AutoCAD System Variables

AutoCAD is a complex program and one of its major selling points is that it is highly customizable. Every user will use AutoCAD differently. Some use icons, some use command line prompts. Each drawing is also different. You may have different text heights, or dimension styles from one drawing to the next. To keep track of these different parameters, AutoCAD uses a large number of system variables to do this. You have recently used one system variable: LTSCALE. This could have been changed in the Linetype dialog box, but typing LTS is easier and quicker.

A system variable is a configuration setting that can be changed by the user. You just type in the name of the variable you want to change and enter the new value.

Command: TEXTSIZE

Enter new value for TEXTSIZE <0'-6">: 10 <ENTER>

Some system variables can not be changed, these are known as read-only variables. Here is an example of each:

SYSTEM VARIABLE	CURRENT VALUE	TYPE
TEXTSIZE	0.200	USER CONFIGURABLE
ACADVER	20.1s (LMS Tech)	READ ONLY

Most of AutoCAD's system variables are changeable. This allows for quick customization as well as easier programming.

Once you have used AutoCAD for a while, you may find that it is easier to redefine a system variable than to go through a dialog box to get the same result. In some cases, the only way to make these changes is through the system variable itself. Unfortunately, there are no shortcuts for entering these, you have to either remember them, or have a list nearby. Some of them are quite straightforward as to what they do, but some are rather cryptic and make it difficult for memorization.

If you start to learn programming for AutoCAD (LISP, VBA, C++), you will likely use system variables a lot to have your program control AutoCAD.

Warning: Don't change system variables unless you know exactly what you're doing.

To see a list of all of the AutoCAD system variables, follow these steps:

Command: setvar <ENTER>
Variable name or ?: ?<ENTER> Variable(s) to list <*>:<ENTER>

It shows you what the settings were for a particular drawing at a specific time. The list also shows you which system variables are read only. For a listing of these in AutoCAD, click here.

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