A Utilitarian Approach to CAD

The benefits of using and writing software utilities are appreciated by most software engineers. However, many Computer-Aided Design (CAD) systems do not take full advantage of this technology. This could be because good utilities do not exist, because CAD developers are not aware of existing utilities, or because developers do not know what features to include and leave out when they are writing their own utilities. As with much of computer science, the art of effectively using and writing software utilities has remained just that: an art. This paper discusses the desirable features of good software utilities for CAD and describes techniques that encourage effective use of existing utilities as well as the specification and implementation of new ones. Throughout the paper, experiences from a four year development effort in Designer's Workbench (DWB) [1] are used as examples (both good and bad).