A. A Virtual Reality Head Mounted Display (HMD)
- One or two high-resolution displays like the ones used in smartphones. Two displays allow for a higher resolution per eye.
- A pair of lenses that are used to magnify the image on-screen to appear as if the user is in it.
- A gyroscope, magnetometer, and accelerometer, which detects head rotation as you turn your head in the virtual world.
- Refresh Rate(Hz) – refers to how many times in a second the screen updates. The higher the better as it makes a smoother experience and can help prevent motion sickness.
- Latency – refers to the time between your input (head movement) to the output (screen display). While this is influenced by a mixture of technologies and not just the headset, it is an important factor that will determine the immersion of the experience and prevent motion sickness.
- Stereoscopic Images - Virtual reality content is often displayed in a dual image format to simulate the left and right eye. This is done to simulate depth – like 3D movies to give the objects you are looking at on-screen more of a physical presence.
- FOV – field of view. A higher field of view results in a more immersive experience like reality.
- Distortion – With magnification of the image comes distortion along the curvature of the lenses. Software is used to correct distortion caused by lenses.
- Mobile HMDs – using smartphones to power the VR experience. Normally with a separate case and lenses. This is the most accessible of all VR technologies given the ease of use and general cost.
- Tethered HMDs – powered by powerful machines such as PCs and consoles. Takes advantage of high-performance graphics and processing. It offers experiences that are far superior and immersive but require a high powered machine to operate.
- Augmented Reality HMDs – Unlike VR HMDs which are entirely closed off, AR HMDs allow the users to see the real world through a front-facing capture device while overlaying a digital interface over it – bringing virtual elements into the real world.
- Mixed Reality HMDs – HMDs that combine VR and AR experiences.
B. Controllers
- Standard Gamepads: Like controllers used for the PlayStation or Xbox, gamepads can be used to interact with virtual reality. They allow control for movement and interaction in a format that most gamers are familiar with.
- Motion Controllers: Arguably the most favored form of VR controllers. They usually come in the form of twin controllers (one for each hand) and offer interactive buttons and input, while being able to track the physical movement of a user’s hands in all directions, allowing for an enhanced feeling of physical presence in the game.
- Motion controllers can also come in the form of gloves or cameras that track the movement of your hands.
- Locomotive Controllers: Locomotive controllers help simulate movement in the virtual world. While standard controllers and motion controllers can do this, locomotive controllers actually simulate walking/running. Locomotive controllers can come in the form of omnidirectional treadmills –treadmills that allow the user to walk endlessly in any direction they want, or chairs that allow control for movement by leaning in different directions to name a few
- Other Technologies: There are other controller technologies being experimented with such as eye-tracking – allowing users to interact with objects just by looking at them, or haptic feedback controllers, which allow simulation of touch in the virtual world. The VR industry is new and still growing, so this list should continue to grow as more companies innovate around the technology.
C. Tracking Cameras
*While tracking cameras help improve immersion for VR they are not always necessary.
Tracking cameras help track the user’s position in the virtual space. This can range from leaning in different directions with your head to being able to walk around in a limited space.
- Positional Tracking Cameras: Most Virtual Reality HMDs come packaged with basic positional tracking cameras.
These cameras are placed in front of the user and allow the user to lean in all directions in combination with basic movement (VR controllers) and head rotation (HMD) providing enhanced sense of presence and immersion. This allows you to lean forward to examine objects more closely and makes for a more immersive experience by adding depth.
- Room-Scale Tracking Cameras: These cameras are mounted above users in a fixed space, typically a few square meters large.
In addition to tracking leaning in all directions like basic positional tracking cameras, they also are able to track movement within the entire space, allowing users to walk around in the VR world without extra controller input.
This, combined with motion controllers, represents the most natural way of interacting with virtual worlds to date – with the controllers tracking hand movement and the room-scale tracking cameras translating your physical movement in real life to virtual reality. It provides for the ultimate sense of immersion and presence.
D. Virtual Reality Enabled Content
Content (entertainment and games) need to be created with Virtual Reality in mind in order to make full use of the various technologies outlined above.
Factors required to make content VR enabled: - Compatibility with Display technologies: VR content must be displayed in stereoscopic format. This is one of the requirements for content to be considered virtual reality content.
- Compatibility with Controllers and Positional tracking technology: The content must be developed to work with the various controllers highlighted above.
- Availability of Emulators: There are emulators available that make standard content today VR compatible. These emulators have to be supported by the VR platform you decide to use. Content will also need to be actively supported by the emulator.
Designed for VR vs VR-Ready Content
There are two main categories of VR content available today. Designed for VR and VR-Ready Content
- Designed for VR: Created from the ground up to provide users with the most immersive VR experiences possible. Optimized for motion controller and HMD technology.
- VR-Ready Content: VR-Ready content can be existing content that has been made compatible with VR technology. While still offering an immersive experience than standard formats they might not be as well optimized in terms of game and level design.
