More subtly, but no less importantly, during simulation the active input yields visible secondary effects,such as physically based slipping which is far more desirable than kinematic-based,motion capture foot skate. Sometimes physically based slipping is appropriate, when a reaction calls for a fast corrective change in stance for example. Likewise, desired changes in momentum can be excited through active control, such as throwing out an arm or a leg for balance for example. These physically based characteristics can change the resulting motion in a manner consistent with the upcoming motion, but are only achievable if the simulated character is actively moving in anticipation of the “chosen” response in addition to passively responding to the collisions happening based on the current interaction.