Papers
	CHI 99 Conference on Human Factors in Computing Systems Pittsburgh, Pennsylvania USA 15-20 May 1999 1999 AC 101kb Urp: A Luminous-Tangible Workbench for Urban Planning and Design John Underkoffler and Hiroshi Ishii Tangible Media Group MIT Media Laboratory 20 Ames Street, Cambridge, MA 02139 USA {jh, ishii}@media.mit.edu ABSTRACT We introduce a system for urban planning – called Urp – that integrates functions addressing a broad range of the field’s concerns into a single, physically based workbench setting. The I/O Bulb infrastructure on which the application is based allows physical architectural models placed on an ordinary table surface to cast shadows accurate for arbitrary times of day; to throw reflections off glass facade surfaces; to affect a real time and visually coincident simulation of pedestrian level windflow; and so on. We then use comparisons among Urp and several earlier I/O Bulb applications as the basis for an understanding of luminous-tangible interactions, which result whenever an interface distributes meaning and functionality between physical objects and visual information projectively coupled to those objects. Finally, we briefly discuss two issues common to all such systems, offering them as informal thought-tools for the design and analysis of luminous-tangible interfaces.