Endorphin

Endorphin is a dynamic motion synthesis software package developed by NaturalMotion. Endorphin can be used to generate computer simulations of large numbers of independent characters interacting with each other and the world according to brief scripts or 'behaviours'. It combines physics, AI, and genetic algorithms to create realistic animations. Unlike Euphoria, also developed by NaturalMotion, Endorphin is not an engine, but a 3D animation tool for Windows PC.At the heart of the software is an adaptive behaviors module which assigns context-sensitive motions to characters based on their surroundings --- for example, football players could be programmed to automatically tackle when near another player, or a swordsman could swing to attack nearby enemies. This automatic behaviour generation differentiates the software from competitors, and reduces the burden on animators to individually select behaviours for each agent in a large scene.

Endorphin is free.Download from http://www.naturalmotion.com/downloads.htm and sign up to use this fun software.