Only a few short weeks ago, the sim racing world was turned upside-down when Norweigan drifting personality and avid sim racer Fredrik Sorlie leaked a conversation between himself and Stefano Casillo of Kunos Simulazioni, in which the sim racer found himself on the receiving end of an aggressive virtual lashing from an otherwise respected developer within the sim racing community. While most of our readers rushed to take sides and either publicly blasted Stefano or accused Sorlie of being in over his head when it came to discussing tire behavior, lost in the community-wide argument was what the actual conversation centered around: tire behavior.
Casillo argued that the data and calculations powering the tire behavior in Assetto Corsa were the most important pieces of getting the virtual Ferrari on the screen to feel like a proper car driven to the edge of the tire, but Fredrik stated that his semi-random numbers inserted into the INI file – primarily the result of several trial and error experiments – produced a much more realistic range of vehicle dynamics on corner entry, which mirrored his own time spent blasting around the Nurburgring Nordschleife with his life on the line. Or, you know, something to that effect.
Today’s second Reader Submission comes from Richard Wilk, the in-house physics guru for rFactor’s Historic Sim Racing Organization – or HSO for short. The HSO website specializes primarily in full-length online races ahd championships held in machinery from an era of motorsports that placed speed over safety, either creating their own mods from the ground up, or re-building popular historic releases from the ground up to iron out their flaws. The website recently completed their highly competitive 1973 USAC championship to close out the 2016 calendar year, and are currently in the process of preparing for a 1980’s World Sports Car Championship event at Monza. Though these guys don’t receive much publicity on mainstream outlets, they’re busy as hell on their own little corner of the internet – consistently managing to acquire full grids for each and every event they hold.
According to Richard Wilks of HSO, you need more than just hard numbers – as Kunos Simulazioni have ruthlessly claimed when discussing tire behavior in private with real race car drivers – to create a convincing rendition of a virtual car, and it’s foolish to dismiss feedback from people who have driven the real thing, even if it goes against your own data. You’re building an experience, not a space shuttle.
Hello PRC! I’ve returned with another submission about the process of creating cars for all of your favorite simulators, but this time I’ve been a bit more outgoing than usual, and I’m finally comfortable revealing my name. You can read some of my past submissions HERE and HERE.
There was a lot of talk recently about Stefano Casillo from Kunos Simulazioni refusing to hear and even offending a guy with massive real life experience. To me, this is beyond unbelieveable. No, I don’t feel it’s appropriate to call names or question what Kunos are doing behind the scenes (though it may be a bit justified), but I’d like to explain to readers why this is all so preposterous to someone like me, who willingly spends his free time learning about cars, and creating a convincing set of physics for others to enjoy in a competitive setting.
As a physics modder, I can say that having a guy who not only drove the real thing, but understands how to be successful in a consumer simulator as well, and can flawlessly translate skills from one to the other, that’s pure gold. It’s already hard enough to find interviews or accounts from drivers detailing the real life experience because it’s not something auto racing journalists typically ask – they’re concerned about race strategies and other marketing things – so finding a guy willing to drive in a simulator for an excessive length of time and even show you the way that the car behaves by modifying the files himself… I have to say I’m a bit jealous of Kunos that they have fans willing to go through that lengths to help the developers.
So for Stefano to shoot these people down… It’s very dumb. Honestly, incredibly dumb. But this gets much worse. You see, even if he believes he has his tire model numbers absolutely correct, he’s putting too much faith into two really dangerous categories:
- That his physics engine properly translates those numbers into correct forces in all situations.
- That his tire model is already perfect, or realistic.
Looking at point number one, I guess Stefano’s pride must have been hurt to lash out at Fredrik like that, so it’s no small wonder he doesn’t even question that his physics engine functions perfectly in all situations. But point number two is something he should very well question, because nobody, and I repeat nobody, can claim to have tires nailed in sim racing. And this is where feedback is most important.
When I sit down and work on a car for HSO, and this entails everything from helping with a scratch made mod our guys created down to every last lug nut on the wheel, all the way to tweaking an existing mod that people like but doesn’t drive very well, tires are the absolute last thing I mess with. You can do everything else right or get it somewhere in the correct ballpark, but tires? Its not just the grip. It’s the load sensitivity, the slip angles, or the relationship between front and rear slip angles, and how that all translates through the flawed or incomplete tire models we have, into car movements. This is a massive grey area, and you can’t rely solely on numbers, especially because those numbers powering other parts of the physics engine – or data that has to be extrapolated from other pieces of data – are not 100% reliable in the first place. This is where accurate feedback is crucial. Too many times I see things other modders have gotten wrong, because people just assume things about these cars, and never read or were bothered to ask people with legitimate experience.
I can understand modders getting this wrong, because Porsche or Ferrari haven’t given them free reign of their private garage, nor do they have the budget to acquire sensitive data or take these cars out to a track for firsthand experience, but developers themselves? A team who are supposed to know the inner workings of their software? It’s really inexcusable.
How can quality mod teams for Assetto Corsa exist, if the people creating vanilla content behave like this? They should be setting an example, not being yet another “I never sat in this car in my life, but I know better” autistic manchild.
Even though we’ve sort of moved on from Stefano’s meltdown over Fredrik’s feedback and what it indicates about how Kunos Simulazioni operate, you raise an interesting concept that I’m sure the readers of PRC will appreciate (compared to a submission we posted earlier today, anyway).
When tires are still a bit of a black art that no single developer team – let alone real world car makers – have been able to master, why are Kunos behaving as if raw data and numbers they’ve set in stone are the answer to producing an authentic virtual recreation of performance driving? Consumer racing simulations – the ones we can buy off store shelves – are an approximation of vehicle dynamics using as much real world data that can be applied within the software, and then filling in the blanks with reasonable guesstimations. But physics engines themselves are an approximation of real life, using numbers to replicate the laws of the universe, so there’s no absolute guarantee the software powering these games is one hundred percent correct before we even place a car on the track.
Therefore, there’s no reason not to be open about feedback from avid sim racers with real world driving experience willingly plucking numbers into the game just to see what happens, because they might actually be onto something. And sure, let’s say after a ton of testing, their feedback results in experiments that are wholeheartedly inconclusive. That’s okay. It’s not a knock on you as a developer or as a person, it’s not them trying to undermine your years of obsessing over vehicle dynamics textbooks, it’s them saying “it doesn’t feel right to me, can we try going back to the drawing board so your software benefits me more on the real track than it already does?”
Unless there is something seriously wrong with your emotional state where even the slightest bit of feedback triggers immense hostility to anyone who crosses your path, this is how you improve the simulation value aspect of your simulator.