AutoCAD Release 12. (computer-aided-design software) (Software Review) (Evaluation)
by Brian Matthews

AutoCAD Release 12 is an upgrade wish list for casual users, as well as for hardcore programming hackers and third-party developers. While more powerful and advanced than any other CAD program, previous versions of this premier drawing program foundered in the aspects of speed and ease of use. They required regenerations for all but the slightest size changes, and operators had to memorize and enter archaic commands for even the simplest tasks. As a teacher with more than 20 students, I had to program a command sequence in the early evening and let it run overnight because the equipment and software were so antiquated.

With Release 12, the program's new speed and flexibility take full advantage of 32-bit computing capability, evolving networks, and advanced plotting technology. The difference from previous versions is immediately apparent. AutoCAD has emerged from dweebware into the trendy--and timesaving--arena of graphical user interfaces, with pull-down cascading menus, cursor menus, programmable dialog boxes, TIFF and EPSI raster image inputs and outputs, and internal rendering capability.

Eminently user-friendly, Release 12's pull-down menus also remember your last input choice. Expert users who type commands at the prompt line will find all suboptions of the commands on the side menu, which can be turned off to provide a wider screen. The 3-D capabilities of cameras and lighting angles that distinguish CAD from paper-and-pencil drawings now appear within AutoCAD inside the pull-down Render menu, so you no longer need to enter AutoShade.

The 25 new dialog boxes replace cumbersome line commands in starting and opening drawings (no more hunting around the hard drive), plotting (with a brand-new paper-saving preview option), and customizing.

You can enter the command and quickly change any of the settings without having to scroll through needless text questions. And you can correct mistakes if you catch them before pressing the OK button, or you can simply cancel and start again.

Programmable dialog boxes constitute a veritable revolution for AutoCAD users, allowing a new dialog box to be defined by the programmer rather than by the limitations of the program. The Dialog Control Language (DCL) is incorporated with LISP.

Release 12 brings plotting into the nineties. The plot dialog box allows multiple plotter configurations for both plotters and printers. The plot preview function displays the plot image in partial or full format, superimposing the paper extent over the image. Zoom and Pan ensure that your plot is correct prior to sending it to your output device. I found one error in which a plot set to 1/8 inch = 1 foot 0 inches did not plot to the correct scale and had to be reset to 1 = 96, but Autodesk has apparently compiled a new plotter driver to counteract this oversight.

With the program's ability to output raster files from EPS, FITS, TIFF, GIF, and TGA formats; image resolution as high as 1024 x 768; up to 256 colors; and programmable layers, linetypes, and line widths, perhaps Autodesk should be targeting the desktop publishing crowd. RASTERIN.EXP, a Release 12 AutoLISP Xload function, pulls in the raster image similar to a block.

Even network users have a productivity feature, with the ACAD-P option allowing them to plot from outside AutoCAD without requiring an additional license.

Taking a cue from the Macintosh, Release 12 now lets you alter the verb/noun technique in up to 14 commands using the Pickfirst variable. No more choosing commands and selecting objects--you simply click and drag! And a new Grips feature, the Dgrips dialog box, lets you stretch, move, copy, rotate, and mirror entities as edit functions without going into a command. Entities can be arcs, lines, circles, blocks, plines, or text. The grip, basically an attachment, is a small colored square that appears at definition points of an entity, changing color as it becomes hot (activated). The grips also let the operator grab the endpoint, center, midpoint, and quadrant of an entity without using OSNAP (Object Snap.)

Long, slow regen or hide commands are a thing of the past with the introduction of algorithms that accelerate graphics from 50 percent to 500 percent. In fact, a performance enhancement practically eliminates regenerations for zooms and pans!

Graphics acceleration for Zoom with the old 16-bit display space is finally gone, and in its place a 32-bit vector space now provides an extremely efficient Zoom. I did a Zoom Extent followed by a Zoom Vmax to force a drawing out as far as possible without a drawing regen, and even a Zoom 5000000x (yes, six Os) did not entail a regen--undreamt of in previous releases. The dynamic range of the Zoom command is increased from 50 : 1 up to 5,000,000 : 1 before a regen is issued.

Advanced users and third-party developers will appreciate Release 12's new organizing tools. A means of creating a "tree structure," oct-tree spatial index divides drawing entities into logical groups or sort order.

Release 12 achieves graphic acceleration for faster entity selection and redraws (spatial index) through the new variables of Treedepth and Treestat. Treedepth fine-tunes the oct-tree index. Treestat files report values in both the model and paper space branches of the spatial index.

The AutoCAD Sequel Extension (ASE) enables operators to pass information directly from AutoCAD to a database system without requiring shells. Since nongraphical information can be stored outside the drawing and linked with entities inside a drawing, you can reduce a drawing's size without losing useful data.

New conversion functions convert text strings into decimal values, and a geometry calculator allows you to calculate geometry using command line expression and interaction with existing AutoCAD entities. (For instant insider access to undocumented advantages, you may want to check out the new Release 12 edition of 1,000 AutoCAD Tips and Tricks, a book I edited published by Ventana Press.)

I don't have enough space to include all 174 enhancements in the new AutoCAD Release 12, but you obviously get your money's worth when you upgrade to this version.