Auto CAD notes 2010 - Introduction to AutoCad Software PDF

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Introduction to AutoCad Software...

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Computer Aided Design and Drafting

AutoCAD 2010

0. INTRODUCTION 0.1 OVERVIEW OF CAD Engineering graphics is the process of defining an object graphically before is constructed and used by consumers. Previously, this process for producing a drawing involved the use of drawing aids such as pencils, ink pens, triangles, T-squares, and so forth to place an idea on paper before making changes and producing blue-line prints for distribution. The basic principles and concepts of producing engineering drawing have not changed, even when the CADs are used as a tool. For this case AutoCAD is the Computer Aided Design under consideration. Computer Aided Design (CAD), also known as computer-aided design and drafting (CADD), is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer. AutoCAD software provides different environments with tools for the purpose of design processes and drafting. This syllabus serves as a guide for learning the basics to produce 2D drawings using AutoCAD. 3D modeling and photorealistic rendering is not covered. For advanced knowledge, it is better to read the Help provided with the software, read any other guide provided by Autodesk or even download tutorials from internet. 0.2 OBJECTIVES OF THE COURSE The main objective of this course is to provide participants with: Basic theoretical and practical knowledge/skills to produce 2D technical\engineering drawings with the aid of AutoCAD Understanding of concepts, tools and methods for drafting and preparing layouts in AutoCAD 0.3 BASIC SKILLS REQUIREMENTS Participants should have the following basic skills: Having practical knowledge/skills and understanding the concepts of hand based technical/engineering drawing Start and shut down the computer Start any application from the Start Menu and desktop shortcuts To be familiar with basic applications such as Microsoft Offices Organizing and managing Files into Folders (Create, Name, Save, and Open Files) The use of the mouse and keyboard

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I. GETTING STARTED WITH AUTOCAD 1.1. AUTOCAD WORK SPACES There are four workspaces supplied with AutoCAD: the 2D drafting and annotation, Initial Setup workspace, AutoCAD Classic, and 3D Modeling. THE 2D DRAFTING AND ANNOTATION WORKSPACE Workspaces are considered task-oriented environments. By default AutoCAD loads the 2D drafting and annotation workspace. This workspace controls the display of what is called the Ribbon, which is used for accessing the more popular commands in AutoCAD. This workspace contains other items such as the Application Menu, the Quick Access Toolbar, the graphic cursor, and the InfoCenter for getting information about commands.

Application Menu

Quick Access Toolbar

Cursor

InfoCenter

Ribbon

AUTOCAD CLASSIC WORK SPACE This workspace differs from the previous workspace in that a number of extra toolbars display in the upper, left, and right vertical portions of the display screen. This workspace does not display the Ribbon.

Application Menu Draw

Quick Access

InfoCenter

Menu Bar

Toolbar

Workspace toolbar

Cursor

Tool palette Modify toolbar

toolbar

While major differences occur at the top of the display screen when you are activating different workspaces, most of the tools available at the bottom of the screen are common to both workspaces.

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Computer Aided Design and Drafting User coordinate system

Command line

Layout tabs

AutoCAD 2010

Zoom tools

Status Bar

Annotation

Quick view tools

Icons

tools

Workspace switching

ACCESSING WORK SPACES If the current workspace is AutoCAD Classic, you can click in the workspace toolbar and choose a different workspace. If however, the current is 2D drafting and annotation, you would click on the workspace switch icon located in the bottom right of the display screen. THE STATUS BAR The status bar, illustrated in the following image, is used to toggle ON or OFF the following modes: Coordinate Display, Snap, Grid, Ortho, Polar Tracking, Object Snap(OSNAP), Object Snap Tracking (OTRACK), Dynamic User Coordinate System(DUCS), Dynamic Input (DYN), Line Weight (LWT), and Quick Properties (QP). Click the button once to turn the mode on or off. A button with a blue color indicates that the mode is on. Right click on any button in the status bar and clicking on the Use Icons changes the graphic icons to text mode icons. Text Icon Used

Icon Used

Drawing Coordinate

Quick Properties

Snap Mode Grid Display

Shaw/Hide line weight Dynamic Input Allow/Disallow dynamic UCS

Ortho mode

Object Snap Tracking

Polar Tracking

Object Snap

To display or hide one of the above modes, right click on any one them, and then choose Display. Note: When navigating through a menu, the above modes are hidden and a brief description of the highlighted command (or option) in that menu is displayed on the status bar.

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COMMUNICATING WITH AUTOCAD The command line AutoCAD uses this space to prompt you for information. As a command is selected from a toolbar, AutoCAD prompts the user with a series of steps needed to complete this command.

Specify Command Options When you enter commands on the command line, AutoCAD displays either a set of options or a dialog box. For example, when you enter circle at the Command prompt, the following prompt is displayed:  You can specify the center point either by entering X, Y coordinate values or by using the pointing Execute Commands To execute commands, press SPACEBAR or ENTER. Repeat and Cancel Commands If you want to repeat a command that you have just used, press ENTER or SPACEBAR or right click your pointing device at the Command prompt. To cancel a command in progress, press ESC. Dynamic Input Dynamic input provides a command interface near the cursor to help you keep your focus in the drafting area. When dynamic input is on, tooltips display information near the cursor that is dynamically updated as the cursor moves. When a command is active, the tooltips provide a place for the user entry. Click DYN on the status bar to turn dynamic input on and off. You can turn it off or on by pressing down the F12 key.

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THE APPLICATION MENU The Application Menu provides you with the ability to access commonly used AutoCAD tools. Clicking on the icon in the upper left corner will display the categories. Through the Application Menu, you can create, open, save, print, and publish AutoCAD files. THE MENU BAR In either workspace, Menu Bar provides an easy way to access most AutoCAD commands. Various categories exist such as File, Edit, View, Insert, and so on. TOOLBARS FROM THE AUTOCAD CLASSIC WORKSPACE Activating the AutoCAD Classic workspace will automatically display toolbars. The following image shows the Standard, Workspaces, Layers, Properties, Styles, and Draw toolbars displayed.

Draw toolbar

Workspaces toolbar

Layers toolbar

Standard toolbar

Properties toolbar

Styles toolbar

When working in AutoCAD Classic workspace, six toolbars are already active or displayed in all drawings: Draw, Layers, Modify, Properties, Standard, and Styles. To activate different toolbars, move the cursor over the top of any command button and press the right mouse button. A shortcut menu appears that that displays all toolbars. TOOLBARS FROM THE 2D DRAFTING AND ANNOTATION WORKSPACE To display toolbars as in AutoCAD Classic workspace, click on the arrow at the end of the Quick Access Toolbar and pick Show Menu Bar. When the menu bar displays, click on Tools followed by Toolbars and AutoCAD as shown in the following images. This will display all of the toolbars similar to those that are present in AutoCAD Classic workspace. Pick one of the names from the list to show the toolbar on the display screen. Pick Arrow Here Menu Bar

RIBBON DISPLAY MODES

One click here

A small button with an arrow is displayed at the end of the Ribbon tabs. This button allows you to 5

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minimize the Ribbon and displays more of your screen. Three modes are available that allow you to minimize to the title panels, minimize to the tabs, or show the full Ribbon. TOOL PALETTES Commands can also be accessed from a number of tool palettes. To launch the Tool Palette, click the Tool Palette Window button, which is located I the Standard toolbar of the AutoCAD Classic workspace. If you are in the 2D Drafting & Annotation workspace, first click on the View tab and select tool Palettes. The Tool Palette consists of numerous tabs. Use these tabs to access more popular commands

Modify

Draw

1.2. SETTING DRAWING UNITS OF MEASUREMENT AND ANGLES Before you start to draw, you decide what one drawing unit represents based on what you plan to draw. You also set the format and the number of decimal places. The Drawing Units dialog box is available for interactively setting the units of drawing. Choose Units from the Format heading of the Application Menu to activate the Drawing Units dialog box as illustrated in the following image.

By default, decimal units are set along with four decimal place precision. The following systems of units are available: Architectural, Decimal, Engineering, Fractional, and Scientific.

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Methods of measuring angles supported in the Drawing Units dialog box include Decimal Degrees, Degrees/Minutes/Seconds, Grads, Radians, and Surveyors Units

Selecting Direction in the main Drawing Units dialog box displays the Direction Control dialog box which is used to control the direction of angle zero in addition to changing whether angles are measured in the counter clockwise or clockwise direction.

1.3. STARTING A NEW DRAWING To begin a new drawing file, select the QNEW command using one of the following methods: From the Quick Access toolbar From the Standard toolbar of the AutoCAD classic workspace From the Application Menu (New) From the keyboard (NEW). Entering the NEW command displays the dialog box which provides a list of templates to use for starting a new drawing. 1.4. OPENING AN EXISTING DRAWING The open command is used to edit a drawing that has already been created. Select this command from one of the following: From the Quick Access toolbar From the Standard toolbar of the AutoCAD classic workspace From the Application Menu (Open) From the keyboard (OPEN)

1.5. SAVING A DRAWING FILE You can save drawings using the QSAVE and SAVEAS commands. The QSAVE command can be selected from the following: From the Quick Access toolbar From the Standard toolbar of the AutoCAD classic workspace 7

Computer Aided Design and Drafting

AutoCAD 2010

From the Application Menu (Save) From the Menu Bar (File > Save) From the keyboard (QSAVE) The SAVEAS command can be selected from any of the following: From the Application Menu (Save As) From the Menu Bar (File > Save As) From the keyboard (SAVEAS)

Save Selecting Save activates the QSAVE command, which stands for quick save. If a drawing file has never been saved and this command is selected, the Save Drawing dialog box is displayed for specifying the location where the file will be saved. Once the drawing file has been initially saved, selecting this command causes an automatic save and the Save Drawing dialog box is no longer displayed. Save As Using SAVEAS command always displays the dialog box. This command is more popular for saving the current drawing under an entirely different name. Once a drawing is given a new name through this command, it also becomes the new current drawing file.

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II. CREATION OF GEOMETRIC OBJECTS 2.1. BASIC DRAWING COMMANDS Many of the basic drawing tools can be easily accessed using the Ribbon, Menu Bar, Tool Palette, from the keyboard by typing the name of the command, and Draw toolbar as shown in the following images. Draw Toolbar

Ribbon (Expanded)

Ribbon

Menu Bar

Tool Palette

The following table gives a brief description of the LINE, CIRCLE, and PLINE commands: Button

Tool

Aliases

Function

Line

L

Draw individual or multiple line segments

Circle

C

Constructs circles of specified radius or diameter

Pline

PL

Used to construct a polyline, which is similar to a line except that all segments made with the PLINE command are considered a single object

2.1.1. CONSTRUCTING LINES Use the LINE (or L) command to construct a line from one end point to the other. As the first point of the line is marked, the rubber-band cursor is displayed along with the normal crosshairs to assist in locating where the next line segment will be drawn. The LINE command stays active until the user either executes the Close option or ends the line by pressing ENTER key THE DIRECT DISTANCE MODE FOR DRAWING LINES You can specify a point by moving the cursor to indicate a direction and then entering the distance. To specify a line length quickly, without entering coordinate values, you can 9

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specify a point by moving the cursor to indicate a direction and then entering the distance from the first point. When Ortho mode or polar tracking is on, this method is an efficient way to draw lines of specified length and direction. Procedure: 1. Start the LINE command and specify the first point. 2. Move the pointing device until the rubber-band line extends at the same angle as the line you want to draw. 3. Enter a distance on the command line. The line is drawn at the length and angle you specified

2.1.2. CONSTRUCTING CIRCLES The CIRCLE (or C) command constructs circles of various radii or diameter. Circles may be constructed by radius or diameter. This command also supports circles defined by two or three points and construction of circle tangent to other objects in the drawing. Ribbon

Menu Bar

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2.1.3. CONSTRUCTING POLYLINES Polylines are similar to individual line segments except that a polyline can consist of numerous segments and still be considered as single object. Width can also be assigned to a polyline, unlike regular line segments. 2.1.4. CREATING POLYGONS The POLYGON (or POL) command is used to construct a regular polygon. You create a polygon by identifying a number of sides for the polygon, locating a point on the screen as the center of the polygon, specifying whether the polygon in inscribed or circumscribed, and specifying a circle radius for the size of the polygon. Creating polygons can also be accomplished by locating the endpoints of one of its edges. This is done by using the EDGE command. First you type POL for POLYGON, and then you enter the number of sides. The machine asks you to specify the center of polygon or edge, choose E for edge, and then specify the first and the second endpoint of edge. 2.1.5. CREATING RECTANGLE OBJECTS Use the RECTANG (REC or RECTANG) command to construct a rectangle by defining two points. There are three method of constructing rectangles: By picking two diagonal points By dimensions By area Any one of these method is accomplished by choosing an option from the command window. 2.1.6. ARCS To create an arc, you can specify various combinations of center, endpoint, start point, radius, angle, and direction values. 2.1.7. ELLIPSES The shape of an ellipse is determined by two axes that define its length and width. The longer axis is called the major axis, and the shorter one is the minor axis.

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2.1.8. SPLINES A spline is a smooth curve that passes through or near a given set of points. You can control how closely the curve fits the points. You create splines by specifying points. You can close the spline so that the start and endpoints are coincident and tangent. 2.1.9. REFERENCE POINTS Point objects are useful as nodes or reference geometry for object snaps and relative offsets. You can set the style of the points and their size relative to the screen or in absolute units. Procedures:  To set point style and size

To create a point object

1. Click Format menu, choose Point Style. 2. In the Point Style dialog box, select a point style. 3. Under Point Size, specify a size, either relative to the screen or in absolute units. 4. Click OK.

1. Click Draw menu, choose Point >Multiple Point. 2. Specify the point location. You can snap to a point using the Node object snap. Command entry: POINT

Command entry: DDPTYPE

Point Style dialog box

2.1.10. CONSTRUCTION LINES Lines that extend to infinity in one or both directions, known as construction lines, respectively, can be used as references for creating other objects.

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2.2. USE COORDINATES AND COORDINATE SYSTEMS When a command prompts you for a point, you can use the pointing device to specify a point, or you can enter a coordinate value on the command line. You can enter twodimensional coordinates as either Cartesian (X, Y) or polar coordinates (r, . 2.2.1. ENTER CARTESIAN COORDINATES You can use absolute or relative Cartesian (rectangular) coordinates to locate points when creating objects.

To use Cartesian coordinates to specify a point, enter an X value and a Y value separated by a comma (X,Y). The X value is the positive or negative distance, in units, along the horizontal axis. The Y value is the positive or negative distance, in units, along the vertical axis. Absolute coordinates are based on the UCS origin (0, 0), which is the intersection of the X and Y axes. Use absolute coordinates when you know the precise X and Y values of the point. With dynamic input, you can specify absolute coordinates with the # prefix. If you enter coordinates on the command line instead of in the tooltip, the # prefix is not used. For example, entering #3,4 specifies a point 3 units along the X axis and 4 units along the Y axis from the UCS origin. For example, to draw a line beginning at an X value of –2, a Y value of 1, and an endpoint at 3,4, make the following entries on the command line: Command: line From point: –2,1 To point: 3,4 AutoCAD locates the line as follows:

Relative coordinates are based on the last point entered. Use relative coordinates when you know the location of a point in relation to the previous point. To specify relative coordinates, precede the coordinate values with an @ sign. For example, entering @3,4 specifies a point 3 units along the X axis and 4 units along the Y axis from the last point specified. The following example draws the sides of a triangle. The first side is a line starting at the absolute coordinates -2, 1 and ending at a point 5 units in the X direction and 0 units in the Y direction. The seco...