Computer Assisted Assembly and Rendering of Solids.

The objective of the paper is to describe a technique that produces shaded renderings of solids and to describe an assembly procedure which may be used to assemble representations of 3-D objects in such a way that they can be photographically rendered. The algorithm that is used to produce photographic renderings may be subdivided into two parts -- 1 the visible surface procedure that determines which surfaces are visible and which are invisible and retains the description of only the visible surfaces, and 2 the shader which varies the tonal gradation on all visible surfaces. The assembly procedure is a tool that allows a user to form, manipulate and photographically render 3-D objects. A set of primitive structures described by planar triangles are used as the 3-D object building-set. Both the rendering and assembly procedures are presently operational software programs written in a combination of Fortran V and UNIVAC 1108 Assembly Language. Author