The Spacepad magnetic tracking system used with the ImmersaDesk is a plug-in PC ISA bus system and has the following components:

• Antenna, which consists of three wire loops mounted on plywood and configured on a flat plane that is inclined at 35 degrees, and held in place above the I-Desk. During shipping the antenna piece is removed and flipped over the screen to protect it.

• The transmitter and the receivers are integrated into the PC board.

• 2 receiving antennae - one attached to the glasses and one to the wand. (If more receiving antennae are used, more receiver cards must be added to the PC).

• The Spacepad PC card communicates with the SGI.