The virtual environments created through computer graphics are new communications media.
They are generally experienced through head-coupled, virtual image, stereoscopic displays that can synthesize a coordinated multisensory presentation of a synthetic environment.
A well-designed human computer interface gives the user an efficient, effortless flow of information between the device and its operator.
When users are given sufficient control over the pattern of this interaction, they themselves can evolve efficient interaction strategies that optimize their communications to the machine
Virtualization may be defined as the process by which a viewer interprets patterned sensory impressions to represent objects in an environment other than that from which the impressions physically originate
A classical example would be that of a virtual image as defined in geometrical optics
A viewer of such an image sees the rays emanating from it as if they originated from a virtual point rather than from their actual location
Three levels of virtualization may be distinguished: virtual space, virtual image, and virtual environments.
These levels represent points on a design continuum of virtualization as synthesized sensory stimuli more closely acquire the sensory and motor characteristics of a real environment.