Transcript Behavioral Animation

Behavioral Animation
Procedural Animation Type?
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)
– “boids”
Instead of animating individually, specify rules
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)
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Implies knowing about other members
Localized, not global so that flock splitting can
occur
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)
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?
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
Next Step
• Massive/crowd animation