Publication details

Extreme-Density Crowd Simulation: Combining Agents with Smoothed Particle Hydrodynamics
Wouter van Toll, Cédric Braga, Barbara Solenthaler, Julien Pettré
In 13th ACM SIGGRAPH Conference on Motion, Interaction and Games, pp. 11:1-11:10, 2020.
Inria HAL page - Full paper (PDF)


In highly dense crowds of humans, collisions between people occur often. It is common to simulate such a crowd as one fluid-like entity (macroscopic), and not as a set of individuals (microscopic, agent-based). Agent-based simulations are preferred for lower densities because they preserve the properties of individual people. However, their collision handling is too simplistic for extreme-density crowds. Therefore, neither paradigm is ideal for all possible densities.

In this paper, we combine agent-based crowd simulation with the concept of Smoothed Particle Hydrodynamics (SPH), a particle-based method that is popular for fluid simulation. Our combination augments the usual agent-collision handling with fluid dynamics when the crowd density is sufficiently high. A novel component of our method is a dynamic rest density per agent, which intuitively controls the crowd density that an agent is willing to accept.

Experiments show that SPH improves agent-based simulation in several ways: better stability at high densities, more intuitive control over the crowd density, and easier replication of wave-propagation effects. Our implementation can simulate tens of thousands of agents in real-time. As such, this work successfully prepares the agent-based paradigm for crowd simulation at all densities.

BibTeX citation

    author = {van Toll, W. and Braga, C. and Solenthaler, B. and Pettr\'e, J.},
    title = {Extreme-Density Crowd Simulation: Combining Agents with Smoothed Particle Hydrodynamics},
    booktitle = {Proceedings of the 13th ACM SIGGRAPH Conference on Motion, Interaction and Games},
    year = {2020},
    pages = {11:1--11:10}