Social Forces Model with Human participants on the BBC

The BBC's science series 'Bang goes the Theory' recently had an episode on crowd behaviour. It shows a fascinating way of getting plenty of research out there into the public eye, using very short clips of research taking place based on certain themes. Anders Johansson, who still works with CASA, ran an experiment based on the 'social forces' model.

To give a heads up, the social forces model is an agent based model that simulates the microscopic movements of pedestrians. The motion of these pedestrians are described by subjecting them to 'social forces'. These forces are exerted by the pedestrians personal environment, as well as the interactions with other pedestrians in this context.

The movement of these pedestrians governed by these social forces are defined by the equation below:



If you'd like more details on the paper, it can be found here

An example of a social forces simulation model can be seen running in this video below:




Now, with this BBC episode, you can check out this model in a real world example with the help of an experiment with human participants, where you can see the effect of jams during an evacuation in a potential real world situation, and how a very simple solution of placing an obstacle at the exit can actually improve the flow of people through a door when evacuating a building. Although, your intuition I'm sure would say that it would not make sense. Actually, as this obstacle separates the flow of people, it prevents a jam occuring at the door, and therefore, creates a smoother flow through the door. Have a look, it's available for another 10days, and the experiment runs from around the 24 min mark, UK users only I'm afraid:

BBC Bang goes the Theory S6 Ep 4

Enjoy!

GPU Crowd Simulation

This is a conference sketch by Shopf, J., Oat, C., Barczak, J., presented in Siggraph Asia 2008.

I've been talking about how I am looking into creating a crowd simulation on the GPU. The sketch states that, to their knowledge it is the first implementation of a massive crowd simulation entirely on the GPU. A video clip of the simulation can be seen by clicking the picture below, and the slides of their Siggraph Asia 2008 presentation can be found here.



The implementation consists of a simulation of 65,000 agents at realtime frame rates. They have used a framework that combines a continuum-based global path planner (similar to the continnuum crowds post I did earlier), with a local avoidance model at a finer scale.

This also allows the level of detail to change as the view is scaled. There are other conference sketches by ATI, such as 'GPU Tesselation for Detailed, Animated Crowds', and 'GPU-Based Scene Management for Rendering Large Crowds' that must have been used in the simulation.

These sketches give an interesting insight into the capabilities of the GPU for simulating massive crowds, and how the level of detail can be varied based on the scale.

Continuum Crowds

This is a paper by Treuille, A. Cooper, S., and Popović, Z, presented in Siggraph 2006.
It's a real time crowd model based on continuum dynamics. The motion of crowds is controlled by a dynamic potential field, which allows it to avoid moving obstacles without the need of explicit collision avoidance. Their paper and video can be downloaded here.



This paper presents a lot of potential in creating a real time crowd simulation with large crowds. It would be interesting to see other implementations of this technique.