Flocking and Swarming

How would you animate a flock of birds all randomly moving about but having the same goal: to reach a specified target? How about a swarm of bees flying around a bee hive? Simulating such behavior is the purpose of Flocking and Swarming.

• Clone: Makes a copy of this controller. All parameter values and envelopes are copied.
• Delete: Delete a controller from the Controller list.
• Activate/Deactivate: This activates or deactivates the controller from having any effect on the simulation.

• Name: The name of the instance
• Affected Particle Groups: The groups of particles that are affected by the Flocking and Swarming controller.
• Min/Max Acceleration: Particles tend to accelerate when trying to reach their goal. The Min/Max Acceleration allows you to define a range of acceleration values for each particle, creating a more random, natural effect.
• Min/Max Goal Radius: The Minimum and Maximum Goal Radius values create two spheres, one inside the other. The particles see the region between these two spheres as their target destination, and this becomes their goal. This is the region the particles will flock and swarm around. Particles already inside the goal region will attempt to remain there.
  
  If the Minimum Goal Radius is set to zero, the Maximum Goal Radius designates the region the particles flock towards. They aim for any spot within this goal radius. Consequently, the smaller the Maximum Goal Radius, the more condensed the particles will be while they are flocking and swarming.
• Falloff Percentage: This value is a percentage of the Minimum and Maximum Goal spheres. For the Maximum Goal sphere, the Goal Radius Falloff value represents a distance outside the Maximum Goal Radius. For the Minimum Goal sphere, the Goal Radius Falloff value represents a distance inside the Minimum Goal Radius measured from its outer edge. These areas are shown in the following illustration.
  
  As long as the particles are within either of these two Goal Radius Falloff regions, the strength of the Flocking and Swarming effect will be determined according to the distance the particles are from the rims of the spheres. The Flocking and Swarming effect will be weaker as the particles approach the Maximum Radius Sphere. On the other hand, the Flocking and Swarming effect will be stronger as the particles travel further inside the Minimum Radius Sphere.
• Min/Max Cutoff Speed: The Min/Max values determine a range of speeds. Particle Storm will randomly pick a speed between these two ranges and apply that cutoff speed to a particle. It will do this for each particle. After a particle has reached this speed, Flocking and Swarming will treat the particle in such a way that its speed does not go beyond the cutoff speed.
• Max Divergence: Determines how much particles are allowed to "turn away" from each other. Higher angles will result in more chaos in each particle's direction. Lower values will create a more patterned effect where there is not a large variation in their heading angles. This is useful for fish schools and other behaviors that require the particles to move in tandem with each other.
  
  NOTE: The Divergence angle is limited between 0 and 180 degrees.
  



Flocking and Swarming radius illustration



• Position: This is the physical position of the Flocking and Swarming goal. Affected particles will flock to this goal from where they are emitted.
  
  Quick Tip! It is probably a good idea to keep the goals moving. Particles tend to bunch up when they reach a static goal. Keeping the goals moving will insure that the particles never actually reach them. Animate the position of the goals using envelopes, or parent the position to a LightWave object to move the goal around. Create multiple instances of Flocking and Swarming in different positions. Turn their effects on and off at various time intervals to get interesting flocking motions.
  
  
• Bounding Shape: The bounding area of effect for this controller. Particles outside the bounding shape will not be affected by Flocking and Swarming.