Interactive Graphics in Data Processing: Modeling in three dimensions
by A. Appel
Discussed are two computer programs for generating and realistically plotting any view of a three-dimensional object from the same object description, thereby simulating the viewpoints of a person moving around the object. Although the programs have been implementedon an experimental basisfor digital plotting, the use of the underlying concepts for graphic display is contemplated. Involved in the SIGHT program are approaches to some of the most difficult problems in three-dimensional graphicsthe hidden-line problem, approximating curved solids by polyhedra, and simulating degrees of surface transparency. The description of the program LEGER emphasizes the design of data storage for the object description. This scheme allows the use of the same data for generating all views of the object. The data structure can be modified to adjust the dimensions of the scene and the relative orientations of the component parts.