Skeleton Setup - Game Character Development with Maya - page 660

Note
You can alter any of these settings after a joint has been created.
Degrees of Freedom dictates which rotations are active. Disabling X, Y, or Z will
remove the ability to rotate around that axis. Disabling some axes can be done, for
example, on an elbow joint, where you would want to rotate around one axis and
not the others.
Scale Compensate (when enabled) automatically scales other joints in the same
skeletal hierarchy when you scale joints above them. The default setting for this
option is enabled.
Auto Joint Limits lets Maya specify how far a joint can rotate around its axis.
Create IK Handle automatically adds IK (Inverse Kinematics; see Chapter 12 ) to
your character's joints as you create them. As tempting as this option might seem
at first glance, it's rarely a good idea to use it.
Auto Joint Orient determines how the axis on each joint will be set. In the default
setting (xyz), X will always point down the bone. Y will attempt to point up, and Z
will try to point out to the front (the Y and Z axes' positions are determined more
by the orientation of their child bones than the effect of this setting).
You can see the effect of the xyz Auto Joint Orient setting demonstrated in Figure
11.2 . In this example, there are two joints, and in the center of each you can see the
joint's rotational axis: X pointing down the bone toward the next joint, Y pointing
up, and Z pointing out to the front.