In This Virtual Fish Tank, You Make the Rules

In my last post, I discussed how individuals following simple rules cause cause coordinated group behavior to arise. The boid model created by Craig Reynolds used three rules – alignment, separation, and coherence. But how much attention does each individual pay to each rule? In situations like migration, alignment might be the most important rule. If you’re being attacked by predators, sticking together and paying attention to the coherence rule might keep you from being eaten.

Clearly different situations might have different approaches. I was very interested in how different weightings of these rules might behave, so I decided to create a program that would allow you to change the relative importance of each rule at will. You can see a video of it in action below (the three sliders on the bottom left control the influence of the various rules).

Smaller screen, older computer, or just want something more simple?
Load the standard definition fish school simulation.
Big screen, fast computer, and want to give the fish some more room to swim?
Load the high definition fish school simulation.
Alignment: This slider adjusts how much each fish wants to head in the same direction as other fish around it.
Cohesion: This slider adjusts how close each fish wants to be to its neighbors.
Separation: This slider adjust how much each fish wants to space itself out from the others.
Click anywhere in the water to add a new fish.
Press this button to reset the simulation.

I hope you enjoy it – please leave me a comment if you have any questions, comments, or find any bugs.

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