Physically-Based Animation

Idea: to obtain a physically plausible animation, simulate the laws of Newtonian physics.

In contrast to kinematics, this is called a dynamics approach.

• Have to control objects by manipulating forces and torques, either directly or indirectly.
• Animated objects may be passive: bouncing balls, jello, wall of bricks falling down, etc.

Inverse dynamics is difficult

• Finding forces to move a physical object along a desired path
• Most current applications are ``passive'' variety
• Useful for seconary effects in keyframe animation:
  • a mouse character's ears should flap when it shakes its head,
  • a T. Rex's gut should sway while it runs,
  • a feather in a cap should wave when wind blows on it,
  • cloth should drape around an actor and respond to his/her/its movements,
  • a wall of bricks should fall down when a superhero crashes into it.

Caution: simulated secondary effects can make bad keyframed animation look even worse!