This paper explores the nature of creative composition particularly as it applies to dance, and describes the development of interactive computer based tools to assist the composer. The hierarchical nature of the composition process calls for an interface which allows the composer the flexibility to move back and forth between alternate views and conceptual levels of abstraction.COMPOSE, an interactive system for the composition of dance has been implemented on Silicon Graphics and Apple workstations. The user visually composes in space and in time using menus of postures and sequences. Paths can be edited and an animation of the dance composition allows the final result to be evaluated.

New single- and multiprocessor models for ray tracing are presented. Important features are (1) the use of custom VLSI building blocks, (2) the use of a modified hierarchical data-structure-based ray tracing algorithm with three disjoint data sets, and (3) scene access through adaptive information broadcasting. A modular design is presented that permits incremental performance enhancement up to two orders of magnitude over conventional minicomputers or workstations. Ray tracing is a surprisingly good application for a shared bus architecture because of the computational complexity of intersecting light rays with graphics objects.