A computer generated environment where users interact using immersive input and output devices. VR can simulate a real environment or a fictional one. Many computer games can be classsifed as a type of VR, such as Quake II and flight simulators. A VR experience can be enhanced by adding the sense of touch to a VR system. The PHANToM allows 3d input in a VR world while providing force feedback response. Stereoscopic vision can also enhance VR