluing the knee control to the knee, and also a control at the elbow to break it, stretch it etc.

 Some issues maybe doubling of transforms, plus controlling the elbow. Also pulling the wrist too far from the the ik solution – this i think could be fixed.

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