Flocking algorithm in povray, v. 7

Here's a project that I dusted off: flocking algorithms, programmed in povray's SDL.

Here are the key components:

• A maximum value for the acceleration.
  
• A drag force where a component of acceleration is -0.3*log(speed)
• A mission or target position, with an acceleration component pointed in the direction of the target.
• A crowd or collision avoidance component of acceleration, where each particle experiences a repulsive force equal to the sum of: the vector from each other particle, divided by the distance of each pairing squared.