In 1986, Craig Reynolds
created a computer model of flock
". In this, each "boid
" is guided by 3 steering behaviors: Separation
, and Cohesion
. This was presented at a SIGGRAPH '88, and has been used in Half-Life
, and Enemy Nations
- Separation is defined to steer each boid to avoid crowding, and collision.
- Alignment allowed each boid to steer toward the average heading of other local boids. Without this, the flock resembles a swarm of bees, or flies.
- Cohesion prevents the flock from dispersing by steering each boid toward the average position of local flockmates.
This is a stateless
technique. Each iteration requires no memory of the previous, which is advantageous when memory constraints are an issue.