VR Sickness; It’s a real thing

Posted: 02.19.15

After fading away in terms of consumer popularity in the late 1990s, with advent of low cost sensors and optics, and the unmitigated enthusiasm of Palmer Luckey Virtual Reality (VR) has roared back to life with a vengeance. But, it still has the same issue as it did in the 90s—graininess and motion or VR or Sim-sickness.

Using the Oculus Riff DK2 as an example, the resolution is 1920 x 1080, split between two eyes, or 970 x 1080 per eye. The refresh rate is 75 Hz, or 37.5 Hz per eye. That produces an acceptable, stereo 3D (S3D) experience, using an anaglyph technique, but with the screens just a few centimeters from your eye you see pixels, and that’s why it looks grainy. At a distance that resolution would be integrated by your optical nerve system and brain and it would look smoother. The resolution problem is one that will yield to Moore’s law, but not quickly. As the resolution goes up, so does the compute load and both have to be handled simultaneously. However, the current state of the art is acceptable, and even enjoyable in certain cases.

The more serious problem, which Moore’s law can’t fix, is VR or sim-sickness. A user will experience it if engaged with a fast-paced game like a first-person shooter (FPS) where you are running, turning, climbing, etc. The cause is the disagreement between what your eyes are telling you and what your inner ear is reporting. It’s the same problem some people get from sea and travel sickness.

In VR however, it’s just the opposite of motion sickness, but with the same disagreeable effect. In VR your eyes tell you you’re running and jumping through a world, but your inner ear says you’re sitting at a desk.

Unless you play a game where the protagonist is still most of the time, or moves slowly, there’s not much developers can do about it, and higher-resolution, faster processors won’t help—it’s just the way some of us are built. There is hope. Flight training instructors tell recruits throw up till you can stay up. The point being, you can train your brain to overcome it, but it takes a lot of practice.

I’ve been experimenting with it, and can sadly report it is a real thing. At first I thought, I must be getting old; I don’t feel so good. I was playing Half Life 2 with Oculus (DK2) and experienced, for the first time, VR sickness. When I first started flying as a test engineer, a long time ago, I got air sick the first time, and felt a little queasy a couple of flights afterward, but learned to deal with it to where it doesn’t bother me, and I fly a lot on business now. I thought, till the other afternoon, sim-sickness was BS and only affected the wimps. Guess what, I just joined the wimp society.

Now I’m confident I can train myself out of it. And HL2 is just a great game so it won’t be hard duty. What I’m not so sure about is, will I only be able to deal with HL2 and lose it on some other game.

I asked some of my friends in the industry if they’ve experienced it, and to my surprise everyone one of them said they had. One guy told me he gets it even with a normal monitor if he plays first person shooters long enough. That gave me pause and I realized he was right, I had experienced some discomfort with my face up close to the monitor, maybe 12 to 15-inches away, but I was so intent on getting the bad guys I ignored it till the quest was won. Then when I stood up, I thought, whoa, I need to eat something; my stomach doesn’t feel so good.

One commentator suggested VR sickness be promoted like a roller coaster ride—this is so great it’ll make you puke.

Oculus, Sony, Samsung, Immersion, Seebright, and the other dozen or so head-mounted display (HMD) providers are well aware of this issue, and most are calling on the game/ application developers to take it into consideration when designing the game. But the developers can’t control how a player moves in a game— well they can, but it’s not a very fun game when they do.

One of the big improvements in the Oculus Rift DK2 is its positional tracking. In the first model if you leaned forward with your body your virtual head would not move correctly. That contributed to sim-sickness. When you move to look at something (in a virtual space) you make subtle movements, even if just shifting in a chair; rotation alone can’t capture that.

Oculus fixed that by adding an IRLED array into the DK2. The array is tracked by the camera (that sits atop the monitor) and it can capture at 60fps. The positional tracker helps, but you’ll still feel the effect of sim-sickness if you move in the virtual world too fast— your brain just needs time to process and catch up with all the confusing input its getting. And for some reason the positional tracking volume inside of Half-Life 2 is artificially limited, but it can be fixed by increasing the vr translation limit to 100.

So what do we do? Take it easy, that’s the best advice I can give. If you’re in a fast-paced FPS and your HMD has you cut off from local reference points, take a break, pull the HMD up, lean back, breathe deeply, and look around the room to get your bearings. No one who has ever experienced it will think less of you or call you a wimp. And if anyone does, give them the HMD add tell them to get it on.

I wonder how many times Luckey and Carmack got sick…