“A method of interactive visualization of CAD surface models on a color video display” by Atherton

To introduce rendered surface display technology into the production design environment, many CAD operations envision a single color video display device for download processing of selected model pictures. Creation of a single image from a typical industrial CAD model involving a large number of higher order curved surfaces will normally require a minimum of several minutes’ delay for data acquisition and visible surface computation. This paper describes a method that extends the visible surface operation to give the designer an interactive tool with which he can more effectively comprehend model composition. Instead of defining data for a single image, an intermediate three-dimensional structured file is created. A tailored display program manipulates the structured data file allowing a user to interactively create surface rendered images. Program capabilities include: • Section and cutaway viewing • Selected surface color, transparency, or translucency • Shadows projected from desired light-source locations Changing or combining any of these facilities requires only seconds for a new image to be created.

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