AEC Tech News #100 (June 26, 2003)

25 Jun, 2003 By: Lachmi Khemlani

In response to my last newsletter profiling some reader responses to my recent AutoCAD 2004 review in CADENCE, a few readers contacted me to request a write-up on AutoCAD LT 2004. The current issue looks at this lower-cost alternative to AutoCAD, focusing in particular on how it differs from the full-blown version.

Overview of AutoCAD LT 2004

Priced at $725, AutoCAD LT 2004 is far more affordable, compared to the $3,750 price tag of AutoCAD 2004. It is supposed to be the only 2D CAD software that is 100-percent compatible with AutoCAD 2004 and other AutoCAD 2004-based software, allowing problem-free drawing exchange with other design professionals who are on the AutoCAD platform. AutoCAD LT is targeted towards those users who require full DWG file format compatibility for their drafting and detailing tasks, but do not need 3D features, customization ability, or third-party add-ons.

The new version of AutoCAD LT has most of the enhancements available in AutoCAD 2004: the revamped DWG file format that reduces file size and increases speed; a redesigned interface with auto-hide and transparency abilities for modeless dialogs; improved multi-text creation and editing; customizable tool palettes that can contain frequently used blocks and hatches; digital signatures for drawing security; a new, plot-ready, multi-sheet DWF file publishing format for secure and easy electronic sharing of data, which can be viewed and printed with the free Autodesk Express Viewer; multiple Redo and Undo; revision cloud tools for creating free-form clouds or converting existing objects into cloud shapes; a new Communication Center superseding the Today window that provides direct notification of product-related information and is available via an icon on the status bar; and direct linking to Buzzsaw project hosting via a standard drive letter.

Differences between AutoCAD LT and AutoCAD

The interface of AutoCAD LT seems identical to AutoCAD's at first glance. While it has the same software architecture and technology, the program differs from AutoCAD in several significant ways. It has no 3D capability at all and cannot be customized through APIs, such as Visual LISP, VBA, and ActiveX. The CAD Standards tools for configuring standards, checking standards, and translating layer attributes from one file to another are not available. There are also no advanced network license management features, such as the reporting and flexible license management tools available in AutoCAD. Additionally, AutoCAD LT lacks layer and attribute management tools, the ability to edit xref files in-place, quick dimensioning, additional viewport options, database connectivity enhancements, drawing caching for faster switching between tabs, and the capability to use multiple processors on a single system.

Furthermore, some new features in AutoCAD 2004 have not been incorporated in AutoCAD LT 2004. While you can attach a digital signature to an AutoCAD LT file, the additional security option to attach a password that encrypts the drawing and prevents unauthorized viewing is not available. (You can, however, read password protected DWG files created in AutoCAD 2004 or AutoCAD 2004-based products.) The new DWG format allows AutoCAD 2004 to have true (24-bit) color and color libraries such as PANTONE, RAL DESIGN, and RAL CLASSIC; these features are not included in AutoCAD LT 2004. The new gradient fills feature, applicable in AutoCAD 2004 through the Hatch tool, is also missing in the LT Version. Finally, the critical xref enhancements in AutoCAD 2004--the ability to separately open and edit xrefed files, facilitating collaborative work on the same drawing set, and automatic notification when an xref has changed--are not available in AutoCAD LT 2004.

The Issue of Backward Compatibility

Both AutoCAD LT 2004 and AutoCAD 2004 create the same native DWG file format, which accounts for the 100-percent file format compatibility between them. But this also means that AutoCAD LT 2004, just like AutoCAD 2004, does not provide an option to directly save the DWG file to AutoCAD R14. Several readers wrote in to say that they regard this a serious limitation, which prevents them from upgrading to the new version. A Dotsoft representative told me that in a quick poll conducted at on the importance of the ability to save to R14 format, a solid 2/3 (66-percent) of the 465 respondents so far considered this lost ability "very important" or "critically important." Only 16-percent of the respondents found this ability unimportant.

This issue of backward compatibility also prevents AutoCAD LT users from fervently embracing the new version, despite the significant improvements it provides. One practicing architect in his 44th year of practice, successfully using AutoCAD LT instead of AutoCAD, wrote (edited for clarity):

"I have been using AutoCAD LT for the last 15 years, quite successfully, and I like it because we don't need the 3D and shading features. We work with both clients and consultants who use older versions of AutoCAD, Release 12 or higher, and need to open and save our/their drawings in a version they want. We are among the 'eighty-plus' percent of all AIA members with staff sizes of only 1-5. During my years of peak activity, we were one of those still relatively small firms with 10-15 staff members. I understand there are well over one million LT packages out there. We do, when necessary, use xrefs and are learning to make more use of Paper Space. Our three workstations use LT 2000 and 2000i and I do not want to upgrade and find myself not able to communicate with our clients and consultants. We are solving our 3D needs quite well with SketchUp and other SketchUp add-ons."

Perhaps Autodesk needs to rethink and reinstate the ability to save back to R14.

Extensions and Alternatives

A variety of add-ons from various vendors are available for those who want to use AutoCAD LT, but need added capabilities similar to those provided by AutoCAD. For instance, at, you can find AutoCAD LT add-ons for 3D modeling, rendering, imaging, shading, true color, gradient fills, a Lisp enabler, and customization tools. Many of these do not yet work with the latest release, AutoCAD LT 2004, but I expect it's only a matter of time before they catch up.

It should be noted, however, that many such add-ons are not supported by Autodesk, as AutoCAD LT was not intended to be a development platform. A company spokesperson told me that Autodesk may, in the normal course of development, make programming changes in future versions, which may cause such add-ons to cease functioning with those AutoCAD LT versions. Thus, using such extensions is not without its share of risks.

If 100-percent DWG compatibility is not a must, there are several other inexpensive alternatives for drafting and detailing. I have reviewed several of these in earlier issues, such as IntelliCAD (, SmartSketch (, Microsoft Visio (, and Graphite ( I will continue to look at more CAD alternatives in future newsletters.

Relevant Links

AutoCAD LT 2004: