Non-local blending of boundary models

The paper describes varieties of blending in kernel boundary modellers emphasizing topology, algorithms and program structure rather than geometry and using examples drawn from the ACIS modeller. It illustrates some of the many configurations that can occur when blends spread on to faces distant from the original implicitly blended edges and vertices. From a systems standpoint, a staged evaluation of blends is shown to have advantages in the use of existing Boolean code to perform much of the work. Lastly the paper explains how object-oriented methods can ease the addition of new categories of blend by applications built on a kernel modeller. Copyright (C) 1996 Elsevier Science Ltd