The Assign Controller rollout assigns and appends different transform controllers to individual objects. You can also assign controllers in Track View.
Animation controllers are plug-ins that handle all of the animation tasks in 3ds Max. For a complete list of available animation controllers, see Assign Controller (Track View).
Example: To assign a TCB Rotation controller:
 Select an object.
 Select an object.
                Motion panel, click Parameters, and open the Assign Controller rollout.
 Motion panel, click Parameters, and open the Assign Controller rollout.
                (Assign Controller), choose TCB Rotation from the Assign Rotation Controller dialog, and then click OK to close the dialog
                  and accept the change.
 (Assign Controller), choose TCB Rotation from the Assign Rotation Controller dialog, and then click OK to close the dialog
                  and accept the change.
                  The default Euler XYZ Rotation controller is replaced with the TCB Rotation controller.