A realistic, natural-looking, flocking behavior (for example birds or antelopes or bats) can be created through creating collections of objects with the following four simple rules:
Separation: Avoiding getting too close to neighbors
Avoid Obstacle: Turning away from an obstacle immediately ahead
Alignment: Moving in the general direction the flock is heading
Cohesion: Moving towards the location in the middle of the flock
Each member of the flock acts independently, but needs to know about the current heading and location of the members of its flock. This recipe shows you how to create a scene with two flocks of cubes: one flock of green cubes and, one flock of yellow cubes. To keep things simple, we'll not worry about separation in our recipe.