Abstract: An interactive avatar display system provides a computer-generated view of a virtual space including an avatar that moves in the virtual space in response to movements of the user that are sensed by sensors. The number of sensed movements is less than the number of degrees of freedom of avatar movement. The interactive avatar display system computes an array of accelerations to apply to movable body parts of the avatar and computes the array of accelerations by solving equations of motions from masses of the movable body parts and an array of forces computed from an array of inverse dynamics force values for the movable body parts and one or both of an array of balance control force values or an array of locomotion control force values, taking into account a set of constraints for the avatar, and possible also environmental objects in the virtual space.