mean a VR capability whereby a participant perceives himself/herself, from a first-person point of view, to be inside the aircraft geometry, "wearing" a graphical human body whose positions and movements closely mimic his/her own. Position/orientation sensors on the participant's limbs, torso, and head provide the necessary information to the computer, enabling it to draw the graphical body (sometimes called an "avatar") in a corresponding position. Real-time collision detection software informs the participant if he/she has bumped into an obstacle. Someday, haptic feedback systems may enable the user actually to feel such a collision. In the meantime, we provide sound cues and make the object change color to notify the user of the collision.

The fundamental problem we face in trying to use aircraft CAD geometry as our virtual environment is one of scale. CAD geometry is orders of magnitude more complex than the scenes usually portrayed in VR systems. Any subset of interest to the aircraft engineers is likely to contain millions of polygons worth of geometric data, and rendering such data sets in stereo at 25 to 30 frames/second is a daunting challenge. Providing on-the-fly collision detection among such complex geometry is equally daunting. Our approach probably could best be characterized as "use every trick in the book," because all are probably necessary to handle geometry of this scale. The algorithmic techniques we are trying to combine include

• parallel rendering algorithms,
• upstream occlusion culling,
• object simplification and level-of-detail control, and
• substitution of texture maps for geometry.

Independently of the VR project, we are working on another technology involving a VR-style head position/orientation tracker; a see-through head-mounted display; and a belt-mounted, battery-operated computer. This combination makes up the hardware platform for our Augmented Reality (AR) system. Since the display is see-through, the AR system can be used to superimpose computer graphics on the surface of a real object the user is viewing. Because we employ a position/orientation tracking system, the computer can change the display whenever the user moves his/her head, making the graphics appear to be fixed on specific coordinates of the real object. Our goal is to have people who perform touch labor manufacturing tasks use this technology. At every step of a manufacturing or assembly procedure, the diagrams or text a worker needs to perform that step quickly and accurately will appear to him/her as if they were painted on the surface of the workpiece.

The critical technical issue for AR is the head position/orientation tracker. Current commercially available trackers are not adequate for factory use.

Front Matter (R1-R10)

Design Research (1-2)

Designing Vehicles in Changing Times (3-8)

Development of Performance-Based Seismic Design Procedures (9-12)

Information in the Design Process (13-16)

Product Modularity: A Key Concept in Life-Cycle Design (17-22)

Visualization for Design and Display (23-24)

Visualizing Aircraft Aerodynamic Design (25-28)

Virtual Reality and Augmented Reality in Aircraft Design and Manufacturing (29-31)

The Frontiers of Virtual reality Applied to High Performance Computing and Communications (32-36)

Digitizing the Shape and Apperance of Three-Dimensional Objects (37-46)

Microelectromechanical Systems (47-56)

Fabrication Technology and the Challenges of Large-Scale Production (57-62)

Frontiers in MEMS Design (63-66)

Large-Market Applications of MEMS (67-72)

Innovations in Materials and Processes (73-82)

Silicone Satellites (83-85)

Novel Ceramic Ferroelectric Composites (86-90)

Co-Continuous Composite Materials from Net-Shape Displacement (91-94)

Dinner Speech (95-96)

Institutional Cultures and Individual Careers (97-106)

Contributors (107-114)

Program (115-116)

Participants (117-123)