Flocks, herds and schools: A distributed behavioral model

TLDR

The collective motion of flocks, herds, and schools is a striking natural phenomenon, yet such complex motion is rarely reproduced in computer animation. This paper investigates a simulation-based approach to generate flock motion without scripting individual bird paths. The method models each bird as an independent particle that follows local perception, physics laws, and animator‑defined behaviors, producing collective motion through a distributed behavioral model. The resulting simulated flock exhibits emergent collective motion arising from the dense interaction of simple individual behaviors.

Abstract

The aggregate motion of a flock of birds, a herd of land animals, or a school of fish is a beautiful and familiar part of the natural world. But this type of complex motion is rarely seen in computer animation. This paper explores an approach based on simulation as an alternative to scripting the paths of each bird individually. The simulated flock is an elaboration of a particle systems, with the simulated birds being the particles. The aggregate motion of the simulated flock is created by a distributed behavioral model much like that at work in a natural flock; the birds choose their own course. Each simulated bird is implemented as an independent actor that navigates according to its local perception of the dynamic environment, the laws of simulated physics that rule its motion, and a set of behaviors programmed into it by the "animator." The aggregate motion of the simulated flock is the result of the dense interaction of the relatively simple behaviors of the individual simulated birds.