Posing and animating using forward kinematics

As the last part of the lesson, you can optionally practice posing and animating the character by rotating joints that are not controlled by IK handles—the ball joints of the feet, and joints from the back_root through the upper_neck. Rotating such joints is forward kinematics.

With the exception of the back_root, you’ll invariably rotate rather than move the joints that aren’t part of an IK handle. If you move the joints, the bones lengthen. This deforms bound skin undesirably unless you are creating cartoon-like distortions.

Because you’ve already set keys for IK handles, some joint rotations on non-IK handle joints will be restrained by the IK handle positioning. If this interferes with the intended poses, you can remove all prior animation from an IK handle by selecting Edit > Keys > Delete Keys. You can also use Delete Keys to remove all animation from keys you’ve set with forward kinematics.