Behavior authoring is a technique that is widely used in crowd simulations and in simulations and computer games that involve multiple autonomous or non-player characters (NPCs). There has been growing academic and industry interest in the behavioral animation of autonomous actors in virtual worlds. However, it remains a considerable challenge to author complicated interactions between multiple actors in a way that balances automation and control flexibility.[1][unreliable source?]
Several varieties of behavior authoring systems have been created.