Constraint-based model for synthesis of multimodal sequential expressions of emotions

Emotional expressions play a very important role in the interaction between virtual agents and human users. In this paper, we present a new constraint-based approach to the generation of multimodal emotional displays. The displays generated with our method are not limited to the face, but are composed of different signals partially ordered in time and belonging to different modalities. We also describe the evaluation of the main features of our approach. We examine the role of multimodality, sequentiality, and constraints in the perception of synthesized emotional states. The results of our evaluation show that applying our algorithm improves the communication of a large spectrum of emotional states, while the believability of the agent animations increases with the use of constraints over the multimodal signals.