Modeling the spatial behavior of virtual agents in groups for non-verbal communication in virtual worlds

In this paper we propose a mathematical model for the concept of Personal Space (PS) and apply it to simulate the non-verbal communication between agents in virtual worlds. Persons within a group tend to maintain the distances between each other within a certain range that maximizes their degree of comfort. These distances reflect the type of their relationship, and changes in these distances reflect the evolution over time of their relationship. Human-like autonomous virtual agents should be also equipped with such capability to simulate natural interactions in virtual worlds. First we model the space around an agent as a probability distribution function which reflects at each point in the space the importance of that point to the agent. The agent updates dynamically this function according to (1) his relation and distance to other agents in the virtual space, (2) his face orientation, and (3) the evolution of the relationship over time as a stranger agent may become a friend. We demonstrate the concept on a multi-agent platform and show that space-aware agents exhibit better natural behavior.