Motion rings for interactive gait synthesis

This paper presents a practical system for synthesizing gait animation in game environments. As well as improving the reality of animation, we should improve the efficiency and the maneuverability of the character, both of which are essential for interactive games. Our system supplies these practical demands by integrating a motion interpolation technique and a sampling-based control mechanism. We introduce a parameterized looped motion data structure, called a motion ring, for synthesizing a variety of cyclic motions. A continuous gait motion is synthesized by circulating through the motion ring while the interpolation parameter is adaptively controlled according to the terrain condition. The gait controller uses a sampling-based precomputation technique which efficiently searches natural foot contact on terrain of an arbitrary surface shape. The interpolation parameter is also controlled to obey the user control within the duration of quarter gait cycle. Although our system slightly sacrifices the physical correctness of the synthesized motion in order to quickly respond to user input, critical visual artifacts such as foot-skating and jerky movement are prevented. We demonstrate the efficiency and versatility of our integrated system by interactively navigating the character on complex, uneven terrain.