At this point in time (June 2015), there is a lot of skepticism about VR in the game industry. Typical things game developers say about it include:
- The Virtual Boy already showed us that VR doesn’t work.
- They tried VR in the nineties -- it didn’t work then, why would it work now?
- It’ll just be a fad -- like the Kinect, or 3DTV.
- Nobody is going to want to put a device on their face.
- The motion sickness problem is unsolvable.
- What’s the point? There’s nothing you can do in VR you can’t already do on a game console.
My point of view is a bit different. I believe that after a massive flurry of VR hype in 2016, VR devices will be on the market indefinitely. They will not completely replace our existing game platforms, but instead they will join our gaming ecosystem, living and thriving alongside PC, console, and mobile gaming. The difference will be that VR gaming will be the most intense gaming experience, the mode of gaming that hardcore players will value most in the long run. I have been developing VR games for over twenty years, and in this article I’ll give tips for creating the best VR experiences possible, many of which were learned during the making of the initial prototype of one of Schell Games’ new VR titles: I Expect You To Die.
I Expect You To Die
I Expect You To Die is an escape-the-room VR puzzle game with a super-spy theme. So far, we have created a rough prototype puzzle (The Library) and a detailed vertical slice puzzle (The Car in the Plane). Our current version is designed for the Oculus Rift, and assumes the player is seated at a desk, using the mouse to interact with the world. We have put both of these levels up on Oculus Share, with the plan of making a complete game for sale once the Oculus Rift is launched. We may also want to release it on other platforms, but we aren’t sure yet, for reasons I’ll discuss later on.
Aladdin’s Magic Carpet VR Adventure, installed at DisneyQuest in 1998, is still operating today.
My VR History
Am I biased in favor of VR? Undoubtedly. I started working on it in earnest in 1992, and have been helping to develop VR games somewhat continuously since that time. It began with my graduate work at Carnegie Mellon University, which led to me joining the Disney VR Studio in 1995 where I helped develop Aladdin’s Magic Carpet VR Adventure and other VR experiences for DisneyQuest. In 2002, I returned to Carnegie Mellon where I have been teaching the Building Virtual Worlds class at the Entertainment Technology Center for the last 13 years. During that time I have helped students create over 500 VR worlds. In parallel to my teaching, I run Schell Games, a large (100 developer) game studio in Pittsburgh. I think you can imagine now that affordable high-end VR devices will at last be available in the home, it is hard for me to resist making games for them!
Daniël Ernst’s “Blocked In” gave Schell Games a lot of inspiration.
When Oculus made its initial announcements about launching a consumer VR platform, I was quite eager to get a Schell Games team started working on it! Unfortunately, it wasn’t as easy to get started as I had hoped. Far from jumping on the VR bandwagon, many of my team members raised an eyebrow at my VR enthusiasm, stating all the objections I listed above, and more. I tried to urge them on, insisting that the new OLED displays and optical tracking systems allow for far more powerful experiences than in the past, but still, most were not convinced. Showing is always better than telling, so what ultimately started to bring people around was an opportunity to experience some of the best demos that were out there. None of them were great, but they were good enough to inspire some of our team that maybe something was there, and there were several who, trying the demos circa July 2014, felt “we can certainly do better than this.” That year, for Jam Week (a yearly Schell Games ritual where all normal work stops so everyone can spend a week working on a passion project), Senior Engineer Jason Pratt pulled together the best of the best VR demos that he could find, and started on some experiments of his own. He developed a method of mouse interaction that we all felt was interesting and unique, and might work well for the Oculus Rift. At the same time, going through the set of demos Jason had downloaded, I couldn’t help but be impressed by Blocked In, an Oculus Rift demo that gave me a stronger sense of presence than I had ever felt in a VR world, even though, as a player, I could take no action but to look around. All of this generated a lot of discussion among our team.
Hexius: An early Schell Games prototype that had some problems.
Soon, another SG engineer (Matt DeLucas) started riffing on Jason’s work, creating Hexius, a world that used Jason’s unique VR mouse interface to choose where to teleport next. Not satisfied with mere teleportation, Matt turned it into flying, which promptly made us all motion sick. This led some to conclude that the medium was worthless. After all, what good is a videogame where you can’t move without throwing up? I countered that not all videogames require movement -- many successful games are about sitting still, and defending territory, or solving puzzles. The response to that was that when players put on a VR headset, they want to feel powerful, like a superhero. How could it ever be interesting to be a superhero who was tied up and couldn’t move? But… wait! That happens all the time! Superheroes, from Batman to Wonder Woman to James Bond are always getting tied up by villains, and having to escape through clever puzzle solving! We all became fascinated by this idea, and moments later, inspired by the famous phrase from Goldfinger, came up with the working title I Expect You To Die. We then pulled a team together, led by Mike Traficante, former director of Enemy Mind.
As we developed I Expect You To Die to its current state, we learned a number of lessons that I am pleased to share here.
Like VR, psilocybe semilanceata mushrooms can provide both visions and nausea.
Lesson One: Motion Sickness Can Be Eliminated
When you think about it, the phenomenon of motion sickness is incredibly strange. A person is confronted with unusual motion (say, that of a boat, car, or roller coaster), or the appearance of motion (say, an IMAX movie, or VR), and their body responds by becoming gradually more nauseous, and possibly, ultimately vomiting. Why vomiting? Why not sneezing, or getting chills, or feeling tingly, or any other number of possible physiological responses? Why any response at all? The answer is known as the “toxicology hypothesis”. Certain poisons (from some mushrooms, for example) can disrupt the neurology of the brain such that the input from the little hairs in our inner ear (which detect acceleration and rotation) do not align with the input from our visual system. These poisons must have been a significant problem sometime in our evolutionary past, because wise old nature has programmed our brains to vomit when this happens, thus saving our lives. The problem is that poisons are not the only way to cause this disconnect -- reading in the car, riding the Tilt-a-Whirl, and engaging in certain VR experiences can do the same thing.
Can we disrupt this mechanism somehow? Certain drugs (Dramamine, for example) do just that, but as Spalding Gray once noted about using drugs to disable certain parts of the brain, “there is no such thing as precision bombing,” and these drugs tend to make players feel drowsy and disconnected. One day (around 2060 or so, by my guess), we’ll probably have some kind of nanotechnology that can safely calm our motion sickness circuit without side effects, but until then, we have to live with it. Exactly what triggers motion sickness differs vastly from person to person, but our team has been struck by the fact that despite testing with many different people, we are seeing virtually no motion sickness on I Expect You To Die. Here are our tips for creating VR with no “motion discomfort”:
Keep the framerate up. Consider 60 fps your new absolute acceptable minimum. 90fps or more should be your goal. Yes, I know this is hard. Yes, I know that PC platforms are variable. I don’t care. Your head and eyes can move quite fast, and when you are much below these high frame rates, your brain starts to sense something is wrong. Some people disagree, insisting that the brain can’t even detect the differences between such high frame rates -- that film has established that 24fps is plenty. If you feel this way, try this experiment. Go out under a fluorescent streetlight one night, and toss a ball in the air. The streetlight is pulsing at 50-60 times a second. If you just look at the light, it seems to be continuously on. But if you look at the ball, you can clearly see the individual light pulses. But you don’t even have to go outside. Pick up your PC mouse and shake it back and forth, and watch your cursor. Your screen is likely updating at 60 fps -- and you can clearly see the discrete positions. The way the brain perceives motion is not simple or easy. In the new world of VR, frame rates below 60 fps are no longer feasible.
Avoid virtual camera movement. I know. You want to make a first person shooter, you want to make a racing game, you want to have a dogfight in space. All of these seem to require a virtual camera that whizzes all over the place while the real camera (the player’s eye) stays still. Well, guess what? Any time you create a disconnect between the eye and those little hairs in the inner ear, your player will become nauseated. So, yes, that means a lot of kinds of gameplay are off the table. Keep in mind, though, that for everything that VR takes away, it gives something new that couldn’t be done before. Being able to move your head and body through an environment, even for a short distance, is an incredible experience, as is manipulating virtual objects with your real hands. It requires some creativity to design within the bounds of the VR box, but if you are willing to do it, you can create powerful experiences that have just about zero motion sickness.
If you must move the camera, don’t accelerate. Funny thing about those little hairs in your ears -- they can only detect acceleration, not velocity. They can’t tell the difference between zipping down the highway at 80 miles per hour, and sitting perfectly still. What they notice is speeding up and slowing down. When I coded up the locomotion system for Aladdin’s Magic Carpet VR Adventure at DisneyQuest, I took advantage of this fact by making the motion of the carpet be as linear as possible. Some amount of acceleration was necessary, though, and as a result, some motion sickness was inevitable. It was very limited, however, because the experience is on a five-minute timer, and most people can endure five minutes of mild virtual motion without much discomfort. For home play, however, five minutes is generally not an acceptable duration. Our initial I Expect You To Die prototype, for example, generally engages first-time players for twenty to thirty minutes or longer. Accordingly, the only virtual motion we have involves driving your car out of the plane, which only happens at the culmination of the experience, and is linear motion lasting only a few seconds.
And whatever you do, keep the horizon level. Certain kinds of motion, virtual or real, are shortcuts to trigger your motion sickness alarm circuit. Rolling the camera in a “barrel roll” style, so that the horizon does cartwheels in front of the player’s eyes is the quickest shortcut to puketown. So -- don’t do that. The canals in your inner ear that control all this are circular, and very good at detecting rotation, so generally, you should avoid virtual rotation of any kind. Part of what makes VR unique is that it lets players really turn around -- for real! Use real rotation to let players look around an environment, and avoid virtual rotation whenever possible.