Haloed Line Effect for Casting Shadows
Original Publication Date: 1980-May-01
Included in the Prior Art Database: 2005-Feb-13
The haloed line effect, previously described in the IBM Technical Disclosure Bulletin 21, 1715-6 (September 1978), can be used to determine the approximate shape of shadows cast by a remote light source. In the use of the haloed line effect to enhance the illusion of depth in a computer-generated picture of a three-dimensional scene, lines that passed in front of other lines would cause a gap in the more remote line. This is illustrated in Fig. 1. To cast shadows, instead of causing a gap, the lines could be broken into two types of lines: illuminated and shaded.