Force feedback

Overview
"The availability of force feedback is a powerful addition to a virtual environment. By sensing the position of the fingers relative to a virtual object, such as a simulated rubber ball, the system can introduce force cues as the user closes his or her hand around the virtual object. With suitable sensors and actuators, the object can be made to feel stiff or spongy by systematically manipulating the characteristics of the force cues as a function of the position and motion of the fingers relative to the position of the object."