1. Behavioral Animation Procedural Animation Type?

2. Behavioral Animation Introduced by C. Reynolds (1987) Animating many things at one time –A group of the same species (flock of birds, school of FISH ) FISH –“boids” Instead of animating individually, specify rules

3. Behavioral Animation Two main forces control group: 1.Collision avoidance- each member must avoid collision with other members and the environment 2.Tendency toward group centering (staying together) Implies knowing about other members Localized, not global so that flock splitting can occur

4. Additional Forces Velocity matching of neighboring boids (like merging on a freeway) Attraction/repulsion (like bees attracted to sweets) Behaviors –Migration –follow-the leader (leader has pre-scripted path) –Predator-prey(two species or additional actor)

5. Resultant To determine resultant vector, don’t use averaging. Instead, use priority allocation based on finite (normalized) resource A boid is moving through a force field. Assume that the boid’s trajectory is determined 75% from current trajectory and 25% from external forces. If the current trajectory is (1,1,1) and the external force is (0,2,0), what is the next trajectory after one time step?

6. Perception Boid aware of itself and 2-3 neighbors See what’s ahead of it within limited field of view –Distance visible in front is limited –Influenced by objects (obstacles, force fields) based on distance & size

7. Next Step Massive/crowd animation