Ulicny, BranislavThalmann, Daniel2015-02-162015-02-1620021467-8659https://doi.org/10.1111/1467-8659.00634While virtual crowds are becoming common in non-real-time applications, the real-time domain is still relativelyunexplored. In this paper we discuss the challenges involved in creating such simulations, especially the needto efficiently manage variety. We introduce the concept of levels of variety. Then we present our work oncrowd behaviour simulation aimed at interactive real-time applications such as computer games or virtualenvironments. We define a modular behavioural architecture of a multi-agent system allowing autonomous andscripted behaviour of agents supporting variety. Finally we show applications of our system in a virtual realitytraining system and a virtual heritage reconstruction.ACM CSS: I.3.7 Three-Dimensional Graphics and Realism-Animation, I.2.11 Distributed ArtificialIntelligence-Multi-agent systems10.1111/1467-8659.00634767-775