Synthesis of Complex Dynamic Character Motion from Simple Animation
We present a general method for rapid prototyping of realistic character motion. We solve for the natural motion from a simple animation provided by the animator. Our framework can be used to produce relatively complex realistic motion with little user effort. We show that realistic motion can be achieved by enforcing a small set of linear and angular momentum constraints. This simplified approach helps us avoid the complexities of computing muscle forces. Simpler dynamic constraints also allow us to generate animations of models with greater complexity, performing more intricate motions.
Paper
Liu, C. K. and Popović, Z. Synthesis of Complex Dynamic Character Motion from Simple Animation ( ACM SIGGRAPH 2002 )
Video
A jumping motion with sharp turns. The simple input motion only contains 5 keyframes .
A gymnastic handspring motion. Positional constraints are detected both on the feet and the hands .
A high-bar motion with a handstand at landing. The same algorithm applies to both ground-contact and bar-contact stages.
A hopscotch motion containing hops, broad jumps, and a spin jump. Each hop only contains 3 keyframes in the input motion.
A running motion sequence. The upper body is completely stiff in the input motion.
An ice-skating motion with an 180-degree turn in the air. Sliding constraints are detected at the ground-contact stages.
An karate kick motion created by an iterative optimization process.
A “Russian split” in figure skating. One keyframe at the midair is added to refine the ice-skating motion
A hopscotch motion performed by a child character with heavier head and short limbs than the adult character
The character’s left knee is stiff when performing a broad jump
A zig-zag leaping motion performed by a three-legged monster
A three-legged monster performing a spin jump
Project members
This research is supported by
University of Washington Animation Labs
National Science Foundation
Electronic Arts
Sony
Microsoft Research