Flying Free Comments on Craig W. Reynolds’ Flocks, Herds, and Schools: A Distributed Behavioral Model Cailin K. Andruss Virginia Commonwealth University NSF BBSI Program

Example

Example 100

Example 100

Example 100

Example 100

Example 100

Example

Example

Can a flock of birds be modeled without individually programming each bird’s path?

Natural Flocking Millions of herring can travel in schools spanning 17 miles just as easily as a dozen birds can form a flock for a brief flight.Millions of herring can travel in schools spanning 17 miles just as easily as a dozen birds can form a flock for a brief flight. If flocking ability is independent of flock size, how do the flocks coordinate?If flocking ability is independent of flock size, how do the flocks coordinate?

The Secret: The Neighborhood Based on a Diagram by Craig Reynolds

Acceleration Requests Collision Avoidance: Stay clearCollision Avoidance: Stay clear

Acceleration Requests Velocity Matching: Stay on trackVelocity Matching: Stay on track Collision Avoidance: Stay clearCollision Avoidance: Stay clear

Acceleration Requests Velocity Matching: Stay on trackVelocity Matching: Stay on track Flock Centering: Stay closeFlock Centering: Stay close Collision Avoidance: Stay clearCollision Avoidance: Stay clear Diagrams by Craig Reynolds

The Brick Wall

Prioritize the acceleration requests.Prioritize the acceleration requests. Set a maximum acceleration.Set a maximum acceleration. Allow acceleration up to the maximum with the highest priority request getting first dibs.Allow acceleration up to the maximum with the highest priority request getting first dibs.

The Brick Wall Prioritize the acceleration requests.Prioritize the acceleration requests. Set a maximum acceleration.Set a maximum acceleration. Allow acceleration up to the maximum with the highest priority request getting first dibs.Allow acceleration up to the maximum with the highest priority request getting first dibs.

The Brick Wall Prioritize the acceleration requests.Prioritize the acceleration requests. Set a maximum acceleration.Set a maximum acceleration. Allow acceleration up to the maximum with the highest priority request getting first dibs.Allow acceleration up to the maximum with the highest priority request getting first dibs.

The Result (click here for movie) (click here for movie)

Take Home Message The secret: Limit vision of boid to neighborhoodThe secret: Limit vision of boid to neighborhood Boids follow three rules: 1. Collision avoidance 2. Velocity matching 3. Flock centeringBoids follow three rules: 1. Collision avoidance 2. Velocity matching 3. Flock centering More urgent rules receive priorityMore urgent rules receive priority

Application to VPP The Virtual Parasite Project uses swarming to model parasite activity.The Virtual Parasite Project uses swarming to model parasite activity. The accuracy of theories about their activity can be tested.The accuracy of theories about their activity can be tested. Experiments can be performed more quickly in silico than in vitro.Experiments can be performed more quickly in silico than in vitro.

References Reynolds, C. W. (1987) Flocks, Herds, and Schools: A Distributed Behavioral Model, in Computer Graphics, 21(4) (SIGGRAPH '87 Conference Proceedings) p Acceleration Request diagrams from Craig Reynold’s Boid’s Page: Thanks to Jeff Elhai for help with dewordification