Tactile, spatial interfaces for computer-aided design: superimposing physical media and computation

Computer-aided design (CAD) systems have become invaluable in three-dimensional creative design fields such as architecture and landscape architecture. However, these digital tools have not replaced the use of physical tools and materials as envisioned by the early developers of CAD. Instead, most designers have added digital media to their suite of physical media, gaining the benefits of both realms and using each where it is most advantageous. Given current CAD systems and how they are being used, two significant problems are apparent. First, the side-by-side physical/digital work environment has resulted in the need to frequently digitize and print in order to switch between physical and digital representations. This process is often time-consuming, costly, and frustrating. Second and more fundamental, the standard graphical user interface (GUI), although appropriate to some tasks, is restrictive as the only interface to CAD, because it lacks tactile and spatial qualities. Interacting with physical media such as paper, cardboard, and clay is a multisensory, spatial experience. Interacting in a GUI may be visual, but our other senses and spatial abilities remain underutilized. Recent interface design research includes embedding or augmenting physical artifacts with computation as one remedy to the limitations of the GUI. This dissertation investigates whether superimposing physical and digital media to create new interfaces for CAD has merit. Findings are presented from experiments performed with Illuminating Clay, a prototype interface that superimposes modeling clay and topographic analysis. The objective was to discover whether these new kinds of interfaces could successfully combine the cognitive, motor, and emotional advantages of physical media with the capabilities of computation. Findings indicate that Illuminating Clay can indeed supplement a designer's eyeball analysis with more-accurate feedback while retaining the tactile and spatial advantages of working with a physical material. Salient issues pertaining to the design of tangible, and augmented-reality user interfaces were raised by these experiments: what the appropriate scale limitations should be, what the appropriate type of feedback is from computation, and whether real-time feedback is necessary. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)