Abstract
Heterogeneity in virtual crowds is crucial for many applications, including visual effects, games, and security simulations. Nevertheless, tweaking the behavior parameters of a character to achieve crowd heterogeneity is frequently hard. In particular, it is typically unclear how tuning some non-intuitive parameters at the agent level will eventually affect both the microscopic or macroscopic scale of the crowd. This paper proposes an activity-centric framework for authoring functional, heterogeneous virtual crowds in semantically meaningful environments. The specification of locations as environmental attractors and agent desires are used to compute "influence maps", which allow the emergence of heterogeneous behaviors in a large virtual crowd in a complex scene. The same framework can also facilitate the authoring of complex group behaviors, such as following behaviors or families, by treating moving agents as attractors. Accompanying results demonstrate the framework's potential by authoring crowds in different environments. The experiments highlight the ability to easily orchestrate purposeful, heterogeneous crowd activities both at a macroscopic and microscopic level with minimal parameter tuning.