On the use of virtual animals with artificial fear in virtual environments

Virtual environments are often static and empty of life. One way of combating this problem is by populating the environment with autonomous agents that behave in a life-like manner. This paper discusses the incorporation of animals into such environments and the definition of appropriate behaviours that enrich the experience. Reynolds' flocking algorithm is extended to incorporate the effects of emotions, in this case fear. Deer are used as an example of flocking mammals and an autonomous agent architecture with an action selection mechanism incorporating the effects of emotion is linked to the extended flocking rules. Olfaction is used to transmit emotion between animals, through pheromones modelled as particles in a free expansion gas. Two experiments are reported that provide some insight into the impact of the various behaviours. The combination of reaction and naturalistic behaviours are concluded to be important in enhancing the virtual environment.