Java Boids

The boids are modeled as point masses. A local 3D coordinate system (frame of reference) is attached to the point mass and made to align with its velocity. Based on its local environment, each boid's behavioral controller computes a steering force on each iteration of the simulation. The steering force and velocity are clipped if they exceed a certain threshold. In this demo the boids are contained inside a wrap-around sphere. When they venture outside of the sphere they are "teleported" to the opposite side of the sphere. Note that aside from randomized initial positions for the boids, this simulation is entirely deterministic. All the lifelike, unpredictable behavior emerges from the complex adaptive nature of the model.

This applet was created using the Cosmo Code 2.0 Java development environment. The 3D rendering is accomplished using a slightly modified version of a class implemented by Paul Haeberli for his Pure Java 3d applet. (BTW: Paul suggested that I point out that my applet ignores mouse input.) In the future I hope to provide a version that allows you to interactively adjust various parameters of the simulation. Thanks also to Xiaoyuan Tu and Roy Hashimoto who made significant contributions to an earlier C++ version of this demo.

Other boids-related applets

• 3D models
  • Conrad Parker wrote a very nice model of 3d flocking. In addition to basic flocking, these boids will occasionally alight and then arise again. The graphics include a painted background, flapping wings, and shadows. He also provides an explanation and pseudocode.
  • Steve Hughes wrote this 3d model of fish schooling in the presence of a predator. Includes a control panel. Source code is provided.
  • Schooling tropical fish by Bill Kraus at Digital Biology. Nicely modeled 3d tropical fish, allows adding/removing fish, includes occasional sprinkles of fish food. [new]
  • Three applets by Ishihama Yoshiaki (Stone): boid, boid2 and boid3. [new]
• 2D models
  • The four members of the Biological Model Simulation Project made several 2d models of "Schooling Tadpoles". One demonstrates basic schooling (with obstacle avoidance), the same with a predator, a version where you click the mouse to drop food, and a version with two independent schooling groups.
  • Task Gouda wrote this 2d boids model which includes ten parameters which you can set to adjust the functioning of the simulation (requires Javascript).
  • Helmut Lorek wrote a Java-based simulation of fish schooling which includes adjustable parameters. It is based on a model by Andreas Huth and C. Wissel. See also the ECOTOOLS page.
  • This boids swarm applet (with source code) was developed by Jawed Karim, Thomas Bak and Dan Durand as part of an interactive presentation on Artificial Life prepared for the ThinkQuest competition for students aged 12 to 18.
  • Rich Vanderwal (of Groovee Creatives) produced this 2d boids applet for Discovery Online for a feature called Its Alive. Notably it allows you to switch each of the three component behaviors on and off, as well as allowing you to adjust the size of the flock.
  • Jonathan Robbins (with help from David Leserman) built a boids applet and control panel. See also his report on the project for his 8th grade science class.
  • Matthew Caryl wrote a nice 2d Swarm applet which includes a control panel for adjusting parameters. The simulation also includes a voracious predator which the boids try to avoid. Includes source code.
  • Larry O'Brien wrote an article in InterActivity called Artificial Life Programming in Java which used herding as an example. The article came with source code but no compiled version. David Brogan of Georgia Tech kindly provided a compiled copy online. Note that I've seen this crash browsers.
  • Duncan Crombie's page The Examination and Exploration of Algorithms and Complex Behaviour to Realistically Control Multiple Mobile Robots contains related information and a link to his 2d flocking applet with interactive controls and source code.
  • Flock with obstacles by Simon Buckwell
  • Flocking with "V" formations in an applet based on a model from Gary W. Flake's book The Computational Beauty of Nature. (You need to select the boid demo on the top pull down menu.)
  • BoidModel applet by Tomohiro Orikasa, with source code (comments in Japanese).
  • Boids Flocking Behavior by Scott Robert Ladd, includes a control panel.
  • Boids Applet by Kazuhiro Yoshida ("moriq") uses color coding to indicate number of nearby flockmates for each boid.
  • Tadpoids by Phil Pocknell demonstrates herding under the influence of a predator in a situation very much like the interaction between a sheep-dog and a flock of sheep, such as in a sheep-dog trial. See also his Pest Control applet and his dissertation. [new]
  • Flock with Obstacles by Keith Wiley is a Java applet using an approach similar to his Mega Flies application. It allows to drop in obstacles with a mouse click. [new]
  • Les Boids en JAVA by Cadin Gildas features three "species" of boids flocking independently but avoiding each other. Provides control panels to adjust flocking parameters. [new]
  • Genetically Engineered Battle Boids (2000) by Joshua Lifton. In addition to a 2d herding implementation, this applet includes a mode where two flocks of "battle boids" engage in stylized combat. In addition, the battling boids can be put under the control of a genetic algorithm which gradually evolves their behavior based on their success in battle. Source code is available. [new]
    
    
  • Unlike the flock applets above, these swarms make no attempt to align with their neighbors, and so look more like insect swarms than bird flocks or fish schools:
    • Java Flies by Alex Vulliamy.
    • Floys by Ariel Dolan
    • Flozoids by Fabio Ciucci
    • Insectoids by Jagannathan Sampath (Can be used with Alias Power Animator, source is provided.)
    • Hungary Swarm from The Temple of ALife features swarming around obstacles.
    
    
  • Other related models:
    • Frog Queue by Maeda Mameo appears to be based on a follow the nearest leader rule, but I cannot read the Japanese descriptions. Source is included.
    • Race Boids by Allan deCamp, a variation on the boids rules to control a "herd" of racing cars. [new]

See also Applets for Neural Networks and Artificial Life by Akio Utsugi

Mac users: for better Java support, try the iCab browser.

Send comments to Craig Reynolds <cwr@red3d.com>
visitors since September 24, 1996
Last update: December 7, 2000