An electromagnetic position and orientation measurement system has been developed that constantly measures the three-dimensional coordinates of a moving sensor in relation to a fixed source.The system employs two modules, each consisting of three small coils forming an orthogonal triad. One module acts as a fixed source to generate an electromagnetic field, while the other module acts as a movable sensor to sample the field. An electronics unit performs all computing and interfacing functions.As a Digitizer, the system is used to input real world, three-dimensional objects to a database, and to input the coordinates of engineering models to a computer for generation of isometric drawings and material takeoff lists. In its Piping System configuration, the unit eliminates the need for manual measurement of model coordinates. By touching a point to be measured with the stylus, coordinate data points are automatically transferred to a host or a commercially available microcomputer for storage.