The controlling program sets up the sounds in the virtual environment and monitors the user's actions. Sensors check the user's head and control wand position and orientation, as well as whether a movement button (forward or backward) or selection button has been pressed. At regular intervals, the user data are processed. If the user moves to a new group of sounds or presses the selection button, the closest objects are sounded and change color.
Nearly 80 samples, representing 54 different instruments, were selected from Digidesign's SampleCell CD-ROM. They are arranged in a two-dimensional tree (though the user can move in three dimensions). They appear as about twenty groups of instruments, with lines linking each instrument entity to its child and parent nodes, spread across a plane in front of the user. (The structure of the layout can be changed by altering the database; it is not necessary to change the controlling program.)
