An algorithm to display three-dimensional objects

Abstract

An algorithm is described for displaying three-dimensional objects with hidden parts removed. An object can be regarded as being made up of a number of planes (e.g, a cube is formed by six square planes) and therefore the whole picture can be visualized as only a collection of planes. To complete the picture, it is necessary to remove those parts of a plane that are covered by the other planes as viewed in a certain direction, and this can be achieved by considering only two of-the planes at any one time. This paper describes a FORTRAN program for producing an isometric view of an arbitrary collection of objects as viewed in any given direction. A perspective view of the picture is also possible by using a suitable projection, and is described in a later section. The program is implemented by a PDP 11 computer using 28k and the graphic terminal used is Tetronik 4010.