Gameplanet: What elements of Forza 3 were you least happy with that came up for revision in Forza 4?

John Wendl: Well, we were pretty happy with Forza 3 when it came out. I think some of the biggest innovation driven in Forza 4 didn't come out as a result of being disappointed with Forza 3, it was around Kinect, which we didn't know about back then. A lot of features in Auto Vista in particular that became born out of that. It was a huge innovation for us which was a shortcoming in Forza 3 that we didn't really realize at the time because the technology wasn't there.

Honestly, we were happy with the graphics at the time, but then we partnered with Hollywood for Forza 4 and really tried to de-construct how cinematic film and animation renders out CG, and came up with a lot of interesting new techniques, and now the visuals in this version of the game eclipse by far what we were doing in Forza 3. We continue to do screenshot comparisons with the two games and we can't believe how much better this game looks, especially considering it's on the same hardware.

So at the time of course we weren't disappointed with it, we thought it was great, but now when you look back it's pretty amazing what we're achieving graphically.

Gameplanet: What makes it so visually different this time around?

Wendl: We re-wrote our graphics engine from the ground up, both the technology and how we think about visuals. As I mentioned we partnered with Hollywood and hired a guy from Pixar, and really thought about how we put this stuff together. It started with leveraging a technique called "Image Based Lighting", which comes straight out of film, specifically it's an HDR idea – or High Dynamic Range based lighting. This is where you capture High Dynamic Range based images of the world, and that becomes your light source which casts light back into the scene, which means your environment is the light source for the car, and it makes the car really grounded in the environment and gives you this level of visual intensity and light intensity that's not possible with traditional lighting models.

For example, the sun on a TV screen is white, and a piece of paper is white – they both look white. But we all know the sun is infinitely brighter than a white piece of paper, and what this effect allows us to do is similar to High Dynamic Range photography. When we capture this we know the sun is infinitely brighter, and when it lights the car and reflects in the car, it shows up infinitely brighter than a white cloud in the sky, for example, that doesn't emit light, it only reflects light.

It does two things for us, it makes the car look really grounded in the environment, and it gives a range and intensity to the light that just wasn't possible before. The end result is a cinematic, CG-quality render at the end of the day. Then of course, for Auto Vista, we created a whole new level of assets. Those cars are approaching a million polygons, and the level of detail in there and the surface properties we've developed – true weave carbon fibre, leather, stitching, seatbelts, colour-shifting paint, the stainless-steel on the De Lorean, things like that. Our material and shader research has been incredibly developed since Forza 3. So all of those together have added up to what is a pretty amazing visual accomplishment compared to Forza 3, and honestly to anything else out there in my opinion.

Gameplanet: It's interesting you mention that, because there's been a lot of chatter in the industry about a next generation of consoles. Was this technology developed with future hardware in mind?

Wendl: There always has to be whatever is next down the road, but honestly we don't really think about that a whole lot with Forza 4, because we knew we were shipping on the Xbox 360. We were just thinking about how we could bring the highest quality graphics, fidelity and realism to our customers at any given time, and Hollywood has traditionally been ahead of games in their level of sophistication. In some cases they can take hours, if not days to render a single frame of a film, we have to render ours 60 times a second, so a lot of the effects they do are much more sophisticated. But we've been able to go in and learn from those, and reverse engineer them to figure out how to pull them off in real-time on the console.

We start with visual targets and we're trying to achieve a certain visual look, so we need to make sure the hardware is a delivery mechanism for the look we're trying to deliver. So honestly, we're going for a certain look, and immersion and realism regardless of the hardware that we're going to be on. Of course, more powerful hardware gives us more opportunities to push and do things more, but this is our third time being on the Xbox 360, and each time I would argue that the graphics have made an improvement that is equal to what you would expect to see in a hardware change, it made that big of a jump. So it's amazing to me what this team is able to do every time we ship a new version of this game on the same hardware. We just get smarter and better at what we do, and just thinking about the visual quality of Auto Vista now; at the launch of the 360 it would be unthinkable, you couldn't have imagined we could have gotten there on this hardware, so it's pretty amazing.

Gameplanet: Is the Kinect functionality in the game a viable method of control for the more hard-core gamer?

Wendl: I think it is. When we first saw the sensor, we saw it as a real opportunity in two ways. One, we've always tried to reach out – we believe that people come at car passion and car culture from a lot of different angles, and not all of them are hard-core gamers and grew up with a controller in their hand. My Dad is one of them, he wants to play the game that his son worked on, but he doesn't really play videogames. He loves cars, we used to go to car shows when I was younger, but the controller is a real barrier for him, and that's why we've been trying to introduce assist, things like the driving line, auto-breaking, and now auto-steering to try to make the game more approachable, whether it's an eight-year-old kid, or a 60-year-old Dad, and Kinect was a natural extension of that as a way to bring people together around their passion for cars without the controller being a barrier. It's allowed us to do that in a natural way. But we also wanted to make it relevant for hard-core gamers, we know that hard-core gamers are never going to play Kinect driving with their hands up in the air, that's really more for Dad and his son that want to just play on the couch and have fun together.

But we believed there was power in that sensor that was relevant to hard-core players as well, and it's manifested itself in a couple of different ways in the game. First is with head tracking. Even if players are playing with a controller or a wheel, instead of using traditionally what games have done with a thumbstick, or something like that, to try to move your head around to look for the apex of the corner, we know that drivers – when they drive naturally – look to where they
want to go. To the apex of the corner to track out when they're driving. In the game, that's pretty challenging to do by manipulating triggers and thumbsticks, or the wheel and the pedals. So we were able to let them play how they wanted to play, but track their head using the Kinect sensor. We found that players actually naturally look into the corners when they're playing anyway, even before they had the Kinect sensor, so we're just tracking that now and naturally moving the camera when they're in cockpit view to look through the corner, look to the apex to track their heads.

It works very naturally and intuitively, so I think it's a way for hard-core players to get some value out of Kinect, and make their driving experience better.

The other way we've done it is with UI hyperlinking using voice. A game like Forza has a very deep UI, many levels deep. You might be five layers deep in the paint editor, for example, and you can just say "Xbox community" or "Xbox career", and it'll back you out and save your work, and throw you back into... that's funny, I'm sitting in front of my computer and I just said it, and a little voice menu came up in the game (laughs) but it's kind of a power user for hard-core gamers. If you don't know it's there, it's not the end of the world, but for guys who spend a lot of time in the UI, painting or customising cars and going deep into the community menu, it's a way to kind of jump around this massive UI in a quick and efficient way, which is pretty cool too. And I think we're only starting to scratch the surface in the ways this sensor is going to be relevant to hard-core players.

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