Ryan Tan

The 3 arm setup usually consists of 3 sets of joints which gives the animator fine control over IK/FK blending. The IK hierarchy would be used to animate with IK while the FK hierarchy would be used to animate in traditional FK. The last hierarchy would be the result of the two after blending the IK and FK animation, and is also used for skinning.

Split joints allow natural deformation when both bending and twisting are required on a joint. One good example is the elbow...