Explained: How does VR actually work?

Mind blown by VR headsets? Here's how the tech tricks your brains
Explained: How VR works

How does VR work? How does wearable tech make you think you're standing on Mars when you're actually about to bump into the kitchen counter? We'll be explaining how virtual reality headsets work here.

Let's start with some basics.

The headset set-up is being used by Oculus, Sony, HTC, Samsung and Google, and usually requires three things. A PC, console or smartphone to run the app or game, a headset which secures a display in front of your eyes (which could be the phone's display) and some kind of input - head tracking, controllers, hand tracking, voice, on-device buttons or trackpads.

Essential reading: Playstation VR review

Total immersion is what everyone making a VR headset, game or app is aiming towards - making the virtual reality experience so real that we forget the computer, headgear and accessories and act exactly as we would in the real world. So how do we get there?

The basics

what is virtual reality

VR headsets like Oculus Rift and PlayStation VR are often referred to as HMDs and all that means is that they are head mounted displays. Even with no audio or hand tracking, holding up Google Cardboard to place your smartphone's display in front of your face can be enough to get you half-immersed in a virtual world.

The goal of the hardware is to create what appears to be a life size, 3D virtual environment without the boundaries we usually associate with TV or computer screens. So whichever way you look, the screen mounted to your face follows you. This is unlike AR which overlays graphics onto your view of the real world.

The future: Virtual reality versus augmented reality

Video is sent from the console or computer to the headset via a HDMI cable in the case of headsets such as HTC's Vive and the Rift. For Google's Daydream headset and the Samsung Gear VR, it's already on the smartphone slotted into the headset.

how does VR work

VR headsets use either two feeds sent to one display or two LCD displays, one per eye. There are also lenses which are placed between your eyes and the pixels which is why the devices are often called goggles. In some instances, these can be adjusted to match the distance between your eyes which varies from person to person.

These lenses focus and reshape the picture for each eye and create a stereoscopic 3D image by angling the two 2D images to mimic how each of our two eyes views the world ever-so-slightly differently. Try closing one eye then the other to see individual objects dance about from side to side and you get the idea behind this.


One important way VR headsets can increase immersion is to increase the field of view i.e. how wide the picture is. A 360 degree display would be too expensive and unnecessary. Most high-end headsets make do with 100 or 110 degree field of view which is wide enough to do the trick.

And for the resulting picture to be at all convincing, a minimum frame rate of around 60 frames per second is needed to avoid stuttering or users feeling sick. The current crop of VR headsets go way beyond this - Oculus is capable of 90fps, for instance, Sony's PlayStation VR manages 120fps.

Head tracking

what is VR

Head tracking means that when you wear a VR headset, the picture in front of you shifts as you look up, down and side to side or angle your head. A system called 6DoF (six degrees of freedom) plots your head in terms of your x, y and z axis to measure head movements forward and backwards, side to side and shoulder to shoulder, otherwise known as pitch, yaw and roll.

Hands-on: Google Daydream View review

There's a few different internal components which can be used in a head-tracking system such as a gyroscope, accelerometer and a magnetometer. Sony's PSVR also uses nine LEDs dotted around the headset to provide 360 degree head tracking thanks to an external PS4 camera monitoring these signals, Oculus has 20 lights but they are not as bright.

Head-tracking tech needs low latency to be effective - we're talking 50ms or less or we will detect the lag between when we turn our head and when the VR environment changes. The Oculus Rift has an impressively minimised lag of just 30 milliseconds. Lag can also be a problem for any motion tracking inputs such as PS Move-style controllers that measure our hand and arm movements.

Finally, headphones can be used to increase the sense of immersion. Binaural or 3D audio can be used by app and game developers to tap into VR headsets' head-tracking technology to take advantage of this and give the wearer the sense that sound is coming from behind, to the side of them or in the distance.

Motion tracking

VR explained

Head tracking is one big advantage the premium headsets have over the likes of Cardboard other mobile VR headsets. But the big VR players are still working out motion tracking. When you look down with a VR headset on the first thing you want to do is see your hands in a virtual space.

For a while, we've seen the Leap Motion accessory - which uses an infrared sensor to track hand movements - strapped to the front of Oculus dev kits. We've also tried a few experiments with Kinect 2 cameras tracking our flailing bodies. But now we have exciting input options from Oculus, Valve and Sony.

Oculus Touch is a set of wireless controllers, designed to make you feel like you're using your own hands in VR. You grab each controller and use buttons, thumbsticks and triggers during VR games. So for instance, to shoot a gun you squeeze on the hand trigger. There is also a matrix of sensors on each controller to detect gestures such as pointing and waving. Touch is launching soon.

Headset head-to-head: HTC Vive versus Oculus Rift

It's a pretty similar set-up to Valve's Lighthouse positional tracking system and HTC's controllers for its Vive headset. It involves two base stations around the room which sweep the area with lasers. These can detect the precise position of your head and both hands based on the timing of when they hit each photocell sensor on both the headset and around each handheld controller. Like Oculus Touch, these also feature physical buttons too and incredibly you can have two Lighthouse systems in the same space to track multiple users.

Other input methods can include anything from hooking an Xbox controller or joystick up to your PC, voice controls, smart gloves and treadmills such as the Virtuix Omni, which allow you to simulate walking around a VR environment with clever in-game redirections.

Eye tracking

FOVE VR headset hits Kickstarter

Eye tracking is possibly the final piece of the VR puzzle. It's not available on the Rift, Vive or PS VR but it will feature in FOVE's very promising VR headset. So how does it work?

Well, an infrared sensor monitor's your eyes inside the headset so FOVE knows where your eyes are looking in virtual reality. The main advantage of this - apart from allowing in-game characters to more precisely react to where you're looking - is to make depth of field more realistic.

In standard VR headsets, everything is in pin-sharp focus which isn't how we're used to experiencing the world. If our eyes look at an object in the distance, for instance, the foreground blurs and vice versa. By tracking our eyes, FOVE's graphics engine can simulate this in a 3D space in VR. That's right, blur can be good.

Headsets still need hi-res displays to avoid the effect of looking through a grid. Also what our eyes focus on needs to look as life-like as possible. Without eye tracking, with everything in focus as you move your eyes - but not your head - around a scene, simulation sickness is more likely. Your brain knows that something doesn't match up.


Shop for VR headsets on Amazon

Oculus Rift
Oculus Rift
$599.99
PlayStation VR
PlayStation VR
$399
HTC Vive
HTC Vive
$799
Samsung Gear VR
Samsung Gear VR
$97.98

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15 Comments

  • Giggs says:

    Great article! I want to get excited about this, but need to get my hands/eyes on one. Do they have many demo models in stores yet (US)?

  • Socia_Media_USA says:

    Oh that's amazing. We really love your articles about these technology and we are very eager to share them on Affimity's Digital Life...

  • azel says:

    wow i wanna to try this device, that pretty amazing

  • DougA says:

    They look great for gaming, but an alternative for them to work as a computer monitor for visually impaired people would be great! - Does this exist already?

  • diesel17018 says:

    This has made me want to make a career of building and advancing this type of technology.  What type of schooling do I need to make this possible?

    • j03y0 says:

      Computer Science most likely

  • Gogeenos2743 says:

    I recently went to an AT&T store and picked up a virtual headset and man was I blown away these things were amazing the video feed was an aquarium and I felt like I was inside the tank and at one moment my wife laughed at me coz I ducked down and she asked why I did that and I told her that a sea turtle was swimming right at me. But these are really amazing now I'm in the market to but me and my wife a pair.

  • gamelocker says:

    i have a question in mind plz solve it:

    1. can we use vr headset on any device?

    2. what are requirements for using vr on a device?

    • JuneBug says:

      No you can't use any device. Oculus Rift requires a PCWORLD  (requirements vary) or  PS 4. The Samsung VR requires a galaxy s6, s7 or note 5, and the LG headset requires an LG V10 I beleive.

  • InvisionVR says:

    Great article! The future of Virtual Reality is here :) Great collection of Affordable, Mid-Range and High End VR headsets at https://invision-vr.com

  • ranger says:

    All I wanted to know. Thanks for the great article.

  • SeabeeJim says:

    I am interested in VR. I have a Mac desktop and an Ipad. Is there a unit I can use with them?

  • Jenson says:

    I wanted to know what VR Headsets meant and how they work.

    Now I know the basics. Thank you.

    I now wonder how Donkey Kong will play in VR mode... :)

  • cherry23 says:

    VR box is amazing, recently ,i saw vkworld t1 plus with VR box, You can assemble it under the instructions and enjoy endless VR resources

  • jnelson1 says:

    Can someone please tell me if I can buy any VR and it will work with a PlayStation? Or does only the PlayStation VR work? I wasn't sure if I could buy any model and then connect it via Bluetooth or something like that. 

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