Boids – 2D Unity Approach

Boid’s model was created in 1986 by Craig Reynolds to simulate the behaviour of birds as they group together in a flock. The model has three key methods to mimic real life bird flock behaviour. These methods include:

a) Maintaining a heading based on the averaged direction of surrounding boids.
b) Maintaining a separation so boids do not overlap.
c) The boids must maintain a cohesiveness with the flock by steering towards the centre position of surrounding flockmates.

The behaviour also operates similar to schools of fish or other wildlife. As a game developer, this can be useful when implementing enemy mob behaviour and in my case, I used this approach to simulate flocks of zombies in 2d space as seen in the mp4 above.

The concept isn’t too difficult, below I’ve posted two implementations. I’ve implemented it using rigidbody2d but I’ve also included the code for using it without rigidbody force.

  1. Boid Class for use with Rigidbody2D
  1. Boid Class for use with kinematic