Virtual reality (VR) is a synthetic environment created with a computer and presented to the user in such a way that the user accepts and belief that the environment is real. Virtual reality is a two-word terminology used in computer science in which Virtual” means near and Reality” means as a human being what we experience in our daily life is a reality. So we can say that virtual reality is an articial computer-generated environment where the user interacts with virtual objects that serve similar or near to the real world. According to Jaron Lanier who 1st introduced the VR in the year, 1986 \We are speaking about a technology that uses computerized clothing to synthesize shared reality. It recreates our relationship with the physical world in a new plane, no more, no less. It doesn’t afect the subjective world; it doesn’t have anything to do directly with whats going on inside your brain. It only has to do with what your sense organs perceive”.
Virtual reality according to Howard Rheingold is a 3D environment generated with a computer in which the users feel their presence. In the virtual environment, the user is capable to navigate freely from one location to another, examine it from different views, to get in touch with this Virtual environment, to know it and wield it.
After that different researchers defined VR in different ways. For example, according to Aukstakalnis et al. human use VR as a tool for visualization, manipulation, and interaction with computers and other complex data. VR is an advanced interface between human and computer which provides a realistic environment for their interaction. Davies dened VR as a method to use computers for modeling real or non-real 3D environments and permits users to interact with these environments in a simple and natural manner. According to Loftin, VR is a technology that displays information in multi-modal form along with real-time interaction with information in 3D space and allows occupation, navigation, and manipulation in the virtual environment. VR is a scientic domain that exploits computer and behavioral interfaces,
(1) to simulate in a virtual world
(2) the behavior of 3D entities, that interact in real time
(3) together and with one or more users in pseudo-natural immersion
(4) through sensorimotor channels.
Virtual Environment (VE) can be dened as the representation of real or non-real information in 3D space which allows real-time interaction. VE can be divided on the basis of the degree of immersion as Non-Immersive Virtual Environment (NIVE), Semi-Immersive Virtual Environment (SIVE), and Fully-Immersive Virtual Environment.