There are many terms used to talk about Virtual Reality and related technologies like Augmented Reality and Mixed Reality, so we have put together a handy quick reference below to help keep you up to speed with this growing tech segment.

360 Video A 360 video simply lets you view a scene looking forward, behind, and to both sides while seeing the entire projection in context from each angle. If you’ve ever used Google Earth, where you can zoom down to street level and pan the image from your own point of view as through you were standing at the scene and turning your body in a complete circle to see a 360-degree view of the area, you have experienced a 360-degree view.

AR Augmented reality is similar to mixed reality in that it blends a virtual environment with our own physical surroundings. Augmented reality uses a device to overlay digital virtual objects or content, such as data, video, and sound onto our view of the real world around us, enabling interaction with the physical world as digital content as is imposed on it. In this scenario, the digital content supplements rather than responds to the real world.

Asynchronous Timewarp This is a technique used to modulate low persistence. With asynchronous timewarp, intermediate frames are generated to bridge the content displayed when framerates drop below a level that delivers a smooth transition between a displayed image and the next image to be displayed.

Blind Spot Humans have a natural blind spot when it comes to viewing anything beyond the limits of peripheral vision. Extended Reality headsets also can have a blind spot, defined by the edges of the display.

Directional Sound Similar to stereo, which can project sound from one speaker or another, directional sound appears to come from a specific virtual object, place, or creature. At a minimum, directional sound requires stereo headphones designed to deliver a directional sound experience.

Discrete Graphics Processor While your computer’s CPU may be capable of doing some decent graphics processing, there are benefits, especially for gamers, to having a discrete or dedicated graphics processor that works independently from your computer's primary graphics card. Discrete graphics can be added as a separate chip on your mother board or gaming system board. The benefits of dedicated graphics are, it allocates video processing to that specific graphics card rather than using your system’s central processor. This can result in better system performance, and much better rendering of graphics.

Extended Reality A term that refers collectively to any type of device used to deliver a virtual, augmented, mixed, or other type of altered reality experience.

Eye Tracking Eye tracking not only helps extended reality devices to deliver an exceptional visual experience based on where the user is looking, it really makes the experience feel more immersive. With eye tracking, your avatar’s eyes will respond just as your eyes do as you move through a virtual world. For instance, your avatar’s aim will be based on what you’re looking at. Eye tracking also adds another dimension to player interaction as other characters can respond based on your facial cues.

Field of View Simply translated, field of view is what you see. With an extended reality device, the field of view is, in part, dependent on the display screen, proximity of the viewing lens to your eyes, and the size of the viewing lens. Lens thickness also is a factor. Some headsets enhance the field of view by allowing users to adjust the headset interpupillary distance (IPD), the distance between the viewing lenses across the bridge of the nose, for the clearest image.

Fish Tank VR Somewhat like lurking, perhaps without the negative connotation, you can have a virtual experience, without actually being a part of the action. The virtual world doesn’t acknowledge your presence there, it doesn’t interact with you and you don’t interact with it. You are strictly an observer.

Focal Length Focal length is a measurement of optical distance. It refers to the eye’s ability to perceive objects at varying distances while keeping the objects in focus. Short focal lengths give you a wide view, think big picture less detail, like a cityscape. Long focal lengths give you a narrow view; a smaller picture with more detail, such as a portrait.

Haptics A common example of haptic feedback is the sensation you sometimes feel when you interact with a screen on a digital device. For example, a digital button may employ haptics to make the button response feel more like pressing a button in the real world. Haptics are what give game controllers an added layer of realism. Extended reality systems that use hand controls, joy sticks, etc., can respond with haptic feedback making the interaction feel more real to the user.

Head Tracking Head tracking helps extended reality devices to orient a virtual environment to the user’s point of view. For example, if you’re engaged in a virtual battle, the device headset may use cameras, or other technology to keep track of your virtual location, tracking 6 degrees of freedom 6DOF, and the position of your head, tracking 3 degrees of freedom 3DOF, in order to display your battle opponent in the correct position relative to where you are looking.

HMD A Head Mounted Display is basically a small computer display, worn as a headset, which uses one or two lenses to depict a computer-generated image or environment. Many extended reality systems involve the use of a head mounted display to transport viewers in the various types of virtual realms. Some HMDs have built in cameras for tracking the user’s position relative to the virtual experience.

Image Distance Extended reality headsets use a combination of lenses, display screens, and light to render images in the virtual space. The goal is to display images at a size and distance that mimics real life, things appear smaller when farther away. Distance also can refer to the controls a user employs to interact with the virtual space. For example, hand controllers that are meant to sync with the user’s hands should appear in the virtual space at a realistic distance from the user’s perceived position within the virtual environment. If the controls appear to be too close or too far away based on the placement of the users actual hands, the headset is displaying a distorted image distance relative to the user.

Inter-pupillary Distance The distance between the pupils of both eyes, or the distance between a headset’s viewing lenses across the bridge of the nose. IPD, is a key factor in a headset’s ability to correctly display, and a human’s ability to accurately perceive, stereoscopic 3D images.

Judder Judder is perceived when a user is in motion and the frame rate of the headset’s digital display is not fast enough to refresh the digital image or view at the same pace of the headset motion. The result is a blurred or smeared image similar to what you would see if you took a picture while running past your subject. Over time, this can cause a user to experience the sensation of motion sickness.

Latency Is a two-factor component of the extended reality experience. First, it is defined as the amount of time that elapses between when the user initiates some kind of input, say using a controller to fire a weapon, and when the display actually shows the weapon firing. Second, latency can be the cause of motion sickness in a virtual experience. If the display updates too slowly as you move through a virtual environment, let’s say you duck to avoid an opponent’s sword, and the display doesn’t update in close to real time, your perceived view won’t be in sync with your actual body position and this “imbalance” is what causes the sensation of motion sickness.

Low Persistence VR content, like film, is a series of images that appear at a particular rate in sequential order to generate a virtual environment. Persistence refers to how long any one image remains visible before the next image appears in sequence. If a single image’s persistence is too long and the next image appears before the previous image disappears, the viewer sees a blurred presentation. If the Persistence of a single image is to short, and disappears before the next image in the sequence appears, the viewer sees a lag, also called latency, in the content being displayed. Either way, continuity of the depicted environment is compromised and results in a distorted view and experience for the viewer.

Motion Platform A motion platform is a device used to provide motion that mirrors movement inside a VR environment. It can be used to simulate driving or flying and provide differing degrees of freedom in their motions.

One To One Movement This occurs when your movements sync exactly to your virtual avatar.

Position Tracking This is all about where you are both in the play space and in virtual space. Using a variety of technologies, extended reality devices can detect and track your movements to deliver a better, more responsive VR experience, and in the case of HTC Vive, make sure you don’t collide with real world objects not seen in your virtual experience.

Refresh Rate If you’ve ever drawn a series of stick figure images one per page in a notebook, and then flipped through those pages in quick succession so the images appears to move, like an animated cartoon, you are using a rapid refresh rate to simulate the stick figure moving smoothly through time and space. Viewed slowly, one page at a time, the figure appears only as a series of static images. Extended reality headsets with higher refresh rates, give the user a smoother view, more realistic virtual experience.

Social VR Let’s say you want to have dinner with your siblings, who are currently living in other parts of the country. Using a VR system, you could meet with them in a virtual restaurant setting and have a simulated meal together interacting with each other via your chosen avatars.

Spatial Desync A number of things can cause or result in spatial desync. If the virtual environment is not an accurate representation of the real world causing a disruption in your movement or what is displayed. When objects in the virtual environment don’t respond as they would in the real world, for example, if you are walking around a horse and your avatar walks through it. Or, if you kick a virtual opponent in the ribs and your Avatar simply flails its left arm. Any of these occurrences are considered spatial desync.

Stitching Stitching is a process in which multiple individual images or videos are digitally merged, or stitched, together to create a single seamless image or video resulting from the individual parts. In an extended reality experience, images or videos that are stitched poorly so the “seams” of the individual source content are visible in the final combined image or video result in a poor visual experience for the user.

Virtual Space In short, this is your game space. It’s a digitally created non-physical environment in which the real world and a computer generated virtual world appear to combine, or overlap, and in some cases interact. Through the use of a headset and controller, a VR, AR, or MR user may perceive or experience themselves as a participant in a virtual space.

VR Sickness Also known as motion sickness. Inconsistent frame rates can make your screen flicker like a bad TV. This can, in some people, cause a sense of motion sickness. A good-quality system with high-level consistent frame rates doesn't usually cause motion sickness in most people.