AutoCAD Drawing Commands

Drawing Commands

The majority of AutoCAD commands that are used for creating and editing a drawing file can be found under the Drawing, Construct, and Modify pull-down menus. Additionally, the right mouse button opens a pop-up menu that includes commonly-used tools such as object snaps.

Most AutoCAD commands accept a variety of inputs; when using the menu and mouse, you can watch the Command: area to learn the names of commands and the acceptable data input. Note that the default choice for the type of information AutoCAD is expecting is enclosed in angled brackets, <>. For example, if you would like to draw a circle, AutoCAD's default is the following:

• Command:_circle 3P/2P/TTR/< Center point >:

meaning that the next point entered, or the next location clicked will become center of the circle.

Plotting

Plotting an AutoCAD drawing is a two-step process. You must first generate a plot file and then send the plot file to a printer. To generate a plot file you can either type plot at the Command: prompt, or select Print... from the File menu. AutoCAD will open the Plot Configuration dialog box.

For plotting to the ITS printers, you should verify that the upper left hand window reads Generic USC Postscript, that the Paper Size is set to A. Plot To File should be checked. You must also select the window (area of your drawing) you want to plot and a name for the plot file. You can select these by clicking on the Window... and File Name... buttons, respectively.

By default, Scaled to Fit is selected. This means that the selected plot window will re-sized to fit an 8 1/2 by 11 piece of paper. To specify a particular scale, you should uncheck the Scaled to Fit checkbox and type in an appropriate scale. You can then preview your plot by clicking on the Preview... button. The Full preview is slower, but includes all of the plot's detail; the Partial preview gives you an outline of the plot area.

Once you have confirmed all of the plot settings, you can click OK. AutoCAD will return you to the Graphics Window and should display messages in the command area confirming that the plot file is being created. Once the file is created, you can send it to a printer using the UNIX lpr command. For example, if you named the plot file drawing1, and wanted to send the plot to the printer named ps_ucc101, you would then type the command:

• lpr -Pps_ucc101 drawing1.plt

Opening and Saving Drawing Files

To open an AutoCAD drawing, you can either type Open at the Command:prompt or select Open from the File menu. AutoCAD will open a dialogue box that will allow you to either type in a filename or select a file using the graphical display. To open a new file select New... from the File menu. To save a file you can either type save at the Command: prompt or select Save or Save As... from the File menu. The .dmg extension is automatically appended to any AutoCAD filename. Additionally, AutoCAD creates a copy of every file when it is opened as filename.bak as a backup. AutoCAD also "locks" each file when it is open to ensure that only one person can modify the file at a time. Lock files have the extension .dwk and often need to manually be removed if AutoCAD crashes while you are editing a drawing.

AutoCad Programs (Scripts and Lisps)

AutoCAD scripts are text files that contain a number of AutoCAD commands that act on a particular file. A script must have the extension .scr and is invoked on a drawing file using the UNIX command acad drawingname scriptname . AutoLisp provides a version of the lisp programming language that allows the user to modify existing AutoCAD commands and write new commands. For more information about using AutoCAD a copy of the AutoCAD documentation is available in SAL 125 and the Leavey Information Commons. Further AutoCAD resources and lessons can be found on AutoDesk's e-Learning Store at: http://e-learning.autodesk.com.