What is VR and how it works?
In essence, the goal of VR is to create an immersive multimedia experience, putting you in a world, real or imagined, and letting you interact in that world. The ultimate goal is presumably like that scene in Disney’s Tomorrowland where Casey Newton experiences the “journey” to “Tomorrowland” whenever she touches the pin. As we take in most information of our surroundings via our vision, the pursuit of VR begins with fooling our eyes enough to believe that we actually are in a reality separate from the real world.
To do this, special stereoscopic displays that look like goggles are used, with two separate images sent to each eye, similar to the concept of 3D. This creates a more complex but more believable perception of depth. Some go the extra mile of immersing our other senses into the experience, but few go beyond providing earphones for the sound department, let alone the full immersion that allows us to run, climb and all that without bumping into anything in the real world.
Of course, that sort of full immersion is not feasible now, just as VR as a whole was not feasible 5 decades back. Even in the visual department, there are some issues that still need ironing out.
Our eyes are very used to the smoothness of real life; whatever registers in our sight changes with every minute movement of our eyes and head. VR head-mounted displays (HMD) aren’t as perfect just yet, as there will be a slight delay between when we move our heads and when the display in the HMD adapts accordingly. This lag, however minute, will contribute to a nauseating feeling currently inevitable with extended periods of VR; the brain is trying to convince itself that the reason you’re not seeing change in your field of view immediately is because you’re not actually looking at real life.
Then there is the issue of refresh rates and frame rates. Oculus and Valve agree that whatever we see in VR needs to be rendered at at least 90fps for a smooth, nausea-free experience, but that will require some powerful hardware, and such power can be difficult to achieve depending on the type of HMD. The display that is the window into the world of VR itself needs to be capable of a refresh rate equal to or greater than the framerate of the content. If either fails, not only does it result in an experience that isn’t immersive enough, it also means that nausea will come knocking on your door again. This is simply because the brain isn’t used to having to deal with refresh rates, and 90FPS seems to be a frame rate that is too fast for our eyes to perceive the individual frames.