So in my Kinect + After Effects tutorials I offer a couple ways to rig the puppet’s head, but neither one is an ideal solution: the first one leads to occasional face-stretching and the second to increasing the manual animation workload substantially.
But there’s a better way! Put the anchor point in the center of the face, and attach the position keyframe to the Head control point. Then apply the following expression (based on one originally found here) to the rotation parameter:
this_point=thisComp.layer("Spine").effect("Head")("Point"); that_point=thisComp.layer("Spine").effect("Neck")("Point"); delta=sub(this_point, that_point); angle=Math.atan2(delta, delta); ang = radians_to_degrees(angle); (ang+90)%360+transform.rotation
Now the head will rotate to match to the angle formed by the head and neck points, but without the weird distortion the Puppet Tool can cause. You can tweak the head’s attach point by shifting the anchor point.
Kinect MoCap Animation in After Effects
Project files: Click here to download the After Effects project (CS5+).
Quick note: the text is just transcripts of the videos, so you can read or watch as you prefer.