CAD Manager's Newsletter (#205)

7 Oct, 2008

Programming Topics, Part 3: AutoLISP

More tips on using AutoLISP codes to customize and control your CAD operations.

In the previous edition of the CAD Manager's Newsletter, I continued my series on programming methodologies by exploring some AutoLISP concepts that are useful for CAD managers. I've been bowled over with e-mail responses to this series, many asking for more AutoLISP.

In this installment, I'll show you how to use the UNDEFINE and DEFUN methods I've already discussed to redefine existing AutoCAD (or AutoCAD vertical products) commands to your liking. First, I'll set up an example problem, and then I'll show you how to make it happen. Here goes.

The Problem Statement
A CAD manager wants to redefine the way that users save files. To this end, she wants to disable the SAVEAS command so that users can't change the name of files. Further, she wants to make sure that users always purge the dead blocks out of their drawings every time they save. Finally, she wants to add useful new commands into the file.

Here are some things the CAD manager needs to know:

  • SAVEAS. The actual command in AutoCAD that allows users to rename an existing drawing.
  • QSAVE. The command that allows users to save drawing changes without changing the name of the file. In the case of a new drawing, the QSAVE command will prompt for the file name the first time, but not afterwards.
  • -PURGE. The command line version of the PURGE command that allows users to automate the purging process.
  • ACADDOC.LSP. The LISP file, where we'll create the programming code, must be located in a support folder (per the Options command).

Read more »


:: CAD Manager’s Toolbox: Back Up Your Hard Drive

You never know when you might lose your data — or even your computer.

I was recently on a trip to London where an associate misplaced a laptop and feared it had been stolen. As each hour passed without the machine being located, the mood grew more dour as the thought of the expense and the hassle of replacing all that data became an all-too-real possibility. And even though the laptop was backed up every week, the prospect of losing that last week of work made the situation seem even worse. Luckily, the laptop turned up later that day. But the lesson learned, with respect to data backup, was reinforced on both of us -- especially with regard to laptop machines.

I've been using an online backup tool called Carbonite for the past four months, and I've been very impressed with it.

The strength of Carbonite (see below) is that you simply tell it what you want backed up (I back up my entire C drive), and then Carbonite waits for your machine to go idle (essentially, when your screen saver kicks in). As soon as your machine becomes idle, Carbonite starts backing up everything that has changed to the company's secure data servers automatically, assuming you have an active Internet connection. Read more »

Got a cool tip I should know about? Send it to me at If I used your tip in the newsletter, you'll receive a cool Cadalyst prize!

:: Resources

Check Out the CAD Tips Site
"Hot Tip Harry's" code for October is online and ready to download. Be sure to read Harry's October column to learn more about this month's batch. Then head over to Cadalyst's new CAD Tips site to download your favorites. The new additions are listed under Recently Posted CAD Tips, or search for specific tips by tip number or keyword. Registered users also can review, post comments, and upload revised versions of code! Congratulations to Pedro Ferreira, who developed this month's top tip, Annotate Profile Data, a wonderful productivity tool for civil engineers.

Online Autodesk Student Community Gets Facelift
The enhanced Autodesk Student Engineering and Design Community offers new features and benefits including: community networking, career center, profile sharing, RSS news feeds, and blogging capabilities. The company also launched the Autodesk Student Engineering and Design Community Facebook page to connect users of Facebook and CAD software.

:: Events

Building Geospatial Business Systems Seminar
October 8, 2008
Brussels, Belgium
At this seminar, Oracle and ERDAS executives will discuss strategy, sharing perspectives on enterprise-business solutions that integrate geospatial information. Read more »

Build Boston 2008
November 18-20, 2008
Boston, Massachusetts
This three-day event, sponsored by the Boston Society of Architects, is a regional tradeshow and convention for the design and construction community. More than 350 exhibits and 225 workshops will be featured. Read more »

2009 3D Collaboration and Interoperability Conference
May 17-20, 2009
Estes Park, Colorado
Longview Advisors invite anyone interested in improving the efficiency of their global product design, development and manufacturing operation, to engage in a series of presentations. Read more »

For a complete list of CAD meetings, conferences, training sessions, and more, check out our calendar of events on