MAS models

Boids model

What is a Boid model?

Many kinds of bird form flocks. Sometimes, when looking up at the sky, you can see birds forming flocks in a variety of patterns as they fly.

How can birds remain as a flock in flight while simultaneously, and even instantaneously, changing direction?
How do they communicate with each other? Do flocks of birds perhaps have a boss or leader?


In answer to this kind of question, the world of computer graphics provided an unexpected hint.

  This model was announced in 1987 by Craig Reynolds, and the sheer realism shocked the world. The word “Boid” was created by combining “bird” with the suffix “-oid,” indicating likeness to an object.

  The Boid model is able to reproduce realistic flocks of birds in a virtual space using just three rules.

Reproducing flocking birds through simulations

 Boids move through space in accordance with the following three rules. The three rules are “collision avoidance,” “velocity matching,” and “flock centering.”
①Collision avoidance
    If there is another bird or object into which the bird might collide, move away so as to avoid a collision.
②Velocity matching
    Align velocity and direction to that of neighboring birds and imitate their movement.
③Flock centering
  Try to get closer to areas with many birds, so as to avoid becoming separated from the flock.
Crowds of people fleeing or attempting to escape from floods, etc., who follow the person in front of them.



Registration with artisoc Cloud is required to run the model.

Further reading


Craig W. REYNOLDS, 1987, “Flocks, Herds, and Schools: A Distributed Behavioral Model,” Computer Graphics, 21(4), July 1987, pp. 25-34.
[Keywords] Flocks of birds, Boid, multi-agent simulation


Katsuma Mitsutsuji (University of Tokyo) June 1, 2016

Boid model basic information

[Model title]: Boid Model
[Model designer]: Craig Reynolds
[Year model announced]: 1987
[artisoc sample model creation]: KOZO KEIKAKU ENGINEERING Inc. (Masaki Tamada, Toshikatsu Mori), Katsuma Mitsutsuji
[artisoc sample model creation date]: June 1, 2016