SmartBody: behavior realization for embodied conversational agents

Researchers demand much from their embodied conversational agents (ECAs), requiring them to be both life-like, as well as responsive to events in an interactive setting. We find that a flexible combination of animation approaches may be needed to satisfy these needs. In this paper we present SmartBody, an open source modular framework for animating ECAs in real time, based on the notion of hierarchically connected animation controllers. Controllers in SmartBody can employ arbitrary animation algorithms such as keyframe interpolation, motion capture or procedural animation. Controllers can also schedule or combine other controllers. We discuss our architecture in detail, including how we incorporate traditional approaches, and develop the notion of a controller as a reactive module within a generic framework, for realizing modular animation control. To illustrate the versatility of the architecture, we also discuss a range of applications that have used SmartBody successfully.