Introduction to AutoCAD

1. INTRODUCTION

Advantages of AutoCAD

1. Designs can be drawn with greater accuracy.
2. Drawings get prepared in relatively shorter duration.
3. It enhances the productivity and quality of designs.
4. AutoCAD software is cost effective and highly affordable.
5. It facilitates easy modification and revision of drawings.
6. It reduces the manpower requirement.

1.1 Loading Software, Screen organization

1.2 Entering commands: menus, command line, function keys

1. Menu Browser button

Click this button to access a complete list of commands in the menu bar and to search for Help Information. It is situated at the left top of the AutoCAD screen as shown in section 1.1.

2. Ribbon

The ribbon contains commands in a set of tabs for performing tasks. You can change the set of tabs as you like for performing the tasks.Ribbon

3. Workspaces toolbar

This toolbar shows the current selection of workspaces. Besides, you can also switch to other workspaces while working on your drawings.

4. Drawing area

The drawing area is where you create and place your drawing objects.

Besides, the text and graphics screen are the two different screens available in drawing editor. The drawing area where we draw objects is called graphics screen, whereas text screen is where all the commands you provide are listed as shown in the figure below.

5. Command line

The command line shows the command that is being executed, and then messages from that command to draw objects. You can create your drawings objects by using appropriate commands on this command line part.

All the AutoCAD commands can be executed in the command prompt. Many commands have one option letter aliases which is its shortcut command and it can be typed in the command line instead of the complete command word. For instance, 'LINE' is a complete command word for making straight lines and 'L' is a shortcut command alias of the 'LINE' command.

1. Type whatever command you desire in the command line

Command: CENTER

or

2. Type the command's alias.

Command: C (Hit ENTER)

3. Type an option in the command line

Note: Many AutoCAD commands are completed only after you hit the ENTER key. And, you know that when you see a blank command line, you are no longer in an AutoCAD command.

6. Status Bar

It is the area that lies below the command line. It shows the messages and coordinates, the current time, modes, and so on.

In order to activate modes such as GRID, SNAP , OSNAP, ORTHO and others, you must double-click on the mode to change it.

Note: You can also right click on the status bar to see the options.

1.3 Commands and System Variables

Simply, we can understand commands as orders given to AutoCAD to draw desired objects. It is processed by providing the standard command names on the command prompt.

System Variable:

System variables are the settings that the AutoCAD checks before it decides how to do something. Most of the system variables are controlled by the options command, but you can also change the value of a system variable by simply typing its name at the AutoCAD command line and pressing Enter.

1. MENUBAR:

When the MENUBAR is 1, AutoCAD displays its traditional classic menu bar below the application title bar. If the MENUBAR is set to 'zero' (its the default value), the menu bar doesn’t appear.

2. DIMASSOC:

DIMASSOC controls how the AutoCAD dimension objects are created. It controls the associativity of dimension objects and whether dimensions are exploded or not.

0 It creates a exploded dimension. There isn't any association between the various elements of dimension. The lines, arcs, arrowheads and text of a dimension are drawn as separate objects.

1 It create a non-associative dimension object. The elements of the dimension are formed into a single object. If the definition point on the object moves, the dimension value is updated.

2 It creates an associative dimension object. The elements of the dimension are formed into a single object, and one or more definition points of the dimension are coupled with association points on geometric objects. If the association point on the geometric object moves, the dimension location, orientation, and value are updated.

DIMASSOC is not stored in a dimension style.

3. MIRRTEXT:

You’ll frequently build up a drawing by mirroring already-drawn components of it. In other words, you can flip the objects about a given axis in order to create a symmetrical mirror image.

Mirroring is useful for creating symmetrical objects because you can draw half part of the object in no time and then mirror it instead of drawing the whole object by yourself.

You can flip objects about an axis called a mirror line to create a mirror image. To specify this temporary mirror line, you must enter 2 points. You can choose whether to erase or keep the original objects in the drawing area.

1.4 Coordinate System: entering distances and angles

Using coordinate system is a simple mathematics that we have already learned. We can use these coordinate systems to plot the drawings in AutoCAD.

Basically, there are three coordinate systems. They are:

1. Absolute coordinates
2. Relative coordinates
3. Polar coordinates

Absolute coordinates:

It simply uses the coordinate’s points (x, y) to specify the required points on the drawing screen. Type x, y coordinate when AutoCAD asks for a point.

For example:

Starting point: (2, 2)

To point: (4, 2)

To point: (4, 3)

To point: (2, 3)

To point: (2, 2)

Relative coordinates:

Simply, we need @ just before the x, y where ‘x’ and ‘y’ are the distance of any drawing part to be specified. Type @x, y coordinates when AutoCAD asks for a point.

For example:

Starting point: pick point (any arbitrary point)

To point: @2, 0

To point: @0, 1

To point: @-2, 0

To point: @0, -1

Polar coordinates:

Type @distance

For example:

Starting point: pick point (any arbitrary point)

To point: @2< 0

To point: @1< 90

To point: @2< 180 or, @-2< 0

To point: @-1< 90

1.5 Starting a new drawing: naming and saving, ending session

New Drawings:

NEW Command: It creates a new drawing file.

You can create new drawing file whenever you want. You just have to follow the following commands to get new drawing files.

1. Choose File, New.

or

2. Press CTRL + N

or

3. Click the New icon.

or

4. Type NEW at the Command prompt.

i.e. Command: NEW

You can choose any one of the above options for creating a new drawing. Then,

5. Click The OK button.
6. Save the drawing as another name.

Saving Drawings:

SAVE and SAVEAS

Saves are the most recent changes to a drawing. If the first time an unnamed drawing is saved as a file, the “Save As” dialog box appears. AutoCAD automatically saves its drawings as files with extensions ending in .DWG.

The following method can be applied to save the existing drawing file.

1. Choose File, Save or Save As.

Or,

2. Type SAVE or SAVEAS in the command line.

i.e. Command: SAVE or SAVEAS

3. Press ENTER
4. Type A new drawing name or keep the existing drawing name. Then,
5. Click The OK button.

Ending:

Just close the AutoCAD window, a dialog box will appear, if you want to save the existing file then click on ‘Yes’ otherwise click on ‘No’. If you want to go back to the drawing page then click on ‘Cancel’.

Or,

Type Close in the command prompt.

i.e. Command: close