orignal article posted here: https://whatis.techtarget.com/definition/360-degree-VR-360-degree-virtual-reality
360-degree VR (360-degree virtual reality) is an audiovisual simulation of an altered, augmented or substituted environment that surrounds the user, allowing them to look around them in all directions, just as they can in real life.
360-degree VR can be used for many purposes other than entertainment. The virtual reality technology can be used in most kinds of training that involve a physical environment, including pilot and driver training (as well as actual piloting or driving), surgery, and undersea and space exploration via remote-control robots.
There are a number of types of 360-degree VR, including live and previously captured video or real-time, real-time rendered 3D games, and pre-rendered computer graphics imagery (CGI).
Events captured to video from the real world require a number of cameras to record the surrounding environment. While this kind of VR can be rigged by multiple individuals using numerous like cameras, it takes two cameras per view to create depth and a lot of tricky post-processing and editing. 360-degree VR products include NextVR's $18,000, six thousand pixel, six-camera purpose-made device, which records three views from a center point. The 2015 MTV video music awards were broadcast through that method.
CGI-based VR games and computer hardware have been capable of supporting VR for years and visual quality is always increasing, to the point that the need to pre-render graphics is questionable. This is an important improvement because having to pre-render graphics limits the interactivity of the simulated world. Nevertheless, for the highest visual fidelity and realistic lighting, the same computer hardware can produce a better, more complex image when given more time to work on a frame of animation. However, to produce pre-rendered CGI, the time required is multiplied by the number of views required to render a scene.
Although the hardware to create 360-degree VR has existed for years, the technology for the user experience hasn’t until recently. A decent user experience can be created using multiple projectors but this is an expensive, bulky, power hungry and hot way to experience VR. Currently available 360-degree VR consumer systems include Oculus Rift, Morpheus, HoloLens and Vive & Gear.