I describe work in progress on a system for interactiveprototyping of AI-based characters. A sort of "Sims construction set," the system combines a simple physics simulation with a set of domain-specific languages to allow programmers to quickly build and test character AI. It allows iterative, incremental development in which behaviors can be compactly authored, tested, monitored, and hot-swapped for new behaviors, using in-game editing and debugging facilities.

This paper describes a system that greatly simplifies the task of authoring new behaviors for virtual characters, including physical interactions between characters and other characters or objects. The system in implemented within Twig and allows users to interactively generate and test procedural controllers for characters, as well as triggering mechanisms and arbitration mechanisms for behaviors. It allows users to quickly add new behaviors, or reparameterize existing behaviors, without access to a motion capture studio or professional animators, making it a natural choice for AI researchers, particularly those operating within a university environment. Moreover, it allows a level of continuous parameterization that would be difficult to achieve with traditional animation techniques based on state machines and blending.