A hidden line algorithm for halftone picture representation

In exploring applications in computer graphics, one finds quickly that the representation of three dimensional objects in picture form is both a desirable and necessary capability. Applications dealing with any form of spatial design or with visual environment simulation need the ability to represent objects and their relationships to each other in three dimensional space. This capability is enhanced if the variety and complexity of pictures is great and if the pictures can be presented with a wide range of intensities or in color if possible. Other features that are desirable are the abilities to have more than one light source and, if possible, to consider secondary illumination on the objects viewed.