Turn 10 on why Forza Motorsport 5′s physics are ‘impossible on last-generation hardwa

http://media.edge-online.com/wp-cont...torsport-5.jpgTurn 10 Studio’s creative director Dan Greenawalt will talk about the brutal, complicated maths that underlie Forza’s handling model for days, if that’s what it takes to prove the necessity of next-generation hardware for making Forza Motorsport 5 work. “The things we’re doing in physics now are simply impossible on last-generation hardware,” he says. “The amount of power to do the calculations we’re doing was just not available, and we didn’t have the knowhow as an industry to do some of the things we’re now doing.”Greenawalt offers an example: “We did good suspension in Forza 4, but there was more to be done. We’re adding open-wheel [cars] in Forza 5, like the 1976 Ferrari and McLaren from the movie Rush, so we wanted to reinvestigate what it takes to do a race suspension model, and that benefits all our cars. Now we have more accurate movement as we’re doing a reverse-kinematic model. Basically we’ve measured all movement – the length of the swingarm, the length of the A-arm – we have all that modelled.”“Tyres,” Greenawalt says, with a full stop. Forza 4 simulated tyre flex using variables ported directly into the game from Pirelli’s own test data, but Greenawalt wanted more.“I was asking Pirelli, ‘These tyre curves you have, this data… how are you isolating camber from wear from pressure and so on?’” he says. “Pirelli’s take was, ‘We don’t and [you can’t]’. So we found a new partner for Forza 5: Calspan. Calspan is not a name that anybody knows, unless you’re an engineer. The testing that Pirelli was doing on their tyres is called Calspan testing; that’s what all the tyre manufacturers use. [Calspan’s] take was different to Pirelli. It said, ‘We’ll need palettes of tyres,’ so we bought palettes of tyres and sent them to Calspan and [it] did two weeks of testing – morning, noon and night – isolating these variables. We now know things about Pirelli tyres that Pirelli doesn’t know about Pirelli tyres. We know things about Toyo and Yokohama that are going to help write the textbooks in two or three years.”

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