25

Ten (Or So) Differences between AutoCAD and AutoCAD LT

This book is aimed at users of both the full version of AutoCAD and AutoCAD LT. Throughout the text, you find icons in the margin that highlight places in our descriptions or steps that are significantly different between the two versions.

Rather than make you go through the entire text (not that it wouldn’t be a highly rewarding task!) looking for tidbits of information, in this chap-

ter we gather the ten most significant differences between the two versions.

Price

Most important to many people — especially if you work in 2D drafting exclusively and don’t see a need to spend a lot of time learning AutoCAD’s customization languages or 3D capabilities — is the much lower cost

of AutoCAD LT. You can buy either version online (visit www.autodesk.com and click Purchase, and then click Shop Online).

3D Abilities

This may be the most significant difference for some users. If you want to model in 3D, you have no choice but to use the full version. In AutoCAD LT, you can open

and view 3D models created in the full version of AutoCAD,

but you can’t create new ones or edit them, other than to move,

copy, or delete them. The only 3D construction you can do in AutoCAD LT is to apply a thickness (height) property to line work. (In AutoCAD, thickness means perpendicular to the drawing plane; don’t confuse it with width, which applies to objects on the drawing plane.)

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544 Part VI: The Part of Tens

And even if you can open 3D models from the full version in AutoCAD LT, it’s not easy to view them. Only a limited number of preset viewing positions are available, unlike the full version where you can rotate or orbit around your model to your heart’s content.

Finally, because AutoCAD LT is really a 2D drafting program, it has minimal visualization or presentation capabilities, while the full program can display 3D models in several built-in visual styles ranging from a simple wireframe mode through to full photorealistic rendering complete with shadows, reflections, and a humongous materials library.

Customization Options

This one is also a biggie for many people. Talk to seasoned AutoCAD users at work or your local user group, and you’ll find that their key to happiness is being able to customize AutoCAD so it does what they want with minimum amounts of time or effort. The full version of AutoCAD supports a number of

Application Programming Interfaces, or APIs. These include AutoCAD’s very own programming language — AutoLISP — and its marginally friendlier sibling Visual LISP, ActiveX Automation, and compiled language programming using ObjectARX or Microsoft’s .NET framework.

Although you can do simple customization in AutoCAD LT — for example, creating or modifying toolbars, writing scripts, or using custom hatch patterns or linetypes — none of the higher-level programming described in the preceding paragraph is possible in LT.

Network Licensing

Once again, the paradigm is big engineering company versus home-office doodler, and the assumption is that AutoCAD LT users have no need for a network license. With regular AutoCAD, you can get a network license that makes things pretty easy to administer. For example, you can have a 10-seat license that lets AutoCAD run on any 10 out of the 20 machines in your office, providing no more than 10 run at one time. If you’re an LT user and you have 20 machines in your office, you’ll need 20 licenses, one per machine, even if there are never more than 10 copies of AutoCAD running at one time.

Express Tools

The Express Tools are a set of officially unsupported but nevertheless reliable bonus commands. They include useful utilities and previews of functionality that may end up built right in to future versions of AutoCAD. There are additional drawing and editing commands, a far more elaborate hatch routine

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Chapter 25: Ten (Or So) Differences between AutoCad and AutoCAD LT 545

than the regular HATCH command, and commands for working with blocks and xrefs, text, dimensions, and layouts.

Because most of the Express Tools are written by using the APIs mentioned in the “Customization Options” section, they won’t work in AutoCAD LT. On the positive side, sometimes a few of the Express Tools are moved into the core of the AutoCAD executable; because they’re not using one of those APIs we mention earlier, they can be made available to AutoCAD LT. For example, AutoCAD LT 2012 added the OVERKILL command for weeding out duplicate objects that had previously been an Express Tool.

Parametrics

We cover parametrics in Chapter 19 of this book, and we point out that AutoCAD LT is extremely limited in this area. Yes, there’s a Parametric tab, and a Parameters Manager, but in LT, the Manager doesn’t have a lot of clout. You can’t create parameters with LT, but you can delete them, and therefore do a lot of damage to a helpless DWG file. If you like the idea of your drawing geometry changing when you change the value of a dimension, then you really ought to think about the full version of AutoCAD rather than LT.

Standards Checking

Standards — as in drafting standards — are important to maintain in design offices. With standards checking, you configure a DWS file (a DWG file set up with your standard layers, text, and dimension styles, layouts, and so forth), and then compare your current drawing, or drawings done by outside consultants, with that DWS file to ensure that they conform to your office standards. AutoCAD LT doesn’t support standards checking.

Data Extraction

As we explain in Chapter 17, attributes are variable text strings that you create as part of a block definition. The data in the attributes can be edited or extracted easily in regular AutoCAD and nearly as easily in AutoCAD LT, but AutoCAD LT lacks the full version’s Data Extraction Wizard, which extracts information from objects and from attributed or nonattributed blocks. If the ability to use all the data in your AutoCAD drawings is important, choose the full version.

MLINE versus DLINE

Here’s a case where AutoCAD LT beats its big sibling! AutoCAD (full version) includes an extremely unwieldy command called MLINE for drawing multiple

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546 Part VI: The Part of Tens

parallel lines. You can draw such lines in the same way you pick points for the LINE command, but multilines are unintuitive to configure and pretty darned difficult to edit.

AutoCAD LT doesn’t have MLINE, but it does have a different command called DLINE. DLINE (Double LINE) may not draw more than two parallel lines, and it can’t add colored fills, but it’s logical to use and much easier to edit. And sorry, AutoCAD users (we’ve been waiting to write that for the whole book!), but you don’t have DLINE.

Profiles

Throughout the book we reference the Options dialog box. This is the place where you make both drawing-specific and systemwide settings so you can configure the program to work the way you want. In the full version of

AutoCAD, you can save these settings as named profiles and switch between them on the Profiles tab of the Options dialog box. For example, you can have one profile with a white drawing background and another with a dark background. Or you can have different profiles that point to different client support files. If more than one person shares a computer, each person can have his or her own profile.

You’ll find profiles only in the full version, though — there is no Profiles tab in AutoCAD LT’s Options dialog box, because AutoCAD LT doesn’t support profiles. Any changes you make to LT’s options become the current defaults, but they can’t be saved and restored later.

Reference Manager

Reference Manager is a free-standing program that isn’t part of AutoCAD or AutoCAD LT. If you have the full version installed, you’ll find Reference Manager on the Windows Start menu. Reference Manager helps you make sure that any dependent files (for example, font files, images, or xrefs) are included when you ship a set of files anywhere. There’s no technical reason why AutoCAD LT shouldn’t include the Reference Manager; but it doesn’t.

On the other hand, if you have both AutoCAD and AutoCAD LT in your office, then you can use the Reference Manager on drawings created by LT, and why not, because AutoCAD and AutoCAD LT use the same file format.

And The Good News Is . . .

Unless you mess with things, particularly as indicated in the 3D and parametrics sections, drawings will survive a round trip out to LT and back to standard AutoCAD.

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26

Ten System Variables to Make Your Life Easier

System variables are settings that AutoCAD checks before it decides how to do something. For example, if you set the system variable SAVETIME

to 10, AutoCAD saves your drawing file automatically every ten minutes; if you set SAVETIME to 60, the time between automatic saves is one hour. Hundreds of system variables control AutoCAD’s operations.

Most system variables are controlled by the Options command, but you can also change the value of a system variable just by typing its name at the AutoCAD command prompt and pressing Enter. AutoCAD displays the current value of the system variable setting and prompts for a new value.

Press Enter to confirm the existing setting, or type a value and press Enter to change the setting.

The three kinds of system variables in the AutoCAD world are

Those saved in the Windows Registry: If you change this kind of system variable, it affects all drawings when you open them on your system, but not necessarily on other computers.

Those saved in the drawing: If you change this kind of system variable, the change affects only the current drawing, but on any computer. The drawing icon in the Options command dialog box indicates those that are saved

in the drawing. If you change these and then save the drawing as a template, all subsequent drawings

started from this template will inherit these values. We cover templates in Chapter 4.

Those not saved anywhere: If you change this kind of system variable, the change lasts only for the current drawing session.

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