Volume 3, Number 2, Spring 2003 (Software Review)

�Quick-Draw� an AutoLISP-Based Software
Application to Increase HVAC System
Design Productivity

Robert W. Hewitt, Jr.
University of Memphis
Memphis, TN 38152-3380


The ability of a company to respond quickly and accurately to customer needs is essential to survival in the competitive atmosphere of the Heating, Ventilating, and Air-Conditioning (HVAC) industry.Through its AutoLISP programming interface, AutoCAD allows manufacturers to create specialized applications that reduce the drudgery of repeatedly designing similar systems, and dramatically increase productivity. This article will discuss one company�s use of AutoLISP-based software to reduce the time necessary to design positive-pressure commercial venting systems.

AutoLISP is a specialized subset of the LISP (List Processing) programming language.It has been available as a standard feature in AutoCAD almost since its inception.The syntax of AutoLISP is extremely simple, and does not have to be compiled before it is run.American Metal Products, located in Olive Branch, Mississippi has taken advantage of the language�s flexibility and seamless integration with AutoCAD and Mechanical Desktop to reduce the time required to generate drawings of complex venting systems.

Known as �Quick-Draw,� the AutoLISP-based application used by American Metal Products allows an engineer to draw a 3-D �skeleton� of a venting system, and then �flesh� it out with custom generated solid models of venting components such as pipes, elbows, tees, and other fittings (Figure 1).The program then generates standard orthographic views of the system, and creates a complete bill of materials (BOM) for the system (Figure 2).

The speed of the software has made it possible for a customer to receive a quotation for a complicated system within days or sometimes even hours.�Quick-Draw� also creates a BOM file that is read by another custom-developed application that generates a complete quotation report.The BOM file is also used when an order is received to generate bar-code labels that drive the manufacturing process.

Before the implementation of the AutoLISP-based �Quick-Draw� application, producing system drawings was a slow, labor-intensive task.This application has improved not only the time it takes to generate system drawings, it has also increased the accuracy of quotations and production by eliminating manual data-entry processes and producing bar-code labels to accurately control the manufacturing and shipping functions.

Last Updated on 8/29/2005