This paper describes a new virtual reality system designed to be small enough to be totally portable. It is a semiimmersive interaction system based on a movable stereoscopic projection screen with a tracking system to capture the movement of the screen with respect to the virtual model. The system can be used for cooperative inspection of very complex computer-aided design environments, allowing very simple interaction among users and designers at distant locations. r 2003 Elsevier Ltd. All rights reserved.