Virtual Reality, sometimes referred to as immersive multimedia, is a computer-simulated environment that can simulate physical presence in places in the real world or imagined worlds. Virtual reality can recreate sensory experiences, which include virtual taste, sight, smell, sound, touch, etc. Most current virtual reality environments are primarily empirical experiences, displayed either on a computer screen or with special stereoscopic displays, and some regulated simulations include additional sensory information and emphasise real sound through speakers or headphones targeted towards witnesses. Some advanced, haptic systems now include tactile information, generally known as force feedback in medical, gaming and military applications. Furthermore, virtual reality covers remote communication environments which provide virtual presence of users with the concepts of telepresence and telexistence or a virtual artifact either through the use of standard input devices such as a keyboard and mouse, or through multimodal devices such as a wired glove, the Polhemus, and omnidirectional treadmills.