Speaker: Jovan Popovic
Affiliation: CMU
Date: 4/19/01
Time and Location: 4:15 PM, B11 Kimball Hall
Title: Motion Design in Computer Animation

The design of computer animation begins with an idea of how objects should move. Transforming that idea into a compelling animation, however, is a tedious task requiring artistry and skill. Physical simulation simplifies this animation task by generating realistic motion automatically, but to take advantage of simulation methods, the animator must define simulation parameters such as initial positions and velocities of objects. Just as the slightest difference in a die toss can affect the outcome, a small adjustment of simulation parameters can drastically and unpredictably change the resulting motion. Altering simulation parameters to design a motion is cumbersome and unintuitive.

I will describe two design techniques for intuitive control of physical simulations of rigid-body motion. The interactive editing technique allows the animator to design the entire motion by dragging a body, at any point in time, to a desired position. The off-line sketching technique allows the animator to design the motion of objects by acting out their motion with hand gestures. Both design tools take as input a description of how objects should move and output a physical motion that matches the description as closely as possible. For example, the animator could sketch a motion of a pencil tumbling in the air and landing in a mug by picking up a real pencil with an attached motion sensor and moving it in the desired fashion. The sketching tool would then compute the required simulation parameters and simulate the desired physical motion automatically.