Hidden Lines using the EXCELL Method

Abstract

The Extendible cell (EXCELL) method provides a data structure for efficient coordinate based access. It stores geometric data into computer storage blocks corresponding to disjoint variable sized rectangular cells accessible by an address calculation type directory. Two efficient hidden line algorithms utilizing an EXCELL structure are presented, both of which perform satisfactorily even if central memory is small compared to the total amount of data. The computation time is approximately proportional to the amount of input. An important aspect of the method is that the programs are contained within a "standard" general purpose graphics system.