Boids is an
artificial life program, developed by
Craig Reynolds in 1986, which simulates the
flocking behaviour of
bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s, and related group motion. His paper on this topic was published in 1987 in the proceedings of the
ACM SIGGRAPH
SIGGRAPH (Special Interest Group on Computer Graphics and Interactive Techniques) is an annual conference centered around computer graphics organized by ACM, starting in 1974 in Boulder, CO. The main conference has always been held in North ...
conference. The name "boid" corresponds to a shortened version of "bird-oid object", which refers to a bird-like object, as well as referencing the stereotypical
New York pronunciation of 'bird' as .
Reynolds' boid model is one example of a larger general concept, for which many other variations have been developed since. The closely related work of Ichiro Aoki is noteworthy because it was published in 1982 — five years ''before'' Reynolds' boids paper.
Model details
Like most artificial life simulations, Boids is an example of
emergent behavior; that is, the complexity of Boids arises from the interaction of individual agents (the boids, in this case) 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 towards the average position (center of mass) of local flockmates
More complex rules can be added, such as obstacle avoidance and goal seeking.
The basic model has been extended in several different ways since Reynolds proposed it. For instance, Delgado-Mata et al. extended the basic model to incorporate the effects of fear. Olfaction was used to transmit emotion between animals, through pheromones modelled as particles in a free expansion gas. Hartman and Benes introduced a complementary force to the alignment that they call the change of leadership. This steer defines the chance of the boid to become a leader and try to escape.
The movement of Boids can be characterized as either chaotic (splitting groups and wild behaviour) or orderly. Unexpected behaviours, such as splitting flocks and reuniting after avoiding obstacles, can be considered emergent.
The boids framework is often used in computer graphics, providing realistic-looking representations of flocks of birds and other creatures, such as schools of fish or herds of animals. It was for instance used in the 1998 video game ''
Half-Life Half-life is a mathematical and scientific description of exponential or gradual decay.
Half-life, half life or halflife may also refer to:
Film
* Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang
* ''Half Life: ...
'' for the flying bird-like creatures seen at the end of the game on
Xen, named "boid" in the game files.
The Boids model can be used for direct control and stabilization of teams of simple unmanned ground vehicles (UGV) or
micro aerial vehicles (MAV) in
swarm robotics. For stabilization of heterogeneous UAV-UGV teams, the model was adapted for using onboard relative localization by Saska et al.
At the time of proposal, Reynolds' approach represented a giant step forward compared to the traditional techniques used in computer animation for motion pictures. The first animation created with the model was ''
Stanley and Stella in: Breaking the Ice'' (1987), followed by a feature film debut in
Tim Burton
Timothy Walter Burton (born August 25, 1958) is an American filmmaker and producer. Known for popularizing Goth subculture, Goth culture in the American film industry, Burton is famous for his Gothic film, gothic horror and dark fantasy films. ...
's film ''
Batman Returns'' (1992) with computer generated bat swarms and armies of penguins marching through the streets of Gotham City.
The boids model has been used for other interesting applications. It has been applied to automatically program Internet multi-channel radio stations. It has also been used for visualizing information and for optimization tasks.
Biologist
Richard Dawkins
Richard Dawkins (born 26 March 1941) is a British evolutionary biology, evolutionary biologist, zoologist, science communicator and author. He is an Oxford fellow, emeritus fellow of New College, Oxford, and was Simonyi Professor for the Publ ...
references the Boids model in his 2009 book ''
The Greatest Show on Earth: The Evidence for Evolution''.
See also
*
*
*
*
References
External links
Craig Reynolds' Boids page“Boids Demo Reel”Early motion tests, 1986 to 1987.
“Stanley and Stella in: Breaking the Ice”1987. On Internet Archive (remastered in 2023, highest quality. Also available o
YouTube)
JavaScript implementationJavaScript implementation with Phaser Framework3D Boids Simulation using OpenGL, used by the BBC's Natural History UnitLive In-Browser 3D Simulation of Bird Flocking Behavior in Unity3D– Open Source implementation for Windows, Linux and Mac
UNIX+Windows open source implementation in C++, using OpenGL and simulation controlsA java implementation using the javafx API* GLSchool - part of
XScreenSaver software
{{collective animal behaviour
Artificial life
1986 software