AutoCAD Release 13 for Windows NT

A longtime standard excels in a new environment

Autodesk's AutoCAD is the granddaddy of all drafting programs. The currentincarnation, release 13c4 (R13), takes more than 200MB on a CD-ROM and shipswith nearly 15 pounds of documentation (with more available only online athttp://www.autodesk.com/products/autocad/r13c4/13c4idex.htm).The initial release of AutoCAD R13 included versions for UNIX, MS-DOS, andWindows 3.X. A few months later, Autodesk added a Windows NT version. I set outto discover how well NT and AutoCAD work together.

The Application
AutoCAD is a sophisticated design and drafting package for developingcomplex drawings. Screen 1 shows a drawing created using AutoCAD. The programsupports 2D and 3D drawing and rendering, and sophisticated features such assolid modeling. Whereas a 3D rendering typically involves the cosmetics of a 3Dobject's surface, true solid modeling includes the attributes, such as mass anddensity, of real 3D objects. Unlike drawing files other programs create, anAutoCAD drawing is a full database of information that completely describes theobjects ("entities," in AutoCAD terms) you draw. In fact, AutoCAD letsyou link drawings to external databases so you can use drawings, for example, togenerate a bill of materials. You can even use the information in an AutoCADdrawing to directly control automated machining tools.

AutoCAD has grown into its own industry--the AutoCAD Resource Guidethat ships with the product has more than 300 pages of third-party add-ons,enhancements, and of course, T-shirts. Some of these add-ons, such as acalculator, provide simple features and others, such as 3D wire-frame unfoldingand finite element analysis, are more sophisticated. You can bet that if a taskhas anything, even remotely, to do with CAD, someone has created an add-on forit in AutoCAD.

System Requirements
Everything about AutoCAD is heavy duty, which means if you want to seriouslywork with this program, you need a serious workstation. AutoCAD for NT runs onthe Intel and Alpha platforms. Autodesk recommends at least 32MB of RAM; I found40MB to be a comfortable minimum when working with most drawings. However, youmight need 48MB or more for large complex drawings--particularly for rendering.A typical install requires 50MB of disk space and a generous swap file;fortunately disk space is cheap and plentiful. And don't even thinkabout running AutoCAD on anything less than a fast Pentium. I didn't have timeto test the program with a Pentium Pro, but as a pure 32-bit application thatextensively uses floating point arithmetic, AutoCAD must work particularly wellon this new processor.

Installation
Installing AutoCAD is easy. The program uses no external protection devicesfor the single-user US version. However, you'll need to dial a toll-free numberto get an authorization code for each copy (this is pretty painless). The firsttime you run AutoCAD, you must go through a reasonably straightforwardtext-based configuration operation.

Running on NT
Once installed, AutoCAD ran flawlessly under NT with a noticeable advantageover previous versions: With the R13 release under NT, you can now open multipleAutoCAD sessions. Previously, AutoCAD ran only one session at a time: Windows3.X does not support the multiple instance functionality. Because AutoCAD is asingle document interface (SDI) application, the only way to open a seconddrawing is to open another AutoCAD session. So being able to run more than onesession at a time is vital if you want to cut and paste from one drawing toanother. Running two AutoCAD instances, however, requires patience or lotsof RAM. I recommend an extra 8MB of RAM for each additional instance if you wantto do a lot of cut and paste operations.

Just for fun, I ran half a dozen instances of AutoCAD; NT did this with notrouble. Each instance grabbed an extra 8MB to 10MB of swap-file space.Switching among the instances took between 3 and 4 seconds (including time toredraw) on my P90 system, which seemed reasonable. When I ran the same testunder Windows 95, I couldn't get beyond the third instance without running intodifficulties. The system either crashed or displayed a blank dialog (always asign of resource problems).

Although AutoCAD runs well under NT, the program is not particularly wellintegrated with some advanced features of NT. For example, the program makeslittle use of the system Registry to store configuration information. Most ofAutoCAD's configuration data is in numerous configuration files, which you mustedit in the program or (worse) using a text editor. Keeping track of andmanaging this information is time consuming and awkward. A better approach wouldbe to have this information in one place where you can use the NT Registryeditor for all configuration needs.

The GUI, the Bad, and the Ugly
As screen 2 shows, the AutoCAD user interface has more toolbars and buttonsthan any application I've seen. However, AutoCAD R13 for NT is still rooted inthe type-a-command method of working. Almost anything you can do from menus,buttons, and dialogs, you can do by typing a command in the ever-present,scrolling command window at the bottom of the AutoCAD screen.

Old-timers who know AutoCAD like the back of their protractors can use thecommand line to rapidly create a drawing, in much the same way that experiencedWindows users know keyboard shortcuts. The difference, however, is that manyadvanced features are available only from the command line. To adie-hard GUI user, this difference can be something of a culture shock. To makematters worse, the large legacy of commands from previous versions means thatmany command names are still obscure (although some are amusing, such as theOOPS command, which undoes a previous ERASE command). Forcing you to use thecommand line for advanced operations makes AutoCAD's learning curve steep. Thisrequirement also makes the overall feel of the program less GUI than I like.After awhile, you realize the toolbars and buttons are just a thin veneer overwhat is, at heart, a command-line program.

Out of curiosity, I entered a few commands from an old AutoCAD release 2book. Without exception, they all worked, although R13 contained more optionsfor each command. I can't think of any other software available for the PC thatboasts such heritage.

Put to the Test
To see how well AutoCAD performed under various loads on various OSs, Itested AutoCAD using NT 3.51 with Service Pack 3, Win95, and Windows forWorkgroups (WFW) 3.11. I ran the tests on my P90 with 40MB of RAM, stripedSeagate drives on an Adaptec AHA 2940 SCSI adapter, an S3-based Diamond Stealth64 VRAM card, and the new AutoCAD WHIP display driver.

As a basic test, I ran AutoCAD and loaded the sample drawing, robot.dwg,that you see in screen 1. I then rendered this drawing using the defaultrendering settings to produce a reasonably good photorealistic rendering. Theperformance results are in graph 1.

Not surprisingly, WFW 3.11 finished last and failed to render the complexdrawing (robot.dwg) after 7 minutes of disk thrashing. Win95 loaded AutoCAD thefastest, taking just 7 seconds compared to 17 seconds for NT (although NT loadedsubsequent instances quicker than Win95). Drawing load times for NT and Win95were comparable.

Rendering times were always better under NT than Win95 (by about 8% to12%). The rendering test was highly swap-intensive under both Win95 and NT. As aresult, I would have expected Win95's greater available physical RAM to bias theresult toward Win95 (which, presumably, with more free RAM, would have had lessswapping). The reason NT is faster is probably because of its more efficientdisk I/O system, particularly under heavy use, and its more sophisticatedpage-swap algorithms. This is a significant difference because AutoCAD shopsdeal with very large drawings that can strain the swapping system of anyOS.

Doctor's Orders
NT fans are sometimes disappointed when an NT-specific release of theirfavorite application is only a straight 32-bit version of a prior 16-bitimplementation. This situation is certainly the case with AutoCAD in its presentrelease. However, for AutoCAD, this simple conversion is just what the doctorordered. The switch from DOS or Windows 3.X to NT as the underlying OS hasresulted in a notable performance gain. AutoCAD also benefits from theconsiderable robustness that NT offers even large applications. I will beinterested to see how future versions of AutoCAD, which will probablyincreasingly use new Win32 features, will continue to push the performanceenvelope.

AutoCAD is a perfect demonstration of the kind of workstation applicationNT was designed for. During my tests under NT, I never had the impression thatAutoCAD's demands stressed the OS in any way, unlike Windows 3.X and Win95. Tobuild a high-rise building (AutoCAD), you'd better have a strong foundation(NT).