Humans react in a seemingly irrational manner during emergency evacuations; sometimes, people even get trampled in the process. But what if architects and developers could predict how large crowds might move through their buildings in the event of an emergency–and then tweak the designs to ensure that everything runs smoothly?

That’s the premise of MassMotion, a crowd simulator that allows users to view hundreds of thousands of simulated 3-D people moving through urban environments (i.e. train stations and airports), all by programming each individual with a distinct personality and agenda.

MassMotion isn’t the first crowd simulator, but it is the only one that can predict movements of unique 3-D individuals in a fully 3-D environment. It’s the most realistic crowd simulator out there–and it can run on any up-to-date computer.

Developed by Oasys Limited, the software has already been used by Arup in the design of projects like the Toronto Union Station, San Francisco Transbay Terminal, and Montreal Trudeau Airport. The software proved so successful that Oasys is now putting it on sale to the tune of $20,000.