Interesting interview with Michael Gourlay (Senior Software Engineer at Electronic Arts) about the state of fluid simulation in games today.
1. What is the state of fluid simulation in games today?
— Most games do not perform fluid simulation. Usually they use particle systems where the particles do not interact with each other.
The only game I have worked on that uses anything like a real fluid simulation are NASCAR 2009 (which is no longer made) and MMA (which has yet to be released) — and both of those use my visual effect system.
— The most popular form in games is Smoothed Particle Hydrodynamics (SPH) which works well for gloppy liquids and it works well for filling containers with sloshing, viscous goo, but it lacks the ethereal delicate motion of fine wisps of smoke or the broad-scale turbulent motion that comes from vorticity (and specifically, from vortex stretching).
3. There are different types of simulations. What are the challenges faced in simulating fluids?
— The biggest challenges to overcome are speed, stability and enduring fine-scale motion. Usually you can pick any two: You can have fast, stable viscous motion, or slow stable fine motion. (Unstable simulations simply explode into nonsense.) So the challenge then is a question of how to obtain all three.
— One possible solution is to throw huge amounts of compute power at the simulation — such as the GPGPU solutions which have been
popular in the past few years. But for games, that simply does not work — games already use the entire GPU for rendering.
No GPU horsepower remains for simulation. But multi-core CPU’s are well-suited to the problem.
I totally agree with the last sentence: multi-core CPUs are well-suited for fluid simulations and you’ll be able to test this affirmation with the new FluidMark 😉