Slayemin's Working Theory on VR Motion Sickness

[Slayemin]

@Crow87;394768

Very good writeup. Do you mind if I share my own limited personal findings?

I find lighting is a very important part of causing/preventing motion sickness. In all of the experiences and tests we have worked on, we find that bright scenes with limited points of contrast are the biggest culprits for causing motion sickness. Particularly a cold-sweating, deeply uncomfortable sense of malaise type motion sickness. Bad stuff. Take for example, a bright white room, with white furniture and white fixtures. Without anything to balance out the contrast in the scene, we’ve found that this leads to sickness very quickly.

However, a dark scene with limited contrast doesn’t seem to have the same effect. There’s just something deeply uncomfortable about bright scenes.

Another area I feel contributes pretty significantly to the motion sickness is audio design. Loud droning noises in particular seem to trigger something in me, and other people I have tested with. Perhaps its something to do with disturbing the inner ear, but the effect is a sense of uncomfortable claustrophobia and inevitable sensitivity to motion sickness. It could be more psychological than physiological, but it definitely seems to play a part.

Just my 2 cents.

Interesting. So, a padded white room with a constant droning hum would cause people to feel sick?

I’d be interested in testing this to see for myself.

@osakaro;394853

how do you use UMG in VR?

Very carefully. Each eye can see half of the slate workspace, so when you place your UI elements, you have to double it up – one for each eye. The placement needs to be done very carefully. You have to find the eye center position X/Y values for each eye. When placing UI elements, the Y values need to be exactly the same, but the X values will be done for each eye. There’s an X value which will cause the UI element to be ‘neutral’ position (centered on each eye pupil). Keep in mind that since you’re working stereoscopically, changing the X values from the neutral base value will cause the UI element to appear forward or backward on the depth axis. You also need to keep in mind that placing UI elements at the edges of the eye lens / screen will NOT work – this causes the UI element to be seen from the corner of your eye, and if you move your eye to look at it, it disappears.

The other thing to keep in mind is that any UI elements you place within slate will be rendered last, such that they overlay anything else. When you have a stereoscopic UI element, such as a targeting reticle which is floating about 3-4 feet away from your face, and you then look at a wall which is 1-2 feet away from your face, the reticle will appear to be floating within the wall but still be very visible. This will appear as ‘wrong’ within the scene, so be aware of this.

Like I said, you can use UMG & Slate to do UI within VR, but you should use it very sparingly. If you’re using buttons or displaying data, you’re probably doing it wrong. Treat the slate UI as if the player is wearing a bionic eye and you’re rendering stuff onto the surface of their eyeball. Also, keep in mind that people have blind spots at certain positions of their eye, so rendering a small UI element at this location will not appear visually unless the player is looking directly at it. You can find these blind spots yourself by getting a sheet of paper, drawing an X and a dot about 2-3 inches apart, covering one eye, focusing on the X, and moving the paper forward and backward until the dot disappears.

Anyways, best practice is to put UI information into the environment instead of into a screen surface, but it’s not a fixed rule. Just be aware of the limitations and draw backs I mentioned.