Boids

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The simplest graphical objects to simulate the behavior of the crowd are boids, which were developed by Craig Reynolds in 1986, which simulates the flocking behaviour of birds. His paper on this topic was published in 1987 in the proceedings of theACM SIGGRAPH conference.

As with most artificial life simulations, Boids is an example of emergent behavior. The complexity of boids arises from the interaction of individual agents adhering to a set of simple rules. The rules applied in the simplest Boids world are as follows:

  • separation: steer to avoid crowding local flockmates
  • alignment: steer towards the average heading of local flockmates
  • cohesion: steer to move toward the average position (center of mass) of local flockmates

separation

alignment
cohesion

You can quite easily build such boids systems about rule such as avoiding collisions with external obstacles, escape from predators, moving towards a particular purpose, etc.

Illustration of the use of boids to simulate the behavior of the stock may be a scene from the movie The Lion King.

One of the simplest uses of boids are realistic models of fish, but the most interesting thing is to simulate the behavior of people, due to the complexity and intelligence.

Examples of software performing the collective behavior of objects are Autodesk Kynapse, MASSIVE, or DI-Guy. More about these programs, see the section Examples of tools. The implementation of the software you can see on the video below.

Summary

Boids allow to simulate animal herd behavior and crowd of people. Using three basic rules: separation, alignment and cohesion, realistically reflect the complicated motion of objects. Practical application for boids are an air traffic control safety systems, evacuation plans for buildings and of course the film industry.


Parent page: Where do we use computer graphics?