Frame rate plays a role - especially when it drops down below targets and stutters, which does happen irl, but designing the experience to avoid motion sickness from the ground up is what makes the difference. Keeping something stable in the view that moves along with head pose like a HUD element while everything else around you is moving makes a huge difference. Seeing the world around you in motion from inside a car with the stable windscreen will be much easier than zooming around through freespace even at 120hz for most people until they get comfortable with the sensory mismatch. I have heard several interesting approaches to acclimatization and can recommend this [1] if you are affected & am told positioning a real fan blowing air on you while in the headset will orient your proprioception in a way that helps.
Motion sickness is mainly caused by framerate and given that VR is extremely taxing compared just displaying on a monitor is often the issue. It is hard to drive two screens at once at 120 or higher FPS
For me it helps to have as much of a view of the outside as possible. Feeling the wind helps also. If I'm in the back seat looking mostly at the interior of the car, my inner ear senses motion but my eyes tell me I'm stationary. I think those conflicting inputs are the cause of most motion sickness.
Much less of an issue for me when I'm in front looking out the front window.
I get very motion sick, but I do fine in VR. The only time I get sick with VR is when the motion is not correlated with my head movement.. for example, if you turn the camera with a controller.
>The hardware doesn't matter; some people just cannot stand certain forms of stimulation-without-movement that occurs with virtual reality
While it won't help every case, for the vast majority the motion sickness is alleviated when the head tracking is better (accurate positional tracking and low latency).
You can make pretty much anyone feel sick if you add enough lag to the display.
Depends. I get horrible carsickness just riding a bus or a plane, so I get some motion sickness in VR no matter how high of FPS it is, no matter how low the latency. I sometimes get motion sickness playing games on my monitor too though, so I'm definitely in the most susceptible category for this stuff.
Like other said though, the worst of it goes away after using it a few times. I noticed though that if you're really susceptible to motion sickness, you basically need to adjust to every type of locomotion or movement individually -- and any vehicles or cockpits are still totally unviable for me still, from No Mans Sky to American Truck Simulator.
Though it's not just one kind of locomotion either -- I adjusted to head-position-relative smooth locomotion with a joystick on a flat surface at a walking pace, but what about downhill at a running pace, on horseback? Then I have to spend another week getting used to THAT. Or what about smooth locomotion circle strafing in a dungeon around a bunch of skeletons? Another week. And I still can't handle any camera rotation at all.
First hand here, the DK1 was brutal, DK2 was ok. Besides what is actually being played another major variable is the machine driving it. If the frame rate is less than ideal it will cause issues.
The thing is I got motion sick in the early 90s playing Wolfenstein 3D and so did others. On like a 15" monitor. There were stories about people vomiting back then. When is the last time you heard of someone getting dizzy and puking after play call of duty? I haven't heard of FPS motion sickness since the 90s.
All of the technical nuances related to what invokes motion sickness in VR have been exhaustively studied and are actively worked on. However my experience makes me suspect there is some adaptability involved as well. I've spent most of the past decade in dense urban cores and if I haven't been in a vehicle in a week or two, a cab to the airport leaves me close to puking.
From a commercial standpoint the important thing is don't give your customers a shaky first demo that leaves them with dry heaves. Give something neutral like sitting in a movie theater, and gradually ease them in.
I've experimented with our own game engine and VR sickness. When the view doesn't accelerate relative to your real-world position, there is no issue. The problem starts when you're using external direct movement control, such as a mouse and keyboard. Moving forward and suddenly starting to move backwards is slightly uncomfortable. Rotating your head while rotating the mouse in the same direction is the worst for me.
It's the inverse of car sickness, and affects some people but not others. My coworker has no issue using full FPS mouse/kb controls within VR.
A windowless vehicle makes it worse, because you don't see any movement, you just feel it. As klibertp said....
> Motion sickness comes from the conflict between your eyes and the part of your ear which tells you which way is up and lets you stay in balance.
If there's no windows, then your eyes will say "We're not moving", but your inner motion sensor in your ear will say "We're definitely moving", and you'll create motion sickness.
It's for the same reason some people feel motion sickness in some VR apps that involve movement in the virtual world that doesn't match your real world movement, such as driving a car in VR. Your eyes say "We're moving", but your ear says "No we aren't!", and the discrepancy triggers motion sickness.
The ELI5 version is that if the motion your eyes see doesn't match what the movement/balance sensors in your inner ear feel, your brain thinks the mismatch is because you ate something you shouldn't and begins inducing vomiting. Motion sickness.
The result is that games where your real world movement matches the game world movement, such as games like Beat Saber, MOST people feel fine. But in a game where the movements don't match, such as any racing or flying game, and any game where you move by holding a button or stick, motion sickness sets in VERY quickly for most people.
Lag between moving your head and moving the image creates motion sickness because it creates the mismatch. Getting head tracking latency down to zero frames was a real innovation on the Oculus Rift and is an absolute requirement for any VR headset. Secondly, the frame rate needs to be high. The original Rift was 90 fps. Valve Index is up to 144 fps. Quest 2 I THINK is designed for 80 fps IIRC.
In some games, like MS Flight Simulator, it's not really possible to achieve the 144 fps my Index supports without turning the graphics wayyyy down. In this case, the software performs dynamic reprojection when I move my head. Essentially, it just moves the last frame rendered frame around the display to mimic what its movement should be. Of course, it has the side effect that the edges of vision are just black if there's no rendered data, but it's enough to prevent motion sickness when looking around the cockpit at only 40 fps.
Naturally, that's moot when I actually start flying the plane. As soon as the plane starts moving, I feel queasy.
But with enough practice, it can be overcome. The human brain is quite adaptive and can eventually learn to not care about the visual/physical mismatch.
4: Many people have reported that slowly conditioning themselves to be resistant to motion sickness inside VR has also helped them become more resistant to motion sickness outside of VR. As in, some VR users are saying "I can read in the car for the first time!"
I emphasize slowly because trying to muscle through motion sickness has the opposite effect and can even lead to giving yourself an aversion to VR that resembles having an aversion to tequila after a "bad tequila night". Some people who have done this to themselves get sick from just the smell of a headset.
We already have virtually zero latency in VR at the moment thanks to predictive tracking and rewarping of the frames to the predicted head pose and direct driver support.
The motion sickness is mostly coming from vection now, when you move in VR but not in real reality. It's an active area of research, people are experimenting with things like reducing the FOV while moving, using interactive overlaid grid to pull the scene around, etc.
Anecdotal evidence: I used to get motion sick in cars, but after playing hundreds of hours in Beat Saber on my Quest, no more. I can bear road trips just fine.
People don't get motion sick from the fps, latency and fov of current gen (PC) VR (90 fps, ~0ms, ~100°). They get motion sick from vection and maybe from vergence accomodation conflict.
[1] https://medium.com/@ThisIsMeIn360VR/motion-sickness-and-the-...
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