### Summary

This was the first influential paper on flock simulation. The author introduces a distributed behavior model for simulating a flock. In this model, each member of the flock acts independently. At each step in the simulation, the individual members make decisions on which direction and how fast they should move.

### Problem

Realistically simulate the natural flocking behavior exhibited by animals such as birds and fish.

### Methods and key ideas

This paper lists three behaviors that lead to flocking: (1) collision avoidance, (2) velocity matching, and (3) flock centering. One problem addressed in the paper is conflict between these behaviors. For example, the collision avoidance behavior may produce an acceleration in one direction while flock centering produces a different direction. The resulting motion may cause a collision. Their solution is to, essentially, prioritize the behaviors such that one behavior may take precedence over another.

Finally, they deal with the issue of avoiding environmental obstacles. The solution they chose is is called steer-to-avoid. In this method, members of the flock consider obstacles in their local field of view. It then computes a new acceleration in order to route the member just to the side of the obstacle.