Virtual humans: lessons learned in integrating a large-scale AI project

Virtual humans are computer generated characters that can populate games or simulations. The behaviors of virtual humans are not scripted, but instead they use sophisticated AI techniques to reason about their environment and events as they unfold. Based on that reasoning, the virtual humans respond in believable ways. Virtual humans can interact in natural language, understanding speech and responding with synthesized speech. In addition to verbal communication, virtual humans can use non-verbal communication means such as gestures. In addition to rational behavior, virtual humans also have the ability to model and mimic human emotions.At the USC Institute for Creative Technologies, we have been engaged in the construction of virtual humans for the past six years. This project is not only a significant AI research effort, but it is also a significant software engineering task because a number of research projects must be integrated and work together to realize the virtual human. In this talk I will outline the virtual human effort, describe some of the synergies that have emerged from the software integration effort, and report on the lessons we have learned in this large-scale integration effort.