ABSTRACT
Virtual reality, also known as virtual environments or virtual worlds, is a new paradigm in computerhuman interaction, in which three-dimensional computer-generated worlds, called virtual environments, are created which have the effect of containing objects that have their own location in three-dimensional space. The user’s perception of this computer-generated world is as similar to the perception of the real world as the technology will allow, providing appropriate depth and three-dimensional structure cues. User perception in virtual reality can be via a variety of senses, including sight, sound, touch, and force. Virtual environments are often, but not necessarily, immersive, providing the effect of surrounding the user with virtual objects. Objects in the virtual environment are often autonomous and/or interactive. The user interacts with the virtual environment using several interaction techniques, with a stress on direct manipulation in three-dimensional space via interface metaphors from the real world, such as grab and point, where appropriate. In order to create the effect of interactive three-dimensional objects, the virtual environment must be processed and presented at a near-real-time rate of 10 frames/s or greater. The threedimensional perception and interaction in the virtual environment, its real-world-like interface, and its inherently near-real-time response property make virtual reality a natural interface for three-dimensional applications, including training for real-world tasks.
