2009

Rotating the forearm along the X axis rotates the arm elements about an invisible axis
between the shoulder and wrist.
Balance: Spine
Biped uses only the spine, in conjunction with the center of mass, to maintain
the biped's balance. Because of this, rotating all of the spine or any one of its
links causes the horizontal position of the body to change relative to its center
of mass. These adjustments are performed in the center of mass's local reference
coordinate system, ensuring that the figure will rotate naturally about its
center of mass; for example, during flips in the air.
On the Motion panel
Key Info rollout on page 4367, you can turn this behavior
off by setting Balance Factor to 0.0 for corresponding horizontal center of
mass keys. The Balance Factor control is in the Body group on the rollout.
Independent Orientation:Arms, Head, Feet
Changing the orientation of a clavicle (the root Arm object) changes the
position, but not the orientation, of its corresponding upper arm. In effect,
the clavicles are a support from which the arms are suspended.
Likewise, the orientation of the neck changes the position, but not the
orientation, of the head. Although linked to the neck, the head typically
4246 | Chapter 17 character studio