EigenSkin: Real Time Large Deformation Character Skinning in Hardware

• Joint Support: a set of vertices that have to move to accomplish the animation of a bone.
• Eigendisplacement:
• Starts with a process called "skeletal subspace deformation."
• Still requires a good set of bone weighting as per traditional bone animation.
• Joint supports are made by moving a single bone to its extremes, possibly correcting vertices so the motion looks natural. The set of vertices which have been moved more than some threshold are the joint supports for the bone.
• Displacements of vertices are placed in to a giant matrix.
• Principle component analysis is performed to determine the most important displacements to accomplish particular movements.
• An interpolation curve is then made to derive the displacement for a joint based on the bone's rotation.

Since eigendisplacements come from principle component analysis, each one layers on top of the previous one to increase accuracy. You can use more or less layers to trade off accuracy and speed.