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Movement in VR

VR’s greatest strength is also the source of one of its most prominent problems. Virtual reality headsets allow us to experience content in the most immersive capacity. Put on your headset and be instantly transported to a new world. Naturally, the content creators who were first to the scene wanted to show everyone the thrill of VR and we saw games featuring flying, racing, swimming, and floating in space. However, with this movement mechanics emerged a big problem. These games were making people sick.

Visual Vestibular Mismatch occurs when the sense of balance in your inner ear does not match up with the input from your eyes. This can lead to symptoms of dizziness, vertigo, imbalance, and lightheadedness. If you are playing a spaceship racing game while wearing a VR headset and sitting still on your couch, is it any surprise that these symptoms will emerge?

Some people are lucky enough to feel little or no motion sickness in this situations. Some others can afford to buy the high end hardware that can simulate in-game motion IRL and mitigate this risk. For the rest of us who don’t like feeling dizzy from our entertainment, we need to be more discerning in our choice of VR games. In order to find the best solution, I will describe the potential motion sickness and immersion of a few popular VR movement mechanics (assuming that high-end immersive hardware is not being used.)

If you want your character to walk around in VR, you can either use a joystick or you can actually walk around your play space. Walking around your place space to move your character is excellent, but it is limited by the size of your space. Given that most VR gamers do not have room scale capability, many games use joysticks for movement instead. Moving with a joystick does not feel especially immersive as your brain knows that you aren’t moving your legs and motion sickness can occur, especially at faster speeds.

Joystick Walking Score: Immersion=2, Sickness=4.

Seeing the flaws involved in VR walking, many developers have opted to use teleportation as a primary way to get around. By instantly transporting the player to whatever area they’re pointing at with the hand controller, there is no sense of visual vestibular mismatch. However, as teleportation is essentially moving from one static state to another, there is not as much excitement in the action.

Teleportation Score: Immersion=1, Sickness=1

In order to work around the fact that joystick walking in VR isn’t very immersive, another option is to have the in-game character sitting or standing in a moving object, such as a cart or a car. This way, when your in-game character moves, your brain can recognize that it’s because you are in a vehicle and is less likely to question that your other sensory input would suggest that you are in fact standing still. This works to some degree, but it still causes problems if the cart were to rapidly turn a corner, tilt, speed up, or do anything else other than slowly advance.

Moving Cart Score: Immersion=2, Sickness=3.

Climbing is VR is a great way to have little to no motion sickness while remaining deeply immersive. As you grab hand holds and pull yourself forward, your visuals match what your brain would expect from your motion.

Climbing Score: Immersion=4, Sickness=1.

Sources: https://art.mallinson.ca/thesis/c3/