AutoCAD R12 Tutorial 1


	FBE AutoCAD Page

Stephen Peter, S.Peter@unsw.edu.au

Introduction

In this first tutorial you will learn how to log onto the computers in the CAD Lab, start AutoCAD, save a drawing, enter a command, and will learn a range of common drawing commands.

If you haven’t done it yet, please complete the OpenWindows tutorial, and set your account password.

Starting AutoCAD

Start autocad by moving the mouse until it is over the screen background and then press the right mouse button, to display the 'Workspace' menu; from this menu select "CAD". After a moment a small dialogue box will be displayed (see figure 1), make sure 'AutoCAD' is ticked and then click on "Do it" using the left mouse button.

AutoCAD can also be started by typing:

    acad  [return]

in the command window.

Figure 1 The CAD Lab. AutoCAD startup Dialogue Box.

Once the two autocad windows appear, move the mouse around until you see a crosshair cursor. The autocad graphics window (the one in front) has five main areas:

The 'drop down' menus, located along the top of the screen.
The status area, located below the drop down menus.
The graphics area, located below the status area.
The screen menu, located to the right of the graphics area.
The command line, located below the graphics area.

Figure 2 The AutoCAD graphics window.

Saving a Drawing

Before saving the drawing, you'll draw a rectangle: make sure the mouse is inside the autocad graphics window, then type:

    rectang  [return]
    1,1      [return]
    11,8     [return]

This will draw a 10x7 rectangle, which should fit comfortably in the AutoCAD Graphics Area (note that the text you type is displayed in the 'command line' area at the bottom of the window). If you type the wrong letter, you can use backspace or delete to correct your typo, or ^C (hold the [crtl] key and press C) to cancel the command.

Autocad has four commands for saving drawings!

SAVE: displays a dialogue box requesting a drawing name, if the drawing has already been saved it's name will be displayed as the default name to use when saving.
SAVE AS: this command is the same as SAVE.
QSAVE: save the drawing without requesting a drawing name, if the drawing has no name it will display a dialogue box like SAVE.; QSAVE is the best save command to use once you’ve given the drawing a name (for example by saving it).
END: saves the drawing and exits from autocad, if the drawing has no name it will display a dialogue box like SAVE.

Save you work regularly! There is a proverb that goes something like: “risk only as much as you can afford to lose.”

Use the first option, type:

    save   [return]
    tut1   [return]                 use another drawing name if you wish!

Note that you can also press [space] instead of [return].

We will now draw some more graphics and then save and exit autocad; type:

    line   [return]

Move the crosshair to near the bottom-left of the rectangle and click the left mouse button, then move the crosshair to the top-right of the rectangle and again click the left mouse button.

press

    [return]                     to terminate the line command.

then press

    [return]                     to re-start the line command!!

Draw a line from the top-left to the bottom-right of the rectangle.

press

    [return]                     to terminate the line command.

Now type:

    end   [return]               this will save the drawing and exit autocad.

Starting Autocad With an Existing Drawing

The 'File Manager' is located on the right of the screen in the normal openwindows layout, if you look in the file manager you should see an "icon" with the name of your drawing below it. When you've found it, move the mouse to the "icon" and double-click using the left mouse button. Once the 'CAD Lab. Autocad startup’ dialogue box appears, click on "Do it" using the left mouse button. In a few moments the autocad windows will appear and then your drawing will be drawn in the graphics area.

Command Entry

There are three ways to enter commands in autocad:

Select the command from one of the drop-down menus.
Select the command from the screen menu.
Type the command in the command line.

Until now you have been entering commands using the third method.

From now on, when I want you to select a command from the "drop-down menus" the instruction will be similar to:

    /Draw . Circle . Centre, Radius/

This means click on the 'Draw' item of the top (drop-down) menu, using the RIGHT mouse button, then click on the 'Circle' item, also with the RIGHT mouse button, and finally click on 'Centre, Radius', using the LEFT mouse button.

If a menu item has a small triangle next to it, then a menu will be displayed if the RIGHT mouse button is used to select then item; if the LEFT mouse button is used instead then a “default action” takes place. The “default action” is the item on the sub-menu that is circled.

When I want you to select commands from the "screen menu" the instruction will be similar to:

    |Draw . Line:|

This means click on the 'Draw' item of the screen menu, using the LEFT mouse button, then click on the 'Line:' item, using the LEFT mouse button.

The screen menus are a hangover from older versions of autocad and so don't appear the same as the drop-down menu, and don't obey the "RIGHT button = display menu" rule that works almost everywhere else in OpenWindows.

When using the screen menu, you can always return to the top level menu by simply clicking on the 'AutoCAD' item at the top of the menu.

If the screen menu item has a ":" at the end then the item is an AutoCAD command, if it has "..." at the end the item will display a dialogue box, if the item has nothing on the end the item will display a new menu if picked.

The screen menus generally list the autocad commands exactly, whereas the drop-down menus often list a more meaningful word. For example, the AutoCAD command to draw a polyline (a series of joined lines) is PLINE and it is located:

    |Draw . next . PLINE:|

while the drop-down menu has:

    /Draw . Polyline/

Coordinate Systems

When specifying positions you can use Cartesian or Polar Coordinates. Cartesian coordinates are simply a X value, a comma, and a Y value, for example: 11,11. Polar coordinates are a Distance followed by a < symbol and an angle, for example: 10<25. Angles are measured in degrees, with 0 = East and 90 = North. Any of these numbers can have decimal values.

AutoCAD is a three dimensional CAD system, so you can enter XYZ values instead of the XY values shown here.

The positions specified above are "absolute coordinates", because they specify a particular position. AutoCAD can also use "relative coordinates" to specify a position relative to the current position, for example: @5.6,-3.4 and @16.32<62.

Select:

    /Draw . Polyline/

Click on /Draw/ with the RIGHT mouse button and then /Polyline/ with the LEFT mouse button, this chooses the “default” polyline.

then type:

    6,1      [return]                absolute cartesian coordinate
    @5<45    [return]                relative polar coordinate
    @5<135   [return]
    @5<225   [return]
    c        [return]                "close" the shape.

This should draw a “diamond” (rectangle rotated) shape. If you make a mistake, type: u [return].

Snap Modes

It is often useful to be able to draw something from (for example) the end of another shape. AutoCAD has a large selection of "snap modes" for this purpose. The most commonly used snap modes are "Endpoint" (which snaps to the end of the selected graphics entity) and "Intersection" (which snaps to the intersection of two graphics entities).

The menu of snap modes can be displayed in three ways:

simply click the RIGHT mouse button with the mouse inside the graphics area, and then click on the snap mode using the RIGHT mouse button;
click on the "* * * *" item on the screen menu and then the snap mode using the LEFT mouse button;
select /Assist . Object Snap/ using the RIGHT mouse button, then click on the snap mode using the LEFT mouse button.
The last method is particularly useful because the menu displayed includes a "pin" (in the top left corner); if you click just to the left of the pin the is "pushed in" and the menu remains displayed on screen. Note that most of the drop-down menus have these pins!
Select:
```
    /Draw . Arc . 3-point/
```
then click the RIGHT mouse button and select "Midpoint" with the RIGHT mouse button and select the left side of the bottom of the polyline you drew before. Then use the midpoint snap to enter points on the right side at the bottom and then the top of the polyline (see figure 3).

Figure 3 Arc construction.

Finally...

Lastly, I want you to draw a rectangle in the diamond shape, another diamond inside that rectangle, a circle inside that diamond and a horizontal and vertical line also inside the last diamond (see figure 4)! Each shape should touch the Midpoints of the previous shape...

If you use the Midpoint Snap Mode , for each point(!), you should be able to do draw the shapes without much trouble.

Draw the circle using the ‘3-point’ option like the arc that you drew earlier.

If you make a mistake, type: ^C (hold the [crtl] key and press C) then type: u [ return] (“u” is the ‘undo’ command).

If the screen gets messy, type: r [return] (“r” is short for ‘redraw’).

Figure 4 Finished Tutorial 1 drawing.

Logging Off

That’s all for tutorial one, type:

    qsave    [return]                saves your drawing.

If there’s still some time before the end of the tutorail, select:

    /File . New/

draw a 10x7.5 rectangle, and then draw a Australian Flag, either the current flag or a new one! Once you have drawn the rectangle draw the rest using the LEFT mouse button ("by eye") or using Snap Modes.

When you are ready to leave, type:

    end      [return]                saves the drawing and exits AutoCAD.

To log off, move the mouse to the (blue) screen background and click the RIGHT mouse button, then click "Exit..." and finally click "Exit" to confirm the action!

FBE AutoCAD Page

2D-R12 Tutorial 2


Last Update : 8 April 2000 Major Revision : 29 October 1997 SEARCH . FBE SITEMAP		Disclaimer . Webmasters Page Contact : Stephen Peter Email : s.peter@unsw.edu.au