breve is a simulation environment which allows users to define the behaviors and interactions of different types of agents in a simulated 3D world and observe the emergent behaviors. breve is conceptually similar to packages such as Swarm and StarLogo, but simulates objects in a continuous 3D world with continuous time. breve thus allows simulation involving realistic collision detection and physics.

Agent behaviors are written in a simple object oriented language called "steve". Users define an agent's behavior by specifying how the agent interacts with the world at each timestep and how the agent interacts when it collides with other agents. breve includes full collision detection and experimental support for real physical simulation of rigid bodies.