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FACULTY OF ENGINEERING – UNIVERSITY OF RUHUNA
DEVELOPMENT PROGRAMME AUTO CAD RPGD Rathnaweera
2008
FACULTY OF ENGINEERING,
GALLE, SRI LANKA
Development Programme
2008
Computer Aided Drafting using AutoCAD 1.0 CAD and AutoCAD Commonly, CAD stands for computer Aided Drafting which is used to produce technical drawings using a computer. Today with the development of computer industry, there are many types of software developed for computer Aided Drafting. AutoCAD is one of the leading and most popular software used in the industry.
1.1 Special Features of AutoCAD •
Gives greater accuracy compared to the traditional hand drafting methods
•
Automatic Dimensioning with customized tools
•
Layer Properties
•
Zooming of the Drawing or Part of the Drawing
•
Ability to attach textural information
1.2 Recommended Hardware List below are the hardware requirements for running AutoCAD 2007 on any system.
•
Pentium IV (800 MHZ) or higher
•
512 MB RAM
•
1024 X 768 VGA with true color
•
Installation 550 MB hard-disk space
•
Pointing device (Mouse)
•
CD-ROM Drive
•
Windows XP Professional / Windows 2000 with SP3 or SP4
1.3 The first look at AutoCAD Launching AutoCAD is very simple. Double-click the
shortcut icon or start the
application by clicking
Start » Programs » Autodesk » AutoCAD 2007 » AutoCAD 2007 After a few moments, you could see the AutoCAD 2007 interface as shown in the following figure.
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Properties Toolbar Title Bar
Standard Toolbar
Menu Bar Draw Toolbar Cross Hair
Drawing Area
UCS Icon Command Prompt Window
Scroll bars
Layout Tabs
Coordinate Display
Status Bar
Figure 01: Graphical user Interface (GUI) of AutoCAD 2007 1.4 The Pull-down Menus The Pull-down menus available on the menu bar offer a quicker way to access the commands and functions are the heart of AutoCAD 2007.
Figure 02: Pull-down menu Faculty of Engineering, Galle, Sri Lanka
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1.5 Creating a (ew Drawing When you start a new drawing, follow the following steps. File » (ew from the Pull-down menu or click on the
icon on the Standard toolbar.
Then following Select Template dialogue box will appear
Figure 03: Select Template Dialogue Box A drawing template file contains standard settings. You can select one of the template files supplied, or create your own template files. Drawing template files have a .dwt file extension. By default, drawing template files are stored in the template folder. For the starting, select “acad.dwt” template The behavior of the NEW command is determined by the Startup setting on the system tab of the options dialog box.
By default, “Do not show a startup dialog” option is selected in the system tab of the options dialog box. When you select the “show Startup dialog box” option, AutoCAD displays the Startup dialog box as shown below.
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Figure 04: Startup dialogue box Imperial Starts a new drawing based on the Imperial measurement system. The default drawing boundary (the drawing limits) is 12× 9 inches. Metric Starts a new drawing based on the Metric measurement system. The default drawing boundary (the drawing limits) is 420× 297 millimeters. 1.6 Opening a Drawing File » Open from the Pull-down menu or icon from Standard tool bar. Then following Select file dialogue box will appear. There you can select the location of the file and open it.
Figure 05: Select file dialogue box
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1.7 Saving a Drawing File » Save/Save As… AutoCAD displays the save Drawing As standard file selection dialog box. Then you can select the exact file saving folder and enter the file name and save the drawing. 1.8 Closing a Drawing File » Close AutoCAD closes the current drawing; if there have been no changes since the drawing was last saved. If you have modified the drawing, AutoCAD prompts you to save or discard the changes. You can close a file that has been opened in Read-Only mode when you have not made any changes or willing to discard changes. To save changes to a read-only file, you must use the SAVEAS command.
Close all Window » Close All When you invoke this command, a message box is displayed for each unsaved drawing, in which you can save any changes to the drawing before closing it.
Quit/exit File » Quit/Exit Quits AutoCAD if there have been no changes in all opened drawing since the drawings were last saved. If the drawing has been modified, AutoCAD displays the Drawing modification dialog box to prompt you to save or discard the changes before quiting. 1.9 Giving Commands You can give commands in AutoCAD several ways. Following methods are the most frequently used methods. 1. By typing the commands on the Command prompt. This is located below the drawing area. 2. Through Pull-down Menu: you can select the command on Pull-down menu and just click on it to activate the command. 3. Through the Tool bars
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2.0 Basic Geometrical Shapes 2.1.1 Drawing of Lines
Draw » Line Line command allows you to create a line where the end points are specified by two-dimensional or three-dimensional co-ordinates. Command: _line Specify first point: Use one of the point fixing methods Specify next point or [Undo]: Use one of the point fixing methods Specify next point or [Undo]: Use one of the point fixing methods Specify next point or [Close/Undo]: Use one of the point fixing methods Specify next point or [Close/Undo]: Use one of the point fixing methods or Press
to terminate the command
Undo You can undo the most recently drawn line segments by entering the key U in specify next point: Prompt
Close Close option joints the very last point with the very first point in the series of line segments that you had drawn using the line command, thus forming a closed shape. Coordinate systems in AutoCAD All drawings are superimposed on an invisible grid, or coordinate system, with horizontal X-axis and a vertical Y-axis.
(5,6) (8,6)
(2,4)
(2,2)
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Absolute Co-ordinate System (x, y) To enter an absolute coordinate, specify a point by entering its X and Y values in the format X, Y. the following sequence of coordinates showing how to draw a triangle using absolute coordinates. 5,5
Command: _line Specify first point: 3, 3 Specify next point or [Undo]: 7, 3 Specify next point or [Undo]: 5, 5 Specify next point or [Close/Undo]: c
3,3
7,3
Relative Rectangular Co-ordinate System (@x distance, y distance) Use relative coordinates when you know the position of a point with respect to the previous point. The relative rectangular coordinate is represented in the following format.
@-2,0
Command: _line Specify first point: 2, 2
@0,4
Specify next point or [Undo]: @ 4, 0
@-2,0
Specify next point or [Undo]: @ 0, 4 Specify next point or [Close/Undo]: @ -2, 0
@0,-2
Specify next point or [Close/Undo]: @ 0, -2 Specify next point or [Close/Undo]: @ -2, 0 Specify next point or [Close/Undo]: c
2,2
@4,0
NB: Distance is measured +Ve towards right and up and it is measured –Ve towards left and down
Relative Polar Co-ordinate System (@ distance < angle) Polar coordinate system uses a distance and an angle with reference to the previous point to locate a point. Angles measured in anti-clock wise direction. The relative polar coordinate is represented in the following format: Command: _line Specify first point: 2, 3
@4<180
@4<90
Specify next point or [Undo]: @ 4< 0 Specify next point or [Undo]: @ 4< 90 Specify next point or [Close/Undo]: @ 4< 180 Specify next point or [Close/Undo]: c
2,3
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2.1.2 Drawing of Circles Draw » Circle » [options] You can create circles in several ways. The default method is to specify a center and radius. AutoCAD also provides 3 more methods to draw circles which are discussed below. Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: Use one of the points fixing methods or enter an option
Center, Radius / Center, Diameter This allows drawing a circle based on the center point and radius or diameter. Specify radius of circle or [Diameter]: Enter radius value or enter D for diameter option.
3 Points Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 3p Specify first point on circle: Use one of the points fixing methods Specify second point on circle: Use one of the points fixing methods Specify third point on circle: Use one of the points fixing methods
P3
P2 P1
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2 Points Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2p Specify first end point of circle's diameter: Use one of the points fixing methods Specify second end point of circle's diameter: Use one of the points fixing methods
P2
P1
Tangent, Tangent, Radius Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: ttr Specify point on object for first tangent of circle: select an object Specify point on object for second tangent of circle: select an object Specify radius of circle <1.0000>: Enter a value
Tangent objects
2.1.3 Drawing of Rectangles Draw » Rectangle Command: _rectang Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: Use one of the points fixing methods Specify other corner point or [Area/Dimensions/Rotation]: Use one of the points fixing methods
You can draw rectangles in several methods by invoking options within “[]” brackets. For example AutoCAD will facilitate to draw chamfered or fillet rectangles.
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Normal Rectangle
Fillet Rectangle
2008
Chamfered Rectangle
Rectangle with line width .2’
2.1.4 Drawing of Arcs Draw » Arc » [options] Arc command allows you to create an arc segment. Arcs created by AutoCAD are circular which form a part of a circle. There are different methods of creating an arc, as illustrated below. The default method is to specify the circumference with three points. Command: arc Specify start point of arc or [Center]: Use one of the points fixing methods Specify second point of arc or [Center/End]: Use one of the points fixing methods Specify end point of arc: Use one of the points fixing methods
End Point
Arc Direction
Tangent Direction
Start Point
You can draw arc by using various methods and the commands can invoke from menu tool bar as shown in above.
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2.1.5 Drawing of Ellipse Draw » Ellipse » [options] AutoCAD helps drawing a perfect ellipse or elliptical curve using this command. There are two different ways drawing an ellipse: 1. Define the full length of length of one axis and half length of other axis. 2. Define the center point of the ellipse ( the point where to axes intersect with each other) and half length of other two axes Command: _ellipse Specify axis endpoint of ellipse or [Arc/Center]: Use one of the points fixing methods Specify other endpoint of axis: Use one of the points fixing methods Specify distance to other axis or [Rotation]: Use one of the points fixing methods
Command: _ellipse Specify axis endpoint of ellipse or [Arc/Center]: c Specify center of ellipse: Use one of the points fixing methods Specify endpoint of axis: Use one of the points fixing methods Specify distance to other axis or [Rotation]: Use one of the points fixing methods P3
P1
P3
P2 Other Axis Distance
Ellipse by axis endpoints
P1 Other Axis Distance
P2
Ellipse by axis Centre
2.1.6 Drawing of Polygon Using Polygon command you can draw geometrical shapes with number of sides varying between 3 and 1024 also it creates a regular polygon. Command: _polygon Enter number of sides <4>: Enter a positive integer (3-1024) Specify center of polygon or [Edge]: Specify a point or enter e Enter an option [Inscribed in circle/Circumscribed about circle] : Enter I or C Specify radius of circle: Specify radius of the imaginary circle
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Inscribed in Circle Specifies the radius of a circle on which all vertices of the polygon lie
Circumscribed about Circle Specifies the distance from the center of the polygon to the midpoints of the edges of the polygon
When you select Edge option Defines a polygon by specifying the endpoints of the first edge Specify first endpoint of edge: Specify a point (1) Specify second endpoint of edge: Specify a point (2)
3.0 Supportive tools to construction 3.1 Drawing Limits Format » Drawing Limits The drawing limits are two-dimensional points in the world coordinate system that represent a lower-left limit and an upper-right limit. You cannot impose limits on the Z direction. Command: limits Reset Model space limits: Specify lower left corner or [ON/OFF] <0.0000, 0.0000>: Use one of the point fixing methods Specify upper right corner <12.0000, 9.0000>: Use one of the point fixing methods
3.2 Units Format » Units AutoCAD displays the drawing units dialog box. Then you can select an option according to your preference.
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3.2 DSettings Tools » Drafting Settings… This command provides some of the drawing aids to create the drawing at faster pace. When you invoke this command AutoCAD displays the Drafting Settings dialog box.
This dialog box contains four tabs but most important one is Object Snap tab for beginners. Object snaps constrain point specification to exact locations, such as midpoint or an intersection, on existing objects. Using object snaps, you can locate an exact position on an object without knowing the coordinate or by drawing construction lines.
3.2 Status Bar
3.2.1 S(AP SNAP command causes the crosshairs to move in an imaginary grid so that the crosshairs locked on the intersection of the grid. You can select snap option either clicking S(AP icon on status bar or by pressing F9 key. The snap spacing can be changed by changing the parameters of the snap option of Drafting Settings dialog box shown in above. Using the command SNAP also, you can select option.
3.2.2 GRID GRID command will allow you to display grid over your drawing area specified by the limits. The spacing can be changed by the “Drafting Settings” dialog box which displays when you right click on the GRID icon on the status bar. The GRID command can be enabled/disabled by clicking on the GRID icon or by pressing F7 key
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3.2.3 ORTHO ORTHO command is used with LINE command. It ensures all the lines are constructed orthogonal to the current snap grid. You can select ORTHO mode either clicking “ORTHO” button on the status bar or by pressing F8 key.
3.2.4 POLAR POLAR command allows you to select angle measurements when drawing. The increment angle can be changed by using “Drafting settings” dialog box. You can select POLAR mode either clicking “POLAR” button on the status bar or by pressing F10 key
3.2.5 OS(AP OSNAP command allows you to snap objects at to various points given under “Drafting settings”. You can select OS(AP mode either clicking “OSNAP” button on the status bar or by pressing F3 key.
4.0 Editing Commands 4.1 Selecting Objects To activate the editing command first you need to select the object. AutoCAD gives you several methods to select the objects some of the very important methods explained as follows. • By pointing – When “Select objects”, is prompted, a small square is appeared on the screen instead crosshairs. What you have to do is just give a mouse click on which the object to be selected. Then the object will be selected and appears in dashed lines.
Select A only
•
By a Window – If you reply with “W” then you will be asked to give two opposite corners of a window. Using this method you have to select the window such a way that the object is totally enclosed by the window.
Selects D & E
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By a crossing Window – If you reply with “U” then you will be asked to give two opposite corners of a window. Here, any object which enclosed or touched by the window will be selected.
Selects A,C,D,E
• • • • •
Remove – Suppose you want to remove an object while you are selecting the objects. Then you can remove that object by simply typing “R” and deselect the object by clicking on it. Add – After removing objects, you can return to select object prompt by typing “A” Fence – By typing “F” you can specify a fence. All the objects which crossed by the fence will be selected. The fence is specified by giving points. Undo - Deselect the last selected object Last – Selects the last object drawn.
4.2 ERASE Modify » Erase This allows you to remove the selected objects from the AutoCAD drawing. Command: _erase Select objects: Pick an object to delete Select objects: Pick an object or
to terminate the command
4.3 OOPS This command restores the objects which have been erased by last ERASE command. Command: oops
4.4 U(DO (cont+z) This command simply undoes the previously executed command. 4.5 REDO (cont+y) This command will activate after undo have been performed. 4.6 COPY Modify » Copy This command will enable user to create duplicates of the object without changing the original object. (Without changing the position, dimension, properties, etc)
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Command: _copy Select objects: Select object to copy Select objects: Specify base point or [Displacement]: Specify a base point Specify
second
point
or
<use
first
point
as
displacement>:
Specify
the
destination Specify second point or [Exit/Undo] <Exit>:
Copied objects
Base Point
4.7 MOVE Modify » Move This command will enable you to move selected objects after you specified the source and destination. Command: _move Select objects: Use one of the object selection method Select objects: Specify base point or [Displacement]: Use one of the points fixing method or displacement Specify second point or <use first point as displacement>: Use one of the points fixing method or press
4.8 ROTATE Modify ► Rotate In two dimensional drawings, ROTATE command is used to rotate the objects about a specified angle. Command: _rotate Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0 Select objects: Select the object Select objects: Specify base point: Select a base point Specify rotation angle or [Copy/Reference] <0>: Enter required angle
A
D
B
C Original Object
D
C
A
B
After rotating 90 deg
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4.9 MIRROR Modify ► Mirror At times we need to create objects that are symmetrical about a particular axis. In such cases MIRROR command comes in handy. Here you can either keep the original object or erase. Command: _mirror Select objects: Select the object Select objects: Specify first point of mirror line: Use one of the points fixing method Specify second point of mirror line: Use one of the points fixing method Erase source objects? [Yes/No]: choose your option or A A C
F
C
AB = Mirror Line Mirror Image = FGH
D
G
D
E
E
B Original Object
4.10 OFFSET
H B
Mirror Image and Original Object
Modify ► Offset Offset creates a new object at a specified distance from a existing object or through a specified point. The selected objects such as polygons, which are closed, might be get scaled up or down uniformly. Command: _offset Current settings: Erase source=No Layer=Source OFFSETGAPTYPE=0 Specify offset distance or [Through/Erase/Layer]: Specify a distance Select object to offset or [Exit/Undo] <Exit>: Pick the object to offset Specify point on side to offset or [Exit/Multiple/Undo] <Exit>: pick a point Select object to offset or [Exit/Undo] <Exit>:
4.11 BREAK Modify ► Break This command allows you to remove part of an object or break at a point. Command: _break Select object: select the object to be break Specify second break point or [First point]: f Specify first break point: Use one of the point fixing methods Specify second break point: Use one of the point fixing methods Faculty of Engineering, Galle, Sri Lanka
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P2
P1 Before break
After break
4.12 SCALE Modify ► Scale Scale command enlarges or reduces the selected objects in the X, Y and Z directions. Command: _scale Select objects: Use one of the object selecting method Select objects: Specify base point: Use one of the point fixing method Specify scale factor or [Copy/Reference] <1.0000>: Enter scale factor
Scale Factor 0.5
Original Object Scale Factor 2
4.13 ARRAY Modify ► Array… When you need to make multiply copies of an object ARRAY command comes in handy. After you invoke the command it displays array dialog box where you can set the number of rows, number of columns etc. Also it allows you to preview and modify the data set, prior to committing to the array. Command: array
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4.14 TRIM Modify ► Trim Using this command you can cut and erase objects (straight lines, arcs etc.) across the specified points on that objects. This is useful when you want to ensure one object touches with the other one. Command: _trim Current settings: Projection=UCS, Edge=None Select cutting edges... Select objects or <select all>: Use one of the object selection method Select objects: Select object to trim or shift-select to extend or [Fence/Crossing/Project/Edge/eRase/Undo]: Select the object to be trimmed
Objects to Trim
Cutting Edges
Before Trim
After Trim
4.15 EXTE(D Modify ► Extend EXTEND command elongates an object to a boundary. This command facilitates you to extend an object to a boundary defined by other objects. Command: _extend Current settings: Projection=UCS, Edge=None Select boundary edges... Select objects or <select all>: Use one of the object selection method Select objects: Select object to extend or shift-select to trim or [Fence/Crossing/Project/Edge/Undo]: Select object to be extend
4.16 STRETCH Modify ► Stretch Sometimes we encounter the situations where it is required to change the size of an object in one direction only. In such situations, AutoCAD provides a command called STRETCH which stretches or compresses the selected objects according to the user’s preference.
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Command: _stretch Select objects to stretch by crossing-window or crossing-polygon... Select objects: Select objects by any crossing object selection method Specify base point or [Displacement]: Use one of the points fixing method Specify second point or <use first point as displacement>: Use one of the points fixing method
4.17 FILLET Modify ► Fillet This command allows you to create rounded edges between two objects. When you invoking the fillet command you must remember to set the fillet radius by selecting the “Radius” option. Also you have to decide whether you trim the edges by selecting “Trim” option. Command: _fillet Current settings: Mode = TRIM, Radius = 2.0000 Select first object or [Undo/Polyline/Radius/Trim/Multiple]: Select first object Select second object or shift-select to apply corner: Select second object
4.18 CHAMFER Modify ► Chamfer This command is used to create bevel corners formed by two non parallel lines. Command: _chamfer (TRIM mode) Current chamfer Length = 2.0000, Angle = 60 Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: Select first object Select second line or shift-select to apply corner: Select second object
4.19 JOI( Modify ► Join This command helps you to join the individual segments of lines, arcs, elliptical arcs and splines into a single object. Joining a line P1
Command: _join Select source object: Select the first object (P1) Select lines to join to source: 1 found Select lines to join to source: Select the second object (P2) 1 line joined to source
Joining an arc Command: _join Select source object: Select the arc Select arcs to join to source or [cLose]: L Arc converted to a circle.
Before
P2
Before
Join After Join
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4.19 EXPLODE Modify ► Explode This command helps you to breaks a compound object into its component objects. Command: _explode Select objects: Select the object to be exploded Select objects:
4.21 LE(GTHE( Modify ► Lengthen This command can be used to check or change the length of an object. Command:LENGTHEN Select an object or [DElta/Percent/Total/DYnamic]: Select one option inside the square bracket to change the length
If you select an object without selecting any option AutoCAD show you the current length of that object or the included angle. To change the length or angle, you must select one of the options.
5.0 Display Control Commands 5.1 Zoom View ► Zoom ► [options] This command enlarges or reduces the view of the drawing. When we are working on a drawing it is always required to bring the area of our interest to focus on to the screen. Command: ZOOM Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object]: Enter an option Regenerating model.
Options All: Center: Dynamic: Extent: Previous: Scale: Window: window Object: Realtime:
This zooms to display the entire drawing in the current viewport Zooms to display a window defined by a center point and magnification value or height Zooms to display the generated portion of the drawing with a view box Zoom the current window to largest possible size to fill the screen Zooms to display the previous view Zooms the display at a specified scale factor Zooms to display an area specified by two diagonally opposite corner points of a rectangular Zooms to display one or more selected objects as large as possible The cursor changes to a magnifying glass with plus(+) and minus (-) signs
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5.2 PA( View ► Pan ►Real Time/ Point / Left / Right / Up / Down This command allows you to move the drawing without changing magnification or dimention Command: pan Press ESC or ENTER to exit, or right-click to display shortcut menu.
5.3 REGE( View ► Regen Regen regenerates the entire drawing and recomputes the screen coordinates for all objects. Regen command used to make curves smooth after zooming. If the REGENAUTO feature is enabled, regeneration will be performed automatically.
Before Regeneration
After Regeneration
6.0 Create and Manage annotation in AutoCAD 6.1 TEXT Draw ► Text ►Single Line Text Text conveys the meaningful information in your drawing. We use text for title blocks, to label parts of the drawing, to give specifications, or make annotations. You can format text as Command: _text Current text style: "Standard” Text height: 0.2000 Specify start point of text or [Justify/Style]: Use one of the point fixing methods or enter an option Specify height <0.2000>: Enter a positive value Specify rotation angle of text <0>: Enter an angle
Start point
6.2 MTEXT Draw ► Text ►Multiline Text… Text in the form of paragraphs, can be effectively generated in AutoCAD with this tool. The userspecified text boundary determines the width of the paragraph and the justification of text within the paragraph. Each multiline text object is a single object, regardless of the number of lines it contain.
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Command: _mtext Current text style: "Standard" Text height: 0.2000 Specify first corner: Use one of the point fixing methods Specify opposite corner or [Height/Justify/Line spacing/Rotation/Style/Width]: Use one of the point fixing methods or enter an option
After you specify the second corner, AutoCAD displays the Multiline Text Editor Dialog box. The Multiline Text Editor includes a Text formatting toolbar and a shortcut menu.
6.3 STYLE Format ► Text Style… STYLE command is used to create user defined text styles.
AutoCAD provides a default text style called STANDARD. Users can define their own text style by choosing a font from the listed font files and applying the desired effect such as width factor and oblique angle.
6.4 TABLE Draw ► Table… The TABLE command opens the insert table dialog box.
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7.0 Managing Properties of Objects 7.1 COLOR Format ► Color… AutoCAD displays the select color dialog box Command: COLOR
You can select any color from the color pallets
7.2 LI(ETYPE Format ► Linetype… AutoCAD gives you several number of standard line types, which are saved in a library. Normally a line type is a repeating pattern of dashes, dots and blank spaces. Using different line types enables you to show more information for the uses of your drawings. When you invoke the command Line Type Manager dialog box will appear and you can load line types by clicking on Load button. Also you can set each line type current by clicking on Current button of the Line Type Manager dialog box. Command: linetype
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7.3 LWEIGHT Format ► Lineweight… Generally line weights add width to your object both in your screen and paper when plotting. Using line weights when you draw objects you can create heavy and thin objects so that you can easily differentiate between each. When you invoke the command Lineweight Settings dialog box will appear. Then you can select which ever the line weight you want. Command: lweight
7.4 LAYER Format ► Layer… One of the very important features of AutoCAD is having the facility of using different layers in your drawing. It helps to draw more several complex drawings in a single drawing using layer properties and it highly save the time and also it give proper understanding for users. For example, you can draw your building structure in several layers, electrical wiring in another several layers, A/C system in any other layers etc. when you refer the drawing, you can refer each individually by disabling other relevant layers. There are several properties of layers, those are explained below. (ame:
you can assign a name to each layer to distinguish it from other layers. Name can be up to 31 characters
Color:
You can assign a color to your layer
Line type:
This can be defined as the nature of the line assigned to the layer.
Line weight: This gives width to your object Lock/Unlock: This feature is used to prevent the user from editing objects in the drawing. But these layers are visible in both screen and plot On/Off:
When a layer is off, it is invisible but it functions for certain functions ZOOM, PAN, etc. Layers that are off are not plotted.
Freeze/Thaw: This is similar to On/Off and used when you work with view ports. You can off some layers in some view ports and on those layers in other view ports.
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When you invoke the command Layer Properties Manager dialog box will appear. Then you can create layers according to your preferences.
8.0 Dimensioning Dimensioning is the process of adding measurement annotation to a drawing. AutoCAD provides many ways to dimension objects and many ways to format dimensions. Dimensions show the measurements of objects, the distances or angles between objects, or the distance of a feature from an origin specify. 8.1 DIMLI(EAR Dimension ► Linear Command: _dimlinear Specify first extension line origin or <select object>: Pick the first extension line origin or press enter to pick the object Specify second extension line origin: Pick the first extension line origin Specify dimension line location or [Mtext/Text/Angle/Horizontal/Vertical/Rotated]: Pick the location of dimension line or enter an option Dimension text = 7.4050
P1
P2
P3
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8.2 DIMALIG(ED Dimension ► Aligned Command: _dimaligned Specify first extension line origin or <select object>: Pick the first extension line origin or press enter to pick the object Specify second extension line origin: Pick the first extension line origin Specify dimension line location or [Mtext/Text/Angle]: Pick the location of dimension line or enter an option Dimension text = 1.4963
To activate the object selection option you have to press enter key.
P1 Object Selected
8.3 DIMRADIUS Dimension ► Radius A radial dimension consists of a radius dimension line with an arrowhead at the arc or circle end. Command: _dimradius Select arc or circle: Select the arc or circle which you need to have dimensioning Dimension text = 1.0000 Specify dimension line location or [Mtext/Text/Angle]: Pick the location of dimension line or enter an option
8.4 DIMDIAMETER Dimension ► Diameter DIMDIAMETER draws different types of diameter dimensions depending on the size of the circle or arc.
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8.5 DIMA(GULAR Dimension ► Angular Command: _dimangular Select arc, circle, line, or <specify vertex>: Select the object or vertex
8.6 DIMBASELI(E Dimension ► Baseline DIMBASELINE draws a series of related dimensions measured from the same baseline. AutoCAD offsets each new dimension line to avoid overlaying the previous dimension line. Command: _dimbaseline Specify a second extension line origin or [Undo/Select] <Select>: Pick the second extension line origin or press Dimension text = 1.3610
8.7 DIMCO(TI(UE Dimension ► Continue DIMCONTINUE draws a series of related dimensions, such as several shorter dimensions that add up to the total measurement. Continued dimensioning is also known as chain dimensioning. Command: _dimcontinue Specify a second extension line origin or [Undo/Select] <Select>: Pick the second extension line origin or press Dimension text = 2.4283
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DEVELOPMENT PROGRAMME AUTO CAD RPGD Rathnaweera
2008
FACULTY OF ENGINEERING,
GALLE, SRI LANKA
Development Programme
2008
Computer Aided Drafting using AutoCAD 1.0 CAD and AutoCAD Commonly, CAD stands for computer Aided Drafting which is used to produce technical drawings using a computer. Today with the development of computer industry, there are many types of software developed for computer Aided Drafting. AutoCAD is one of the leading and most popular software used in the industry.
1.1 Special Features of AutoCAD •
Gives greater accuracy compared to the traditional hand drafting methods
•
Automatic Dimensioning with customized tools
•
Layer Properties
•
Zooming of the Drawing or Part of the Drawing
•
Ability to attach textural information
1.2 Recommended Hardware List below are the hardware requirements for running AutoCAD 2007 on any system.
•
Pentium IV (800 MHZ) or higher
•
512 MB RAM
•
1024 X 768 VGA with true color
•
Installation 550 MB hard-disk space
•
Pointing device (Mouse)
•
CD-ROM Drive
•
Windows XP Professional / Windows 2000 with SP3 or SP4
1.3 The first look at AutoCAD Launching AutoCAD is very simple. Double-click the
shortcut icon or start the
application by clicking
Start » Programs » Autodesk » AutoCAD 2007 » AutoCAD 2007 After a few moments, you could see the AutoCAD 2007 interface as shown in the following figure.
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Properties Toolbar Title Bar
Standard Toolbar
Menu Bar Draw Toolbar Cross Hair
Drawing Area
UCS Icon Command Prompt Window
Scroll bars
Layout Tabs
Coordinate Display
Status Bar
Figure 01: Graphical user Interface (GUI) of AutoCAD 2007 1.4 The Pull-down Menus The Pull-down menus available on the menu bar offer a quicker way to access the commands and functions are the heart of AutoCAD 2007.
Figure 02: Pull-down menu Faculty of Engineering, Galle, Sri Lanka
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1.5 Creating a (ew Drawing When you start a new drawing, follow the following steps. File » (ew from the Pull-down menu or click on the
icon on the Standard toolbar.
Then following Select Template dialogue box will appear
Figure 03: Select Template Dialogue Box A drawing template file contains standard settings. You can select one of the template files supplied, or create your own template files. Drawing template files have a .dwt file extension. By default, drawing template files are stored in the template folder. For the starting, select “acad.dwt” template The behavior of the NEW command is determined by the Startup setting on the system tab of the options dialog box.
By default, “Do not show a startup dialog” option is selected in the system tab of the options dialog box. When you select the “show Startup dialog box” option, AutoCAD displays the Startup dialog box as shown below.
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Figure 04: Startup dialogue box Imperial Starts a new drawing based on the Imperial measurement system. The default drawing boundary (the drawing limits) is 12× 9 inches. Metric Starts a new drawing based on the Metric measurement system. The default drawing boundary (the drawing limits) is 420× 297 millimeters. 1.6 Opening a Drawing File » Open from the Pull-down menu or icon from Standard tool bar. Then following Select file dialogue box will appear. There you can select the location of the file and open it.
Figure 05: Select file dialogue box
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1.7 Saving a Drawing File » Save/Save As… AutoCAD displays the save Drawing As standard file selection dialog box. Then you can select the exact file saving folder and enter the file name and save the drawing. 1.8 Closing a Drawing File » Close AutoCAD closes the current drawing; if there have been no changes since the drawing was last saved. If you have modified the drawing, AutoCAD prompts you to save or discard the changes. You can close a file that has been opened in Read-Only mode when you have not made any changes or willing to discard changes. To save changes to a read-only file, you must use the SAVEAS command.
Close all Window » Close All When you invoke this command, a message box is displayed for each unsaved drawing, in which you can save any changes to the drawing before closing it.
Quit/exit File » Quit/Exit Quits AutoCAD if there have been no changes in all opened drawing since the drawings were last saved. If the drawing has been modified, AutoCAD displays the Drawing modification dialog box to prompt you to save or discard the changes before quiting. 1.9 Giving Commands You can give commands in AutoCAD several ways. Following methods are the most frequently used methods. 1. By typing the commands on the Command prompt. This is located below the drawing area. 2. Through Pull-down Menu: you can select the command on Pull-down menu and just click on it to activate the command. 3. Through the Tool bars
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2.0 Basic Geometrical Shapes 2.1.1 Drawing of Lines
Draw » Line Line command allows you to create a line where the end points are specified by two-dimensional or three-dimensional co-ordinates. Command: _line Specify first point: Use one of the point fixing methods Specify next point or [Undo]: Use one of the point fixing methods Specify next point or [Undo]: Use one of the point fixing methods Specify next point or [Close/Undo]: Use one of the point fixing methods Specify next point or [Close/Undo]: Use one of the point fixing methods or Press
to terminate the command
Undo You can undo the most recently drawn line segments by entering the key U in specify next point: Prompt
Close Close option joints the very last point with the very first point in the series of line segments that you had drawn using the line command, thus forming a closed shape. Coordinate systems in AutoCAD All drawings are superimposed on an invisible grid, or coordinate system, with horizontal X-axis and a vertical Y-axis.
(5,6) (8,6)
(2,4)
(2,2)
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Absolute Co-ordinate System (x, y) To enter an absolute coordinate, specify a point by entering its X and Y values in the format X, Y. the following sequence of coordinates showing how to draw a triangle using absolute coordinates. 5,5
Command: _line Specify first point: 3, 3 Specify next point or [Undo]: 7, 3 Specify next point or [Undo]: 5, 5 Specify next point or [Close/Undo]: c
3,3
7,3
Relative Rectangular Co-ordinate System (@x distance, y distance) Use relative coordinates when you know the position of a point with respect to the previous point. The relative rectangular coordinate is represented in the following format.
@-2,0
Command: _line Specify first point: 2, 2
@0,4
Specify next point or [Undo]: @ 4, 0
@-2,0
Specify next point or [Undo]: @ 0, 4 Specify next point or [Close/Undo]: @ -2, 0
@0,-2
Specify next point or [Close/Undo]: @ 0, -2 Specify next point or [Close/Undo]: @ -2, 0 Specify next point or [Close/Undo]: c
2,2
@4,0
NB: Distance is measured +Ve towards right and up and it is measured –Ve towards left and down
Relative Polar Co-ordinate System (@ distance < angle) Polar coordinate system uses a distance and an angle with reference to the previous point to locate a point. Angles measured in anti-clock wise direction. The relative polar coordinate is represented in the following format: Command: _line Specify first point: 2, 3
@4<180
@4<90
Specify next point or [Undo]: @ 4< 0 Specify next point or [Undo]: @ 4< 90 Specify next point or [Close/Undo]: @ 4< 180 Specify next point or [Close/Undo]: c
2,3
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2.1.2 Drawing of Circles Draw » Circle » [options] You can create circles in several ways. The default method is to specify a center and radius. AutoCAD also provides 3 more methods to draw circles which are discussed below. Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: Use one of the points fixing methods or enter an option
Center, Radius / Center, Diameter This allows drawing a circle based on the center point and radius or diameter. Specify radius of circle or [Diameter]: Enter radius value or enter D for diameter option.
3 Points Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 3p Specify first point on circle: Use one of the points fixing methods Specify second point on circle: Use one of the points fixing methods Specify third point on circle: Use one of the points fixing methods
P3
P2 P1
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2 Points Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2p Specify first end point of circle's diameter: Use one of the points fixing methods Specify second end point of circle's diameter: Use one of the points fixing methods
P2
P1
Tangent, Tangent, Radius Command: _circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: ttr Specify point on object for first tangent of circle: select an object Specify point on object for second tangent of circle: select an object Specify radius of circle <1.0000>: Enter a value
Tangent objects
2.1.3 Drawing of Rectangles Draw » Rectangle Command: _rectang Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: Use one of the points fixing methods Specify other corner point or [Area/Dimensions/Rotation]: Use one of the points fixing methods
You can draw rectangles in several methods by invoking options within “[]” brackets. For example AutoCAD will facilitate to draw chamfered or fillet rectangles.
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Normal Rectangle
Fillet Rectangle
2008
Chamfered Rectangle
Rectangle with line width .2’
2.1.4 Drawing of Arcs Draw » Arc » [options] Arc command allows you to create an arc segment. Arcs created by AutoCAD are circular which form a part of a circle. There are different methods of creating an arc, as illustrated below. The default method is to specify the circumference with three points. Command: arc Specify start point of arc or [Center]: Use one of the points fixing methods Specify second point of arc or [Center/End]: Use one of the points fixing methods Specify end point of arc: Use one of the points fixing methods
End Point
Arc Direction
Tangent Direction
Start Point
You can draw arc by using various methods and the commands can invoke from menu tool bar as shown in above.
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2.1.5 Drawing of Ellipse Draw » Ellipse » [options] AutoCAD helps drawing a perfect ellipse or elliptical curve using this command. There are two different ways drawing an ellipse: 1. Define the full length of length of one axis and half length of other axis. 2. Define the center point of the ellipse ( the point where to axes intersect with each other) and half length of other two axes Command: _ellipse Specify axis endpoint of ellipse or [Arc/Center]: Use one of the points fixing methods Specify other endpoint of axis: Use one of the points fixing methods Specify distance to other axis or [Rotation]: Use one of the points fixing methods
Command: _ellipse Specify axis endpoint of ellipse or [Arc/Center]: c Specify center of ellipse: Use one of the points fixing methods Specify endpoint of axis: Use one of the points fixing methods Specify distance to other axis or [Rotation]: Use one of the points fixing methods P3
P1
P3
P2 Other Axis Distance
Ellipse by axis endpoints
P1 Other Axis Distance
P2
Ellipse by axis Centre
2.1.6 Drawing of Polygon Using Polygon command you can draw geometrical shapes with number of sides varying between 3 and 1024 also it creates a regular polygon. Command: _polygon Enter number of sides <4>: Enter a positive integer (3-1024) Specify center of polygon or [Edge]: Specify a point or enter e Enter an option [Inscribed in circle/Circumscribed about circle] : Enter I or C Specify radius of circle: Specify radius of the imaginary circle
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Inscribed in Circle Specifies the radius of a circle on which all vertices of the polygon lie
Circumscribed about Circle Specifies the distance from the center of the polygon to the midpoints of the edges of the polygon
When you select Edge option Defines a polygon by specifying the endpoints of the first edge Specify first endpoint of edge: Specify a point (1) Specify second endpoint of edge: Specify a point (2)
3.0 Supportive tools to construction 3.1 Drawing Limits Format » Drawing Limits The drawing limits are two-dimensional points in the world coordinate system that represent a lower-left limit and an upper-right limit. You cannot impose limits on the Z direction. Command: limits Reset Model space limits: Specify lower left corner or [ON/OFF] <0.0000, 0.0000>: Use one of the point fixing methods Specify upper right corner <12.0000, 9.0000>: Use one of the point fixing methods
3.2 Units Format » Units AutoCAD displays the drawing units dialog box. Then you can select an option according to your preference.
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3.2 DSettings Tools » Drafting Settings… This command provides some of the drawing aids to create the drawing at faster pace. When you invoke this command AutoCAD displays the Drafting Settings dialog box.
This dialog box contains four tabs but most important one is Object Snap tab for beginners. Object snaps constrain point specification to exact locations, such as midpoint or an intersection, on existing objects. Using object snaps, you can locate an exact position on an object without knowing the coordinate or by drawing construction lines.
3.2 Status Bar
3.2.1 S(AP SNAP command causes the crosshairs to move in an imaginary grid so that the crosshairs locked on the intersection of the grid. You can select snap option either clicking S(AP icon on status bar or by pressing F9 key. The snap spacing can be changed by changing the parameters of the snap option of Drafting Settings dialog box shown in above. Using the command SNAP also, you can select option.
3.2.2 GRID GRID command will allow you to display grid over your drawing area specified by the limits. The spacing can be changed by the “Drafting Settings” dialog box which displays when you right click on the GRID icon on the status bar. The GRID command can be enabled/disabled by clicking on the GRID icon or by pressing F7 key
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3.2.3 ORTHO ORTHO command is used with LINE command. It ensures all the lines are constructed orthogonal to the current snap grid. You can select ORTHO mode either clicking “ORTHO” button on the status bar or by pressing F8 key.
3.2.4 POLAR POLAR command allows you to select angle measurements when drawing. The increment angle can be changed by using “Drafting settings” dialog box. You can select POLAR mode either clicking “POLAR” button on the status bar or by pressing F10 key
3.2.5 OS(AP OSNAP command allows you to snap objects at to various points given under “Drafting settings”. You can select OS(AP mode either clicking “OSNAP” button on the status bar or by pressing F3 key.
4.0 Editing Commands 4.1 Selecting Objects To activate the editing command first you need to select the object. AutoCAD gives you several methods to select the objects some of the very important methods explained as follows. • By pointing – When “Select objects”, is prompted, a small square is appeared on the screen instead crosshairs. What you have to do is just give a mouse click on which the object to be selected. Then the object will be selected and appears in dashed lines.
Select A only
•
By a Window – If you reply with “W” then you will be asked to give two opposite corners of a window. Using this method you have to select the window such a way that the object is totally enclosed by the window.
Selects D & E
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By a crossing Window – If you reply with “U” then you will be asked to give two opposite corners of a window. Here, any object which enclosed or touched by the window will be selected.
Selects A,C,D,E
• • • • •
Remove – Suppose you want to remove an object while you are selecting the objects. Then you can remove that object by simply typing “R” and deselect the object by clicking on it. Add – After removing objects, you can return to select object prompt by typing “A” Fence – By typing “F” you can specify a fence. All the objects which crossed by the fence will be selected. The fence is specified by giving points. Undo - Deselect the last selected object Last – Selects the last object drawn.
4.2 ERASE Modify » Erase This allows you to remove the selected objects from the AutoCAD drawing. Command: _erase Select objects: Pick an object to delete Select objects: Pick an object or
to terminate the command
4.3 OOPS This command restores the objects which have been erased by last ERASE command. Command: oops
4.4 U(DO (cont+z) This command simply undoes the previously executed command. 4.5 REDO (cont+y) This command will activate after undo have been performed. 4.6 COPY Modify » Copy This command will enable user to create duplicates of the object without changing the original object. (Without changing the position, dimension, properties, etc)
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Command: _copy Select objects: Select object to copy Select objects: Specify base point or [Displacement]
second
point
or
<use
first
point
as
displacement>:
Specify
the
destination Specify second point or [Exit/Undo] <Exit>:
Copied objects
Base Point
4.7 MOVE Modify » Move This command will enable you to move selected objects after you specified the source and destination. Command: _move Select objects: Use one of the object selection method Select objects: Specify base point or [Displacement]
4.8 ROTATE Modify ► Rotate In two dimensional drawings, ROTATE command is used to rotate the objects about a specified angle. Command: _rotate Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0 Select objects: Select the object Select objects: Specify base point: Select a base point Specify rotation angle or [Copy/Reference] <0>: Enter required angle
A
D
B
C Original Object
D
C
A
B
After rotating 90 deg
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4.9 MIRROR Modify ► Mirror At times we need to create objects that are symmetrical about a particular axis. In such cases MIRROR command comes in handy. Here you can either keep the original object or erase. Command: _mirror Select objects: Select the object Select objects: Specify first point of mirror line: Use one of the points fixing method Specify second point of mirror line: Use one of the points fixing method Erase source objects? [Yes/No]
F
C
AB = Mirror Line Mirror Image = FGH
D
G
D
E
E
B Original Object
4.10 OFFSET
H B
Mirror Image and Original Object
Modify ► Offset Offset creates a new object at a specified distance from a existing object or through a specified point. The selected objects such as polygons, which are closed, might be get scaled up or down uniformly. Command: _offset Current settings: Erase source=No Layer=Source OFFSETGAPTYPE=0 Specify offset distance or [Through/Erase/Layer]
4.11 BREAK Modify ► Break This command allows you to remove part of an object or break at a point. Command: _break Select object: select the object to be break Specify second break point or [First point]: f Specify first break point: Use one of the point fixing methods Specify second break point: Use one of the point fixing methods Faculty of Engineering, Galle, Sri Lanka
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P2
P1 Before break
After break
4.12 SCALE Modify ► Scale Scale command enlarges or reduces the selected objects in the X, Y and Z directions. Command: _scale Select objects: Use one of the object selecting method Select objects: Specify base point: Use one of the point fixing method Specify scale factor or [Copy/Reference] <1.0000>: Enter scale factor
Scale Factor 0.5
Original Object Scale Factor 2
4.13 ARRAY Modify ► Array… When you need to make multiply copies of an object ARRAY command comes in handy. After you invoke the command it displays array dialog box where you can set the number of rows, number of columns etc. Also it allows you to preview and modify the data set, prior to committing to the array. Command: array
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4.14 TRIM Modify ► Trim Using this command you can cut and erase objects (straight lines, arcs etc.) across the specified points on that objects. This is useful when you want to ensure one object touches with the other one. Command: _trim Current settings: Projection=UCS, Edge=None Select cutting edges... Select objects or <select all>: Use one of the object selection method Select objects: Select object to trim or shift-select to extend or [Fence/Crossing/Project/Edge/eRase/Undo]: Select the object to be trimmed
Objects to Trim
Cutting Edges
Before Trim
After Trim
4.15 EXTE(D Modify ► Extend EXTEND command elongates an object to a boundary. This command facilitates you to extend an object to a boundary defined by other objects. Command: _extend Current settings: Projection=UCS, Edge=None Select boundary edges... Select objects or <select all>: Use one of the object selection method Select objects: Select object to extend or shift-select to trim or [Fence/Crossing/Project/Edge/Undo]: Select object to be extend
4.16 STRETCH Modify ► Stretch Sometimes we encounter the situations where it is required to change the size of an object in one direction only. In such situations, AutoCAD provides a command called STRETCH which stretches or compresses the selected objects according to the user’s preference.
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Command: _stretch Select objects to stretch by crossing-window or crossing-polygon... Select objects: Select objects by any crossing object selection method Specify base point or [Displacement]
4.17 FILLET Modify ► Fillet This command allows you to create rounded edges between two objects. When you invoking the fillet command you must remember to set the fillet radius by selecting the “Radius” option. Also you have to decide whether you trim the edges by selecting “Trim” option. Command: _fillet Current settings: Mode = TRIM, Radius = 2.0000 Select first object or [Undo/Polyline/Radius/Trim/Multiple]: Select first object Select second object or shift-select to apply corner: Select second object
4.18 CHAMFER Modify ► Chamfer This command is used to create bevel corners formed by two non parallel lines. Command: _chamfer (TRIM mode) Current chamfer Length = 2.0000, Angle = 60 Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: Select first object Select second line or shift-select to apply corner: Select second object
4.19 JOI( Modify ► Join This command helps you to join the individual segments of lines, arcs, elliptical arcs and splines into a single object. Joining a line P1
Command: _join Select source object: Select the first object (P1) Select lines to join to source: 1 found Select lines to join to source: Select the second object (P2) 1 line joined to source
Joining an arc Command: _join Select source object: Select the arc Select arcs to join to source or [cLose]: L Arc converted to a circle.
Before
P2
Before
Join After Join
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4.19 EXPLODE Modify ► Explode This command helps you to breaks a compound object into its component objects. Command: _explode Select objects: Select the object to be exploded Select objects:
4.21 LE(GTHE( Modify ► Lengthen This command can be used to check or change the length of an object. Command:LENGTHEN Select an object or [DElta/Percent/Total/DYnamic]: Select one option inside the square bracket to change the length
If you select an object without selecting any option AutoCAD show you the current length of that object or the included angle. To change the length or angle, you must select one of the options.
5.0 Display Control Commands 5.1 Zoom View ► Zoom ► [options] This command enlarges or reduces the view of the drawing. When we are working on a drawing it is always required to bring the area of our interest to focus on to the screen. Command: ZOOM Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object]
Options All: Center: Dynamic: Extent: Previous: Scale: Window: window Object: Realtime:
This zooms to display the entire drawing in the current viewport Zooms to display a window defined by a center point and magnification value or height Zooms to display the generated portion of the drawing with a view box Zoom the current window to largest possible size to fill the screen Zooms to display the previous view Zooms the display at a specified scale factor Zooms to display an area specified by two diagonally opposite corner points of a rectangular Zooms to display one or more selected objects as large as possible The cursor changes to a magnifying glass with plus(+) and minus (-) signs
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5.2 PA( View ► Pan ►Real Time/ Point / Left / Right / Up / Down This command allows you to move the drawing without changing magnification or dimention Command: pan Press ESC or ENTER to exit, or right-click to display shortcut menu.
5.3 REGE( View ► Regen Regen regenerates the entire drawing and recomputes the screen coordinates for all objects. Regen command used to make curves smooth after zooming. If the REGENAUTO feature is enabled, regeneration will be performed automatically.
Before Regeneration
After Regeneration
6.0 Create and Manage annotation in AutoCAD 6.1 TEXT Draw ► Text ►Single Line Text Text conveys the meaningful information in your drawing. We use text for title blocks, to label parts of the drawing, to give specifications, or make annotations. You can format text as Command: _text Current text style: "Standard” Text height: 0.2000 Specify start point of text or [Justify/Style]: Use one of the point fixing methods or enter an option Specify height <0.2000>: Enter a positive value Specify rotation angle of text <0>: Enter an angle
Start point
6.2 MTEXT Draw ► Text ►Multiline Text… Text in the form of paragraphs, can be effectively generated in AutoCAD with this tool. The userspecified text boundary determines the width of the paragraph and the justification of text within the paragraph. Each multiline text object is a single object, regardless of the number of lines it contain.
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Command: _mtext Current text style: "Standard" Text height: 0.2000 Specify first corner: Use one of the point fixing methods Specify opposite corner or [Height/Justify/Line spacing/Rotation/Style/Width]: Use one of the point fixing methods or enter an option
After you specify the second corner, AutoCAD displays the Multiline Text Editor Dialog box. The Multiline Text Editor includes a Text formatting toolbar and a shortcut menu.
6.3 STYLE Format ► Text Style… STYLE command is used to create user defined text styles.
AutoCAD provides a default text style called STANDARD. Users can define their own text style by choosing a font from the listed font files and applying the desired effect such as width factor and oblique angle.
6.4 TABLE Draw ► Table… The TABLE command opens the insert table dialog box.
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7.0 Managing Properties of Objects 7.1 COLOR Format ► Color… AutoCAD displays the select color dialog box Command: COLOR
You can select any color from the color pallets
7.2 LI(ETYPE Format ► Linetype… AutoCAD gives you several number of standard line types, which are saved in a library. Normally a line type is a repeating pattern of dashes, dots and blank spaces. Using different line types enables you to show more information for the uses of your drawings. When you invoke the command Line Type Manager dialog box will appear and you can load line types by clicking on Load button. Also you can set each line type current by clicking on Current button of the Line Type Manager dialog box. Command: linetype
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7.3 LWEIGHT Format ► Lineweight… Generally line weights add width to your object both in your screen and paper when plotting. Using line weights when you draw objects you can create heavy and thin objects so that you can easily differentiate between each. When you invoke the command Lineweight Settings dialog box will appear. Then you can select which ever the line weight you want. Command: lweight
7.4 LAYER Format ► Layer… One of the very important features of AutoCAD is having the facility of using different layers in your drawing. It helps to draw more several complex drawings in a single drawing using layer properties and it highly save the time and also it give proper understanding for users. For example, you can draw your building structure in several layers, electrical wiring in another several layers, A/C system in any other layers etc. when you refer the drawing, you can refer each individually by disabling other relevant layers. There are several properties of layers, those are explained below. (ame:
you can assign a name to each layer to distinguish it from other layers. Name can be up to 31 characters
Color:
You can assign a color to your layer
Line type:
This can be defined as the nature of the line assigned to the layer.
Line weight: This gives width to your object Lock/Unlock: This feature is used to prevent the user from editing objects in the drawing. But these layers are visible in both screen and plot On/Off:
When a layer is off, it is invisible but it functions for certain functions ZOOM, PAN, etc. Layers that are off are not plotted.
Freeze/Thaw: This is similar to On/Off and used when you work with view ports. You can off some layers in some view ports and on those layers in other view ports.
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When you invoke the command Layer Properties Manager dialog box will appear. Then you can create layers according to your preferences.
8.0 Dimensioning Dimensioning is the process of adding measurement annotation to a drawing. AutoCAD provides many ways to dimension objects and many ways to format dimensions. Dimensions show the measurements of objects, the distances or angles between objects, or the distance of a feature from an origin specify. 8.1 DIMLI(EAR Dimension ► Linear Command: _dimlinear Specify first extension line origin or <select object>: Pick the first extension line origin or press enter to pick the object Specify second extension line origin: Pick the first extension line origin Specify dimension line location or [Mtext/Text/Angle/Horizontal/Vertical/Rotated]: Pick the location of dimension line or enter an option Dimension text = 7.4050
P1
P2
P3
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8.2 DIMALIG(ED Dimension ► Aligned Command: _dimaligned Specify first extension line origin or <select object>: Pick the first extension line origin or press enter to pick the object Specify second extension line origin: Pick the first extension line origin Specify dimension line location or [Mtext/Text/Angle]: Pick the location of dimension line or enter an option Dimension text = 1.4963
To activate the object selection option you have to press enter key.
P1 Object Selected
8.3 DIMRADIUS Dimension ► Radius A radial dimension consists of a radius dimension line with an arrowhead at the arc or circle end. Command: _dimradius Select arc or circle: Select the arc or circle which you need to have dimensioning Dimension text = 1.0000 Specify dimension line location or [Mtext/Text/Angle]: Pick the location of dimension line or enter an option
8.4 DIMDIAMETER Dimension ► Diameter DIMDIAMETER draws different types of diameter dimensions depending on the size of the circle or arc.
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8.5 DIMA(GULAR Dimension ► Angular Command: _dimangular Select arc, circle, line, or <specify vertex>: Select the object or vertex
8.6 DIMBASELI(E Dimension ► Baseline DIMBASELINE draws a series of related dimensions measured from the same baseline. AutoCAD offsets each new dimension line to avoid overlaying the previous dimension line. Command: _dimbaseline Specify a second extension line origin or [Undo/Select] <Select>: Pick the second extension line origin or press Dimension text = 1.3610
8.7 DIMCO(TI(UE Dimension ► Continue DIMCONTINUE draws a series of related dimensions, such as several shorter dimensions that add up to the total measurement. Continued dimensioning is also known as chain dimensioning. Command: _dimcontinue Specify a second extension line origin or [Undo/Select] <Select>: Pick the second extension line origin or press Dimension text = 2.4283
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Faculty of Engineering, Galle, Sri Lanka
2008
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