IGN AU/IGN Readers: How much of the processing power is dedicated to the 360 frames a second physics processing?
John Wendl: Well, you have two primary restraints on any system like this. One is the CPU and one's the GPU. The GPU is used primarily for graphics, the CPU is used primarily for some graphics set-up, but it's also used for audio and physics in particular; physics and gameplay. So a good portion of the CPU bandwidth actually goes towards running the physics simulation, as well as the AI. And then the GPU is almost completely consumed with displaying the game at 60 frames a second visually. But we're doing things with physics that no other games are coming close to, with things like tyre flex. We model chassis flex. It's beyond just a rigid body physics system. We're doing things that race teams aren't actually even doing…
We work with Michelin and McLaren, and groups like that. McLaren really helped us with our aero modelling, because they've taken aero modelling to places that – y'know, how the air moves over the car and the turbulence it creates and what it does, so we partnered with them on that, and with Michelin on our tyre physics, so we're actually doing visual tyre deformation now. We do tyre temperature on the outside, middle and the other outside of the tyre. We do gas temperatures inside the tyre, which modify pressure, tread compounds, slip angle, all that stuff. We measure all that – it's calculating a tonne of things, to get the car to feel just right.
So that [way] a big old heavy classic Mustang with a twisty chassis and tall tyres will feel that way. Even though it's got a lot of horsepower, on paper it might look like it's a fast car, but once you get out on a race track, because of the limitations in the tyres, in the chassis flex, and how the suspension's set up, it's actually not that fast around a race track, compared to a new modern car. A lot of games you won't feel that difference because – honestly – they're not that different, and you have to simulate all these things to get that feeling, and whether you even know about it and can articulate that or not, you just know it feels right.
That, combined with sampling the physics at 360 hertz is critical because these cars can reach 200 miles an hour, and at 200 miles an hour at 60 hertz, you've covered almost ten feet, and there's a lot that can happen in ten feet that you're missing basically. At 360 hertz you're covering only about eight inches at that speed, so you just get a lot more fidelity and the car feels a lot more responsive.
looks good
