Abstract: A computer model of a virtual environment is continuously modified by input from various participants. The virtual environment is displayed to the participants using sensory displays such as head-mounted visual and auditory displays which travel with the wearer and track the position and orientation of the wearer's head in space. Participants can look at each other within the virtual environment and see virtual body images of the other participants in a manner similar to the way that people in a physical environment see each other. Each participant can also look at his or her own virtual body in exactly the same manner that a person in a physical environment can look at his or her own real body. The participants may work on a common task together and view the results of each other's actions.

Abstract: A method of electronically aligning a first sensor having two substantially nonparallel sense axes producing first and second output signals and carried by a garment so as to be positioned proximate to a joint's first axis of movement with a second sensor having two substantially nonparallel sense axes producing third and fourth output signals and carried by the garment so as to be positioned proximate to the joint's second axis of movement, comprises the steps of: reading values for the third and fourth output signals at two points while the joint is moved substantially along only the joint's first axis; electronically combining the third and fourth signals so that the combined output is constant; reading values for the first and second output signals at two points while the joint is being moved substantially along only the joint's second axis; and electronically combining the first and second signals so that the combined output is constant.

Abstract: A radiation source directs radiation toward a radiation sensor in such a way that the intensity of radiation sensed by the radiation sensor alternates in a periodic manner as the radiation source moves radially relative to the radiation sensor. The radiation sensor generates either a "1" or a "0" depending upon whether the intensity of the radiation sensed by the radiation sensor is above or below a particular reference value. Thus, the angular position of the radiation source relative to the radiation sensor is indicated by an alternating series of "1"s and "0"s. A multi-bit binary value which indicates the absolute position of the radiation source relative to the radiation sensor can be generated. In this case, a band of radiation is directed toward the radiation sensor. The radiation band is separated into a plurality of portions, the intensity of each successive portion being twice the frequency of the preceding portion. Each portion of the radiation band impinges upon a corresponding sensor.