XR Glossary

What does XR mean? Or FoV, AI, Mocap or CAVE? What is the difference between VR, AR and MR? To answer all of these questions and more, we collected all of the essential XR related words and their meanings together in this brief XR Glossary!

General

XR = eXtended Reality (syn. X Reality, Cross Reality)
XR is an umbrella term, which includes VR, AR and MR. Thus, XR represents everything between our reality to full virtual reality, and all mixtures of reality and virtuality in between.

VR = Virtual Reality
Virtual reality is a computer-generated three dimensional simulation that can mimic reality or be something totally different. Virtual reality is usually experienced through a VR-headset as a visual environment.

AR = Augmented Reality
Augmented reality refers to adding computer-generated virtual elements and data to a real environment for example through a smartphone screen or AR-glasses.

MR = Mixed Reality
Mixed reality is between VR and AR, where reality and computer-generated virtuality exist together in different proportions.

AI = Artificial Intelligence
Artificial intelligence is the ability of machines to work like human intelligence for example by searching and analysing data and developing solutions from it without being strictly coded to the task.

Avatar
Avatar is a profile character or picture that visually represents the creator of the profile on the internet. Click here for an example image with three virtual reality avatars in AltspaceVR.

Cybersickness
Cybersickness refers to a nauseous feeling after using VR-headset. Usually it is caused by motion sickness where human senses conflict with each other, a person sees they move in VR, but their physical body stays in place. Cybersickness can also be caused by low resolution, low frames per second or unfocused view.

Immersion
Immersion refers to something unreal to feel real, in virtual reality it is the perception of being physically in the virtual environment.

Play area
Before using a VR-headset, a physical area is determined in which the headset works. If a person with the VR-headset goes outside the area, the headset informs it with a virtual safety net or they stop the ongoing activity.

Social VR platforms
Social VR platforms are designed for people to meet each other and have fun like play games or watch movies. It is characteristic for social platforms to have a lot of choices and abilities to modify the environment. People come to these VR platforms mostly in their free time. However, some of these platforms are also possible to categorize as collaboration platforms. Examples: AltspaceVR, Mozilla Hubs, VRChat, Rec Room, Bigscreen. 

VR collaboration platforms
VR collaboration platforms are designed for work environments for example to workshops, meetings and conferences. Modifying and experimenting is at minimum, but easy access to things like screen share and drawing is provided. Part of these platforms are also possible to categorize as social platforms. Examples: AltspaceVR, Glue, Mozilla Hubs, Engage, Spatial, MeetinVR, Rumii.

360-image / 360-video
360-image or -video is an image or a video from 360 degrees, thus it depicts everything around one point in an image or a video.

Devices & Technology

AR-glasses
AR-glasses are glasses that can see the physical world, but virtual objects and data can be added to the lenses so that they appear to be in the physical environment. Examples: Microsoft Hololens 1 & 2, Magic Leap One.

Base stations
Base stations are external stations that enable some VR-headsets to track their position and orientation. Base stations are used as reference points in space for the VR-headsets and they are laser-based.

CAVE = Cave Automatic Virtual Environment
CAVE is an immersive environment produced by projectors in a cube-shaped space. Motion capture system tracks the user’s movements and position in real time and the user can see objects in the space with their 3D-glasses. 3D sound is also produced into the CAVE. CAVE was invented in the Electronic Visualization Laboratory in the University of Illinois in 1992.

Eye tracking
Eye tracking is following users’ gaze with devices and programs. Eye tracking can be used to analyse where users pay attention or for example to control with gaze in virtual reality.

FoV = Field of View
Field of view is reported as degrees in VR-headsets. The higher the degree is, the wider the field of view is for the user. The nearer the field of view is compared to the human field of view, the more realistic the virtual reality experience is for the user.

Hand tracking
Hand tracking is tracking of the user’s hand position and movement with devices and programs. In virtual reality, hand tracking can replace the use of controllers.

Haptics, haptic perception
Haptics is a perception method that is based on feeling a three dimensional object by touch of the skin and movement of hands or other body elements.

VR-controllers
VR-controllers enable interactivity with virtual reality. Usually controllers are for controlling the hands of the user in virtual reality. Controllers have many buttons that can be used to for example grab objects, push buttons or teleport in virtual reality. Manufacturers have different designs for controllers.

VR-headset (syn. HMD, head mounted display, VR-device)
VR-headset is a head mounted device that allows the user to see the computer-generated three-dimensional virtual reality. VR-headsets usually include two stereoscopic lenses, sensors to track movement and a sound output. With a VR-headset the user can be immersed in virtual reality. Examples: Oculus Rift & Rift S, HTC Vive, Vive Pro, Vive Cosmos & Vive Focus, HP Reverb & Reverb G2, Valve Index, Varjo VR-series.

Wireless / standalone VR-headset
Wireless VR-headsets do not need an external computer to work, the computing is done within the headset. Most VR-headsets need a powerful external computer to use applications, thus they are connected to the computer with a wire that can disturb movement. Examples: Oculus Go, Oculus Quest 1 & 2, Pico Neo 3.

360-camera
360-camera can be used to take 360-images or -videos.

6DoF = 6 Degrees of Freedom
Six degrees of freedom in VR-headsets imply that it can track movement in three axes: up-down, left-right and forward-backward, Thus, the user can move freely with their body to all directions. In older VR-headsets with three degrees of freedom (3DoF) the user can only move their head to look in different directions.

Virtual Implementation

Application (syn. app)
Application is a computer program that has been made to simplify or implement some actions from the perspective of the end user. Applications are downloaded for example to computers, smartphones, tablets and wireless VR headsets.

Game engine
Game engine is a visual computer software that includes vital parts of game development like rendering, collision physics, animation, artificial intelligence and sound. Examples of commercial game engines are Unity, Unreal Engine and Source.

UI = User interface
User interface is a set of buttons, switches, programs and so on that are used to control a machine or a computer. It is an interface between the interaction of a human and a computer. GUI or graphical user interface includes visual control panels for using different programs with a computer.

Mocap = motion capture
Motion capture is a technique in which physical movement of the object is recorded with sensors and transformed into a digital form.

Volcap = volumetric capture
Volumetric capture is a technique in which the three dimensional form of the object and its movement is fully captured with sensors and transformed into a digital form.

WebVR
WebVR is a JavaScript application programming interface that enables virtual reality in web browsers.

3D-graphics
3D-graphics is three dimensional graphics made with a computer program.

3D-modeling = three dimensional modeling
3D-modeling is three dimensional planning with a computer program.

While putting together this xr glossary, we studied the following virtual reality themed glossaries that included other terms as well:

EDUXR-sanasto

Muukkonen & Putkonen, 2020. Virtuaalimaailmassa tapahtuu: Käsikirja VR-tapahtuman tuotantoon

Premode: Mikä ihmeen pelillistäminen? Virtuaalisanasto ja lyhenteet

The VR Glossary -website