KartSim: una simulazione realistica anche per i go kart
KartSim è una rigorosa simulazione di guida sviluppata da una sola persona, un programmatore di Melbourne di nome Zach Griffin. Si tratta di un progetto che, in qualche modo, segue il successo dell'italiano Assetto Corsa. Eccovi la nostra intervista con Zach, nella quale l'abile programmatore ci spiega in maniera molto chiara come funziona la fisica di KartSim.di Rosario Grasso pubblicato il 07 Maggio 2014 nel canale Videogames
Gamemag: Why did you choose the kart racing?
Zach Griffin: After going to the 96' Australian Grand Prix, I began playing racing games like Geoff Crammond's Grand Prix series and any Formula 1 game I could get my hands on. During secondary school, I began planning to make my own racing game with most of the features that are in KartSim today. I also began to race 100cc karts here in Melbourne in 2004 whilst I was studying Game Development. It was then quite obvious to combine my two interests and thus KartSim was born.
Gamemag: Is it true that you have created KartSim by yourself? How did you do?
Zach Griffin: It is. With the exception of the 3D driver model and the web services to control player account settings, I've created everything you see in the gameplay footage. It's certainly taken a lot longer than it would have if I had a full team, but it has given me the skills required to manage the project and interface with the different disciplines required to create KartSim, now there are more people involved.
Gamemag: What kind of work is there behind the physics of KartSim ? How did you create the different patterns of behavior of the various kart?
Zach Griffin: It's been a monumental task. Everything from the tyres to the drivetrain, chassis and steering kinematics has to be modeled accurately in order to reproduce the handling characteristics of a kart. This is why you see other attempts at simulating a kart never quite get the feeling right; you can't simulate a kart by tuning a sprung rigid chassis and hope to get an accurate result. As you can see from the slow motion footage in the Steam Greenlight trailer, KartSim's chassis is modelled using an FEM algorithm which simulates the flex of the chassis in real time. The end result is a chassis that is able to unload the inside rear wheel to allow a tighter cornering radius, just like a real kart.
Gamemag: Could you explain what you mean for Finite Element Method (FEM)?
Zach Griffin:In KartSim, the Finite Element Method allows us to model the deflection and compliance of the chassis due to external forces that are experienced when driving the kart. As a kart typically has so much caster (forward inclination of the kingpin), turning the steering wheel makes the inside front wheel push down (creating forces that push up on the chassis) and the outside front wheel lift up. FEM is then used to determine how much the chassis flexes (twist and bending moments) so the inside rear wheel can lift up off the ground.
Gamemag: What are the main challenges in the development of KartSim?
Zach Griffin: Outside of the physics, for sure the greatest challenge has been to architect the different components that make up the game. Today's games are enormously complex and unless you are a developer, it's quite difficult to appreciate the magnitude of whats going on under the hood. Add multiplayer support into the mix and the complexity rises dramatically, as you can no longer make any assumptions, with any degree of certainty as to what the players are doing. This is why I try to leverage as much existing technology as possible to reduce the amount of work required.
On top of that, consumer expectations are very high, there's a lot of competition, and whilst there is nothing wrong with that, you can't afford to release a game with any major flaws, bugs or broken features as you risk driving players away. Once they're gone, it's hard to get them back as you can see is the case with Battlefield 4. That's why you'll see development teams delay a release, as it is far more risky and damaging to release a broken product, than it is to delay the product or feature.
Gamemag: How will the multiplayer component? It will be possibile create private games and will be there support for dedicated servers?
Zach Griffin: We haven't confirmed how many players multiplayer supports yet, however I can confirm private servers are allowed and there is dedicated server support.
Gamemag: Have you used Unity to create graphics for KartSim. How have you adapted the development tools to create what you wanted?
Zach Griffin: The key is to choose the right tool for the job and try to do as little adaptation as possible. Unity was used only for the prototype as it allowed for rapid iteration of the game's design. The release version of KartSim is using a much more powerful and production ready engine, which allows us to concentrate on developing the game, rather than the underlying engine, as was the case with Unity. Also, speeding up the content creation pipeline is definitely where you can save a lot of development time and as such, I've written several custom editor plugins to allow the artists to create race circuits a lot faster than before.
Gamemag: Do you know of Assetto Corsa? Even that is a driving simulation independently developed by a small group of guys. What do you think about that game?
Zach Griffin: I've been a big fan of Stefano's work having played NetKar, NetKar Pro, Ferrari Virtual Academy and now Assetto Corsa. Kunos' Licensing Project Manager, Marco Massarutto, has also been very supportive during KartSim's recent Steam Greenlight campaign, so I have a lot of respect for the guys at Kunos Simulazione. As for Assetto Corsa, I've done more than a few laps in the game and love the feel of the cars. I can't wait until they add multiplayer support. As for improvements, I'd like to see the cockpit camera feel less floaty by increasing the interpolation time for the head movement and less time in between race restarts. That said, it's currently my favourite sim and I'd encourage everyone to buy it.
Gamemag: Your game will support Oculus Rift? Virtual reality could become essential for driving games like KartSim, because it makes driving more engaging. Do you agree?
Zach Griffin: KartSim supports the Oculus Rift. I don't think you could find many who could argue that VR doesn't make the experience a lot more immersive. I think the biggest problem VR faces is how to solve auxiliary problems like how players should interface with the game and their peripherals in a seamless way, and how to eliminate the motion sickness that many have experienced. Just like mobile development where development teams had to design the game around the controls, I'm sure development teams who support VR will have to learn and define the best practice. For driving games particularly, the key problem to solve is how to make it easy to push different buttons on the wheel and displays without being able see them. Maybe a hybrid VR system with a webcam attached may be the answer...
Gamemag: How have you funded KartSim?
Zach Griffin: I've self-funded the game to date by lecturing in Game Development at a local university here in Melbourne. I also used funds from my time working as a Project Manager and Business Analyst in the wagering industry.
Gamemag: You took five years to complete KartSim . Why do you feel that now is the right time to make it public?
Zach Griffin: I wrote the very first 2D prototype of KartSim back in 2005. A lot of the time I spent has been learning how to make the game, rather than making the game itself. Game Development has an incredibly steep learning curve; one that has taken many years to get to the top.
Aside from the game being ready to take public, I think gamers are also much more receptive to simulation driving/racing games than they have ever been. With the likes of Forza Motorsport and Gran Turismo continually pushing for realism, it has helped shine more light on the simulation genre and made it a little more mainstream. That said, I still think simulation games need to be more accessible and accommodating to new players; one area in which I think KartSim will excel at.
Gamemag: Which tracks and karts do you plan on featuring in the game?
Zach Griffin: The full track list hasn't been confirmed yet outside of the Australian tracks Oakleigh and the Go Kart Racing Club of Victoria (GKCV). The intial release will also feature an American and European circuit. As for the karts, KartSim will feature 100cc, KF1, KZ2, 125cc and junior classes.
Gamemag: Plan to implement driving aids or KartSim will be exclusively devoted to the fanatics of sports driving?
Zach Griffin: Absolutely. I think it's extremely important to allow people of all skill levels and experience to be able to enjoy the game. There's no reason that a game should cater to one group and not another. Of course there will be server options to restrict driving aids for the more advanced player, but everyone should be able to stay on the track if there's driving aids on.
Gamemag: When can we start playing KartSim?
Zach Griffin: The exact release date hasn't been confirmed, but we are targeting the middle of the year.