Authoring Virtual Crowds: A Survey

Abstract

Recent advancements in crowd simulation unravel a wide range of functionalities for virtual agents, delivering highly-realistic, natural virtual crowds. Such systems are of particular importance to a variety of applications in fields such as: entertainment (e.g., movies, computer games); architectural and urban planning; and simulations for sports and training. However, providing their capabilities to untrained users necessitates the development of authoring frameworks. Authoring virtual crowds is a complex and multi-level task, varying from assuming control and assisting users to realise their creative intents, to delivering intuitive and easy to use interfaces, facilitating such control. In this paper, we present a categorisation of the authorable crowd simulation components, ranging from high-level behaviours and path-planning to local movements, as well as animation and visualisation. We provide a review of the most relevant methods in each area, emphasising the amount and nature of influence that the users have over the final result. Moreover, we discuss the currently available authoring tools (e.g., graphical user interfaces, drag-and-drop), identifying the trends of early and recent work. Finally, we suggest promising directions for future research that mainly stem from the rise of learning-based methods, and the need for a unified authoring framework.

Investigating effects of future path visualisation on path choices during collision encounters

“…Motion representation using sketches has been used to fine-tune simulation models that accurately represent pedestrian walking behaviours (Colas et al, 2022, Mathew et al, 2022. Also in other crowd simulation works that used drawings (Lemonari et al, 2022), sketches would depict how a person moved in a scene; defining his global path, the motion trajectory and also defining the motion paths of all other agents in the scene. Sketch based motion path approximation has also found its use in the sports domain.…”

P2C: A Paths-to-Crowds Framework to Parameterize Behaviors

“…Therefore tools for authoring virtual crowds are crucial components in most simulation frameworks. Crowd simulation is a complex field making authoring a broad and multi-level task, as the user can interfere in several stages of the generation [29]. Authors can have influence over one or more crowd simulation components such as high-level behaviors, path-planning, local movements, animation, visualization, and post-processing.…”

Development of a Realistic Crowd Simulation Environment for Fine-Grained Validation of People Tracking Methods

“…AGORASET [17] is also a visual synthetic dataset for crowd video analysis. For a comprehensive overview of databases and simulators, see the following review articles [18,19,20,21]. In [22] the analysis of the statistical properties of real word datasets is available.…”