The extra bits I learned and implemented in the rig:
- How to rig a biped character, including setting up the hierarchy and constraints for the controls and what bones to place where.
- How to set up the reverse foot lock so that he can roll on the ball/toes/heel.
- Creating a setup where the animator can switch between FK and IK allowing for greater control of the arms. Three sets of arm bones were created, one for FK, one for IK and one which blends between these two to hold the geometry.
- Adding a twist system for the wrists and legs to avoid mesh pinching when the wrist/ankle are rotated.
- Using extra bones in the knees and elbows to maintain volume when the arms and legs are bent. These extra bones find the average angle of the bones on either side of it to orient themselves in the correct direction.
- Using clusters to control deformations on the face.
- Facial controllers that will follow the deformations caused by the jaw while still allowing control over the shape of the mouth AKA the "dorrito effect".
- A constraint system led by custom attributes on the controllers for knee/elbow/eye controllers to follow parts of the rig or be free in world space.