Quality of Life Adjustments in VR

1. Quality of Life Adjustments in VR

This tutorial has been verified using Unity 2019.4.12f1 LTS

In this tutorial, we'll explore some best practices to keep users comfortable in your virtual world.

When your user first "arrives" in the virtual world, it’s a good idea to give them some time and space to get adjusted. Consider integrating an exercise to familiarize them with navigating and interacting with the environment.

The camera's field of view (FOV) should match, as closely as possible, that of the target hardware. This allows a more natural view of the virtual world and, in some VR SDKs, is already permanently set to the appropriate value. An incorrect or extreme FOV is especially distressing when the camera is in motion, or in augmented/mixed reality scenarios.

Another pitfall to avoid relates to stereo viewing. It's a good idea to maintain a minimum distance between objects and the camera to allow the user's brain/vision system to merge what both are seeing into a stereo view. Having objects too close causes too great a disparity in each eye’s view for the brain to be able to merge them, creating the feeling that something's about to enter the user’s field of vision. This also causes clipping issues with the Camera. Clipping issues can also be resolved by adjusting the Camera's near plane distance (Figure 01).

Figure 01: Adjusting the Near Clipping Plane to help with clipping issues as objects approach the Camera/eyes

Certain Camera moves should be avoided altogether, such as rolls (especially barrel rolls). Another cause of discomfort in VR is the disconnect between the motion of the Camera and that of the user's body — for example, acceleration and deceleration of the camera when the user isn't physically moving. Imagine stepping onto or off of a moving sidewalk or an escalator. Both require a sort of reorienting of momentum when entering or exiting. Now imagine doing that every time you wanted to move anywhere in the real world.

Teleportation is an elegant solution to the challenges of movement over large distances in VR. Your user simply looks or aims (depending on the control system) where they want to go and initiates a teleport. When teleporting, the user should not be able to see the change in position, even obscured or vignetted. Instead, try a quick fade out before fading in with the Camera in the new position. Another option is to use doors that lower around the user, or close in front of them, raising/reopening once in the new position.

If you must have the user's avatar move without their head or body moving, then restricting the FOV (if the SDK for the target hardware allows it) can help ease or prevent VR sickness.

2. Conclusion

Extra care when designing your virtual experience can mean the difference between users needing to stop after a few minutes or being able to stay in-world for hours.