This new dynamic form of graphical representation, in its most often applied form, is built on the use of pixels. A pixel is a point of light on a raster display. By varying the intensity of red, green, and blue in each of a large matrix of pixels, full color images are produced. Making full color images on a screen takes a lot of processing power and if those images are intended to change in real-time this increases the requirements on the processor immensely. However, this is what we want to do to be able to fully model our world.
Virtual reality goes beyond just the visual display, however.
The objective of virtual reality is to immerse the user in an alternate world that he or she can believe to be real. One of the drawbacks of Sensorama was that it was limited to a motorcycle ride through Manhatten. Since that time, many other tools have been developed that can implement more general environments. For most of the eighties and into the nineties, virtual reality and real-time graphics applications have been implemented on platforms specifically developed for the task. Silicon Graphic has been the primary computer platform for real-time graphics systems, because they have designed hardware specific to the needs to 3D rendering and placed that hardware in the boxes they build.