COMPUTER AIDED ELECTRICAL DRAWING

COMPUTER AIDED ELECTRICAL DRAWING Published by:

POLITEKNIK SULTAN HAJI AHMAD SHAH 25350 KUANTAN, PAHANG DARUL MAKMUR COPYRIGHT©2020, Politeknik Sultan Haji Ahmad Shah

Perpustakaan Negara Malaysia Cataloguing-in-Publication Data Wan Ghani Wan Pi, 1968COMPUTER AIDED ELECTRICAL DRAWING / WAN GHANI WAN PI, MOHD YUSOF ZAKARIA, TG BESARUDDIN SH TG YAAKOB. Mode of access: Internet eISBN 978-967-0778-67-9 1. AutoCAD--Handbooks, manuals, etc.

2. Computer-aided design--Handbooks, manuals, etc.

3. Government publications--Malaysia.

4. Electronic books.

I. Mohd. Yusof Zakaria, 1966-. II. Tg. Besaruddin Sh. Tg. Yaakob, 1966-.

III. Title.

620.00420285

Materials published in this book is under the copyright of the Politeknik Sultan Haji Ahmad Shah. All rights reserved. No part of this publication may be reproduced or distributed in any form of by means, electronic, mechanical, photocopying, recording, or otherwise or stored in a database or retrieval system without the prior written permission of the publisher.

Printed in Malaysia by: Xtreme Techno Trading No.6, Kg. Selamat Baru, Bangunan LKNP 25050 Kuantan Pahang Darul Makmur eISBN 978-967-0778-67-9

Computer Aided Electrical Drawing

PREFACE This book provides a step-by-step introduction to AutoCAD with commands presented in the context of each chapter. In eleven clear and comprehensive chapters, authors guide readers through all the important commands and techniques in AutoCAD 2018, for 2D drawing to complete electrical engineering schematics and finally finishing with plotting output. In each lesson, the author provides step-by-step instructions with frequent illustrations showing exactly what appears on the AutoCAD screen. Later, individual steps are no longer provided, and readers are asked to apply what they have learned by completing sequences on their own. A carefully developed pedagogy reinforces this cumulative-learning approach and supports readers in becoming skilled AutoCAD users. Tutorial Guide to AutoCAD 2018 begins with the Getting Started chapters that include information to get readers of all levels prepared for the tutorials.

The author includes tips that offer suggestions and warnings as you progress through the tutorials. Key Terms and Key Commands are listed at the end of each chapter to recap important topics and commands learned in each tutorial. Also, a glossary of terms and Commands Summary list the key commands used in the tutorials. Each chapter concludes with end of chapter tutorial providing challenges to a range of abilities in mechanical, electrical, and civil engineering as well as architectural problems.

Author: WAN GHANI BIN WAN PI Electrical Eng. Department, Kota Bharu Polytechnic, Kelantan Bachelor of Education (Hons) (Electrical Engineering) Autocad Certified Professional, Autodesk, USA HJ. MOHD YUSOF BIN ZAKARIA Director, Community College Kuantan, Pahang Bachelor of Education (Electrical Engineering) Autocad Certified Professional, Autodesk, USA TENGKU BESARUDDIN SHAH BIN TENGKU YAAKOB Mechanical Eng. Department, Sultan Haji Ahmad Shah Polytechnic Bachelor of Engineering (Hons.) Mechanical, DmechE. Autocad Certified Professional, Autodesk, USA

Computer Aided Electrical Drawing

Contents 01 INTRODUCTION OF AUTOCAD .......................................................................... 1 DEFINITION OF COMPUTER AIDED DESIGN (AUTOCAD) ................................. 1 DIFFERENCES BETWEEN AUTOCAD AND CONVENTIONAL DRAWING .......... 1 ADVANTAGES OF AUTOCAD OVER CONVENTIONAL TECHNICAL DRAWING 1 02 THE COMMANDS IN AUTOCAD ......................................................................... 2 KEYBOARD ............................................................................................................ 2 BUTTON MENU ...................................................................................................... 2 AutoCAD 2018 ICON MENU ................................................................................... 3 03 CREATING A NEW DRAWING ............................................................................. 6 SAVING A DRAWING ............................................................................................. 7 04 DRAWING SETUP ................................................................................................ 8 GRID AND SNAP .................................................................................................... 8 UNITS ..................................................................................................................... 9 The length options ................................................................................................ 9 LIMITS................................................................................................................... 10 05 DRAW COMMAND ............................................................................................. 12 LINE ...................................................................................................................... 12 Exercise 1 .......................................................................................................... 15 POLYLINE ............................................................................................................. 16 TEXT, DTEXT ( Dynamic text ) AND MTEXT (Multiline text) ................................ 18 Assignment 1b ................................................................................................... 21 CIRCLE ................................................................................................................. 22 ARC....................................................................................................................... 25 DONUT ................................................................................................................. 27 POLYGON ............................................................................................................ 28 Assignment 2 ..................................................................................................... 30 POINT ................................................................................................................... 34 Assignment 3a ( Electronic component ) ............................................................ 36 Assignment 3b ( Electrical parts ) ....................................................................... 37 06 MODIFY COMMAND .......................................................................................... 41 ERASE .................................................................................................................. 41 MOVE.................................................................................................................... 42 COPY .................................................................................................................... 43 ROTATE ................................................................................................................ 45 Computer Aided Electrical Drawing

BREAK .................................................................................................................. 46 TRIM ..................................................................................................................... 48 SCALE .................................................................................................................. 49 MIRROR ................................................................................................................ 51 ARRAY .................................................................................................................. 52 EXTEND................................................................................................................ 54 FILLET .................................................................................................................. 55 CHAMFER ............................................................................................................ 56 OFFSET ................................................................................................................ 58 CHANGE ............................................................................................................... 59 PEDIT.................................................................................................................... 59 OBJECT SNAPS ................................................................................................... 61 07 DISPLAY CONTROL ........................................................................................ 64 ZOOM ................................................................................................................ 64 ALL ..................................................................................................................... 65 CENTER ............................................................................................................ 65 DYNAMIC ........................................................................................................... 65 EXTENTS ........................................................................................................... 66 PREVIOUS ......................................................................................................... 66 SCALE (X/XP) .................................................................................................... 66 WINDOW ........................................................................................................... 67 PAN .................................................................................................................... 67 REDRAW ........................................................................................................... 68 REGEN .............................................................................................................. 68 08 BLOCK, WBLOCK AND INSERT BLOCK ........................................................ 69 BLOCK ............................................................................................................... 69 WBLOCK ( write block ) ..................................................................................... 71 INSERT BLOCK ................................................................................................. 72 MINSERT ........................................................................................................... 72 EXPLODE .......................................................................................................... 73 09 LAYER, LINETYPE AND COLOR .................................................................... 75 LAYER COMMANDS ......................................................................................... 75 HOW TO SET LINETYPES AND COLOR .......................................................... 78 10 DIMENSIONING............................................................................................... 81 IMPORTANCE AND BENEFITS OF DIMENSIONING DRAWINGS .................. 81 LINEAR .............................................................................................................. 83 RADIUS .............................................................................................................. 84 Computer Aided Electrical Drawing

DIAMETER ......................................................................................................... 84 ALIGNED ........................................................................................................... 85 ANGULAR .......................................................................................................... 85 DIM STYLE AND VARIABLE ............................................................................. 86 11 PLOTTING ....................................................................................................... 89 PREPARATORY STEPS FOR PLOTTING ........................................................ 89 PLOT AREA ....................................................................................................... 90 REFERENCES ......................................................................................................... 92

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01

INTRODUCTION OF AUTOCAD

DEFINITION OF COMPUTER AIDED DESIGN (AUTOCAD) AutoCAD is a computer aided drafting and design software from Autodesk Inc. It is widely used in various applications including all engineering fields.

DIFFERENCES BETWEEN AUTOCAD AND CONVENTIONAL DRAWING Using AutoCAD ❖ Designs can be made quickly. ❖ Designers only need to make a simple sketch of the design. ❖ Drawings produced are consistent and mistakes can be minimized. ❖ All angles of a drawing can be shown. ❖ Changes to drawing can be made easily. ❖ Exact copies of drawings can be produced quickly. ❖ Objects can be viewed in 3D. ❖ Objects can be viewed as animation.

ADVANTAGES OF AUTOCAD OVER CONVENTIONAL TECHNICAL DRAWING ❖ ❖ ❖ ❖ ❖

Improves the productivity, efficiency, and accuracy of drawings Enables drawings to be created, checked, and edited quickly Improves the quality of products Retains uniformity in reproduction Minimizes storage space

HARDWARE COMPONENTS OF THE AUTOCAD SYSTEM The hardware components of the AutoCAD system comprise the following : ❖ Monitor ❖ Central processing unit (CPU) ❖ Keyboard ❖ Mouse ❖ Plotter

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02

THE COMMANDS IN AUTOCAD

KEYBOARD Type in the command at the command line and press Enter or Space Bar.

Type here BUTTON MENU The menu is for a pointing device with multiple buttons. A point may be specified using a pointing device, such as a mouse or a digitizer puck. The coordinates of the selected point are then entered when the ‘PICK’ button of the pointing device is pressed.

Enter Pick or Select

Zoom

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AutoCAD 2018 ICON MENU Info Center

Panel Titles Application Menu Ribbon

Drawing Area

View Cube Navigation Bar

Crosshair

UCS

Command Line

Status Bar

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The buttons at the left-hand end of the status bar

A number of buttons at the left-hand end of the status bar can be used for toggling (turning on/off) various functions when operating within AutoCAD 2019. A click on a button turns that function on; if it is off, a click on a button turns the function back on.

Similar results can be obtained by using function keys of the computer keyboard (keys F1 to F10).

Snap Mode also toggled using the F9 key: when snap on, the cursor under mouse control can only be moved in jumps from one snap point to another.

Grid Display also toggled using the F7 key: when set on a series of grid points appears in the drawing area.

Ortho Mode also toggled using the F8 key: when set on, lines etc. can only be drawn vertically or horizontally.

Polar Tracking also toggled using the F10 key: when set on, a small tip appears Showing the direction and length of lines etc., in degrees and units.

Object Snap also toggled using the F3 key: when set on an OSnap icon appears at the cursor pick box.

Object Snap Tracking when setting on, lines etc., can be drawn at exact coordinate points and precise angles.

Allow/Disallow Dynamic UCS also toggled by the F6 key. Used when constructing 3D solid models.

Dynamic Input also toggled by F12. When set on, the x,y coordinates and prompts show when the cursor hairs are moved.

Show/Hide Lineweight when setting on, lineweights show on screen. When setting off, lineweights only show in plotted/printed drawings.

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Quick Properties a right-click brings up a pop-up menu, from which a click on Settings… causes the Drafting Settings dialog to appear.

The buttons at the right-hand end of the status bar Another set of buttons at the right-hand end of the status bar is shown below. The uses of some of these will become apparent when reading future pages of this book.

A click on the downward- facing arrow near the right-hand end of this set of buttons brings up the Application Status Bar Menu from which the buttons in the status bar can be set on or off.

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03

CREATING A NEW DRAWING

AutoCAD and AutoCAD LT create a blank drawing upon startup, but it’s a good idea to select the drawing template that you want to use at startup and not rely on the one that AutoCAD or AutoCAD LT creates for you. To create a new drawing, follow these steps:

1. Click Start Drawing.

For new drawing, click Start Drawing

A new drawing is created for you based on the drawing template selected.

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SAVING A DRAWING Before going further, it is as well to know how to save the drawings constructed when answering examples and exercises in this book. When a drawing has been constructed, left click on the Save icon Standard Annotation toolbar. The Save Drawing As dialog appears.

Unless you are the only person to use the computer on which the drawing has been constructed, it is best to save work to a pen drive, usually held in the drive E: To save a drawing to a pen drive in drive E:

1.

Place a pen drive in drive E:

2.

In the Save in field of the dialog, click the arrow to the right of the field and from the pop-up list drive [E:].

3.

In the File name: field of the type a name. The file name extension “.dwg” does not need to be typed – it will be added to the file name.

4.

Left click the Save button of the dialog. The drawing will be saved with the file name extension .dwg – the AutoCAD fi le name extension.

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04

DRAWING SETUP

GRID AND SNAP 1.

On the status bar, pick snap settings.

2.

The Drafting Settings dialog box appears below.

3.

Select the Snap On (F9) and Grid On (F7) options.

4.

In the Snap Spacing area, select Equal X and Y Spacing if it’s not selected.

5.

In the Snap Spacing area, double-click the Snap X Spacing text box, and then type 1 and press Tab. Because you selected the Equal X and Y Spacing option, the value in the Snap Y Spacing text box was updated to match the value entered in the Snap X Spacing text box.

6.

In the Grid Spacing area, double-click the Grid X Spacing text box, and then type 1 and press Tab. The value in the Grid Y Spacing text box is updated to match the value in the Grid X Spacing text box.

7.

In the Snap Type area, select Grid Snap and then select Rectangular Snap if they are not already selected.

8.

Click OK.

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UNITS There are two methods of doing this.

1. Type Units at the command prompt. OR 2. Click FORMAT

UNITS from the Pull-down menu (Autocad Classic ).

The length options Feet, inches, and fractional inches, as in 12´6.˝. You would enter

Architectural

this as 12´6 1/2˝ with a space between the 6 and the

1/2.

Feet and decimal inches, as in 12.5´ or 12´6.5˝. You would enter

Engineering

this as 12´6.5˝.

Decimal

Whole and decimal units that can be anything (metric distances, decimal inches, decimal feet, or decimal miles, for example).

Fractional

Whole and fractional units that can be anything (fractional metric distances, fractional inches, feet, or miles, for example).

Scientific

Scientific notation for distances. Units can be anything (meters, angstroms, miles, astronomic units, parsecs, or light-years, for example)

The angle options: Decimal

Degrees Whole and decimal degrees of angle. Deg/Min/Sec Degrees, minutes, and seconds of angle.

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Grads

Angles specified in grads. For example, you would specify 45° of an angle by entering 50g.

Radians

Angles specified in radians. For example, you would specify 45° by entering 0.785r.

Surveyor’s

Angles specified in degrees from north or south to east or west, as in Units N45dE.

Precision

The Precision option lets you control how AutoCAD reports length and angle values. This option does not actually affect the precision of the objects in the drawing. For example, if you select Decimal as the length type and 0.0 for the precision, AutoCAD displays a distance of 1.2 for the true distance of 1.167. If you choose 0.000 for the Precision option, you will see the full distance of 1.167 whenever AutoCAD displays a distance.

Direction

By default, AutoCAD assumes that 0° is a horizontal direction from left to right. For example, 90° is directly vertical, and 180° is a horizontal direction from right to left. Angle values increase from 0° in a counterclockwise fashion. The cardinal directions and their degree values in a default AutoCAD setup. If your drawing requires a different direction for 0°, you can use the Direction option to choose an angle. When you click the Direction button, the Direction Control dialog box opens. Click one of four radio buttons to select the 0° direction from the four cardinal directions.

If your desired 0° direction does not conform to the cardinal directions, you can specify an angle numerically or graphically by selecting the other option.

Clockwise

By default, angle values increase counterclockwise, but you can change this to clockwise by selecting the Clockwise option in the Angle group of the Drawing Units dialog box.

LIMITS There are two methods of doing this.

1. Type Limits at the command prompt. OR 2. Click FORMAT

LIMITS from the Pull-down menu (Autocad Classic ).

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The sample of paper size (0,420)

594mm

(0,297)

420mm

( 594,420 ) ( 420,297 )

A2

Upper right corner (0,210)

297mm

( 297,210 )

A3 297mm 420mm

A4

210mm

( 0, 0 ) ( 297,0 )

( 420,0 )

( 594,0 )

Lower left corner Example 1 : Command: limits Reset Model space limits: Specify lower left corner or [ON/OFF] <0.0,0.0>: 0.0 Specify upper right corner <0.0,0.0>: 420,297

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05

DRAW COMMAND

LINE The line is the most fundamental drawing entity. It can be drawn with various linetypes.

There are two methods of doing this.

3. Type Line or just L at the command prompt Or 4. Click Line from the Draw icon.

specify first point : Specify next point or [Undo] : Once a command has been entered, in many instances, AutoCAD requires additional input. The input may be in the form of coordinates, numeric value, displacements, modifiers, file names, etc. The following are four methods in which data that are points may be entered.

NOTE: Dynamic Input ( F12) OFF

1.0

Absolute Coordinate A point can be specified by typing the X and Y coordinates.

Example : Command : Line

60,120

160,120

first point : 60,60 next point : 160,60

60

next point : 160,120 next point : 60,120 next point : 60,60 @ c

60,60

100

160,60

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2.0

Relative Coordinate A point can be specified as the distance from the last coordinate entered. Type @ prior to the X and Y distances. @ means with reference to the last point.

Format : @ X distance, Y distance Y distance

X distance

Example : Command : Line

@-100,0

@0,60

first point : 60,130 next point : @100,0 next point : @0,60

60

next point : @-100,0 next point : 60,130 @ c

3.0

60,130

100

@100,0

Polar Coordinate

A point may be specified as the distance and the angle from the last coordinate (point) entered.

90o 180 o

0o 270 o @-90 o

format : @ distance < angle Example : Command : Line

@100<180

@60<90

first point : 60,200 next point : @100<0 next point : @60<90

60

next point : @100<180 next point : @60<270

60,200

100

@100<0 Computer Aided Electrical Drawing

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4.0

Pointing You may type the line coordinates using the keyboard or click the first point using the mouse.

•

Click any point in the drawing area. AutoCAD prompt specifies the next point or [Undo].

•

Move the mouse pointer to a second point and click button 1 of the mouse and enter.

First point

( go to page 40 – Erase command )

Second point

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Exercise 1 By using point entry commands, using Line Commands to draw the following figures:

38

60

20

50 30 O

3 0

60

8 0

27 200,16 0 10 00

43

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POLYLINE A polyline is a connected sequence of line segments created as a single object. You can create straight Line segments, Arc segments, or a combination of the two.

There are two methods of doing this.

1. Type Pline or just PL at the command prompt Or 2. From the Draw icon, choose the Polyline.

Specify start point :

Arc endpoint of arc:

Halfwidth

Length

starting half-width:

length of line:

ending half-width:

Undo

Width

Starting Width:

Ending width:

Specify next point :

Ending width Half-width Endpoint of Arc

Specify first point

Length of line

Starting Width

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Example 1 : Command : Pline Specify start point : 60,60 Specify next point or ( arc/halfwidth/length/undo/width) : w Starting width : 2 Ending width : 2 Specify next point or ( arc/halfwidth/length/undo/width) : @100<0 Specify next point or ( arc/halfwidth/length/undo/width) : @60<90 Specify next point or ( arc/halfwidth/length/undo/width) : @100<180 Specify next point or ( arc/halfwidth/length/undo/width) : close @100<180

@60<90

60

Example 2 :

60,60

100

@100<0

Command : Pline Specify start point : 60,130 Specify next point or ( arc/halfwidth/length/undo/width) : w Starting width : 10 Ending width : 10 Specify next point or ( arc/halfwidth/length/undo/width) : @50<0 Specify next point or ( arc/halfwidth/length/undo/width) : w Starting width : 15 Ending width : 0 Specify next point or ( arc/halfwidth/length/undo/width) : @20<0 Width=10

15 60,130

50

20

( go to page 62,65 – Zoom and Pan command )

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Assignment 1a Draw the block name below with DRAW and POLYLINE command by using all the coordinates. This block name using A3 size ( 420 mm x 297 mm ).

TEXT, DTEXT ( Dynamic text ) AND MTEXT (Multiline text) Computer Aided Electrical Drawing

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Single-line text is created with the DTEXT command. TEXT is now an alias for the DTEXT command; typing either at the command line runs DTEXT. You can define a few properties such as a single font or a preset height in a text style, but MTEXT can formatting multiline text, changing things such as font, size, and color, and structuring text in columns.

Mtext

Text/Dtext

Style

Style

Formatting

Paragraph

Insert

Options

Justify

Align

Fit

Center

Middle

Right

1st point

1st point

Center pt

Middle pt

Right Endpt

2nd point

2nd point

( go to page 41 & 42 – Move & Copy command ) Example 1 : Command: _mtext Computer Aided Electrical Drawing

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Specify first corner: pick first corner Specify opposite corner or [Height/Justify/Line spacing/Rotation/Style/Width/Columns]:

First corner

type text here

Example 2 : Command: text Current text style: "Standard" Text height: 3.0 Annotative: No Specify start point of text or [Justify/Style]: pick a start point Specify height <0>: 5 Specify rotation angle of text <0>: 0 Height = 5

AUTOCAD

ROTATION = 0

Start point ( go to page 58 – Pedit command )

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Assignment 1b Use Text or Dtext or Mtext command to fill all the text at the block name ( open an existing drawing Assignment 1 ) with the related size of the text shown below.

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CIRCLE A circle can be drawn with various linetypes.

There are two methods of doing this.

1. Type Circle or just C at the command prompt OR 2. Click Circle from the Draw icon

Center point

Radius

Diameter

3P

2P

TTR

TTT

1st point

1st point

1st tangent spec

1st Tangent

2nd point

2nd point

2nd tangent spec

2nd Tangent

Radius

3rd Tangent

3rd point

TTR

2P

TTT

3P

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Example 1 : Command: Circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]:100,100 Specify radius of circle or [Diameter] <0.0000>: 30

Radius =30

Example 2 : Command: Circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]:100,170 Specify radius of circle or [Diameter] <0.0>: D Specify diameter of circle <0.0>: 60

Diameter =60

Example 3 : Command: Circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 3P Specify the first point on the circle: 170,130

1st Point X

Specify the second point on circle: 170,70 2 nd Point X

Specify the third point on circle: 200,100

3rd Point X

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Example 4 : Command: Circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2P Specify the first point on the circle: 170,200 Specify the second point on circle: 170,140 1st point x

x 2nd point Example 5 : Command: Circle Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: type TTR or T Specify point on object for first tangent of circle : ( select 1st tangent spec ) Specify point on object for second tangent of circle : (select 2nd tangent spec ) Specify radius of circle <0.0> : 30

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( go to page 60 – Object Snaps commands, go to page 66- Redraw & Regen command ) ARC The Arc is a partial circle that can be drawn using any of the different options in the pull down menu. It can also be drawn with various linetypes.

There are two methods of doing this.

1. Type Arc or just A at the command prompt OR 2. Click Arc from the Draw toolbar.

R

S – Start point

A - Angle

C – Center

L – Length of chord

E – End

R – Radius of the arc

D – Direction

3 point

SCE

SCA

SCL

SEA

SED

SER

CSE

CSA

CSL

1st point

Start

Start

Start

Start

Start

Start

Center

Center

Center

2nd point

Center

Center

Center

End

End

End

Start

Start

Start

3rd point

End

Angle

Length

Angle

Directio n

Radiu s

End

Angle

Length

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Example 1 :

Command : Arc ( 3 Point )

70,150

Specify start point of arc or [Center]: 100,70 Specify second point of arc or [Center/End]: 130,120 130,120 Specify end point of arc: 70,150

100,70 Example 2 :

Command: Arc ( Start, Center, Angle ) Specify start point of arc: 230,100 Specify center point of arc: @80<0 Specify included angle: -90

90 230,100 80

( go to page 44 – Rotate command )

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DONUT

The DONUT command is used to create a thick or solid circle. The inside diameter is used to determine the hole of the doughnut. Use an inside diameter of zero to create a solid circle; use a larger diameter to create a ring.

There are two methods of doing this.

1. Type Donut or just type DO at the command prompt OR 2. Click Donut from the Draw toolbar.

Donut Inside diameter :

Outside diameter : Center of donut

Example 1:

Command: Donut

30

Specify inside diameter of donut: 30 Specify outside diameter of donut: 40 Specify center of donut: 100,100

40

100,100

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Example 2:

Command: Donut Specify inside diameter of donut : 0 Specify outside diameter of donut: 40 Specify center of donut: 100,150

40

100,150

POLYGON

A polygon is a polyline object. AutoCAD draws polyline with zero width and no tangent information. Creating polygons is a simple way to draw squares, equilateral triangles, octagons and so on.

There are two methods of doing this.

1. Type Polygon or POL at the command prompt OR

2. From the Draw toolbar, choose the Polygon flyout.

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Triangle

Square Pentagon Hexagon

The number of sides of the polygon, for example, pentagon = 6, hexagon = 5 and etc.

In the first two illustrations, the center of Polygon and defines the radius length, which is specified with the pointing device or coordinate.

Example 1: Command: _polygon Enter number of sides: 6 Specify center of polygon or [Edge]: 120,100 Enter an option [Inscribed in circle/Circumscribed about circle] <C>: I Specify radius of circle: 40

Example 2: Command: _polygon Enter number of sides : 6 Specify center of polygon or [Edge]: 240,100 Enter an option [Inscribed in circle/Circumscribed about circle] <I> : C Specify radius of circle: 40 ( go to page 45 & 47 – Break & Trim command )

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Assignment 2

`

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ELLIPSE 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.

There are two methods of doing this.

1. Type Ellipse or type EL at the command prompt.

2. From the Draw icon, choose the Ellipse flyout.

Center

Axis/End

Elliptical Arc

Specify center

Specify axis endpoint

Specify axis endpoint

Specify endpoint

Specify other endpoint

Specify other endpoint

Specify distance

Specify distance

Specify distance Specify start angle Specify end angle

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Example 1: Command: _ellipse ( Center ) Specify center of ellipse: 100,150 Specify endpoint of axis: 150,190 Specify distance to other axis or [Rotation]: 20

Example 2:

Command: _ellipse ( Axis/End ) Specify axis endpoint of ellipse or [Arc/Center]: 260,190 Specify other endpoint of axis: 205,190 Specify distance to other axis or [Rotation]: 30

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Example 3: Command: _ellipse ( Arc ) Specify axis endpoint of elliptical arc or [Center]: 300,130 Specify other endpoint of axis: 350,130 Specify distance to other axis or [Rotation]: 50 Specify start angle or [Parameter]: -90 Specify end angle or [Parameter/Included angle]: 90

Start angle = -90 @ 270 and end angle = 90 is clockwise Start angle = 90 and end angle = -90 @ 270 is anti-clockwise

( go to page 48,50, 51 & 53 – Scale, Mirror, Array and Extend command ) Computer Aided Electrical Drawing

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POINT Point objects are useful as nodes or reference points. They are temporary objects you create to help you draw accurately.

There are two methods of doing this.

1. Type Point at the command prompt.

2. From the Draw icon, choose the Point flyout.

Point

Multiple Point

Devide

Measure

Specify a point

Select object

Select object

number of segments

length of segment

Line

You can set the style of the points and their size relative to the screen or in absolute units. Changing the style of points: ❖ Makes them more visible and easier to differentiate from grid dots ❖ Affects the display of all point objects in the drawing ❖ Requires using REGEN to make the change visible

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To set point style and size : 1. From the Home Tab, Utility group, 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 origin absolute units.

4. Choose OK.

Example 1 :

point style

Command: point Current point modes: PDMODE=4 PDSIZE=20.0 Specify a point: select point, select point 2 ( to stop press esc )

Example 2 : Command: divide

number of segments = 4

Select object to divide: pick Enter the number of segments or [Block]: 4

Example 3 : Command: measure Select object to measure: Specify length of segment or [Block]: 20 20

20

( go to page 54, 55, 57 & 58 – Fillet, Chamfer, Offset and Change command )

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Assignment 3a ( Electronic component ) By using all commands, draw all the components below and use an existing drawing name: Assignment 1a.

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Assignment 3b ( Electrical parts ) By using all commands, draw all the electrical parts below and use an existing drawing name: Assignment 1a.

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Legend

Electronic components

Electrical parts

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06

MODIFY COMMAND

ERASE

There are many ways to delete objects from your drawing and clean up the display There are two methods of doing this.

1.

Type Erase or just E at the command prompt.

2.

Click Erase from the Modify icon.

ERASE Select object : Pick object or select by window

Example 1

:

Command : erase Select objects: pick object and press Enter (when you finish selecting objects)

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MOVE The Move command allows one or more entities to be moved to any location in the drawing.

There are two methods of doing this.

1.

Type Move or just M at the command prompt.

2.

Click Move from the Modify toolbar.

MOVE Select object : Base point or displacement : pick point or type coordinate Second point of displacement : pick point or type coordinate

Example 1 : Command: Move Select objects: pick object Base point or displacement : (select center of circle ) Second point of displacement: @10<0 or pick point at drawing area

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COPY The Copy command allows you to make a copy or copies of an entity or a group at any location in the drawing.

There are two methods of doing this.

1. Type Copy or just Co at the command prompt.

2. Click Copy Object from the Modify icon.

COPY Select object :

Single copy

Multiple copy

Select object :

Select object :

Base point or displacement: Second point of displacement:

Base point or displacement: Second point of displacement: Second point of displacement: Second point of displacement:

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Example 1 : Command: copy Select objects: pick object Current settings: Copy mode = Multiple Specify base point or displacement : select CENter (OSNAP) Specify second point or <use first point as displacement>: @10<0 Specify second point or [Exit/Undo] <Exit>:

Example 2 : Command: copy Select objects: pick object Current settings: Copy mode = Multiple Specify base point or displcement: select CENter ( OSNAP) Specify second point : @10<0 (copy 1) Specify second point or [Exit/Undo] <Exit>: @10,5 ( copy 2) Specify second point or [Exit/Undo] <Exit>: @10,-5 (copy 3)

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ROTATE The rotate command changes the orientation of existing entities by rotating them about a specified base point. The rotation angle may be given as a numeric value or by dragging the entity.

There are two methods of doing this.

1. Type Rotate or just Ro at the command prompt.

2. Click Rotate from the Modify icon.

ROTATE Select object :

Select base point: Rotation angle:

Example 1 :

Command : Rotate Select objects : pick object Base point : select base point <Rotation angle>/ Reference : 90 ( rotate 1) or <Rotation angle>/ Reference : -90 ( rotate 2)

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BREAK

The Break command is a convenient way to create a gap in an object, resulting in two objects with a space between them. Break is often used to create space for block or text insertion.

There are two methods of doing this.

1. Type Break or just Br at the command prompt.

2. Click Break from the Modify icon.

BREAK Select object : Second break point or [First point]

First point or type F First point: pick point Second point: pick 2nd point

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When breaking an object, you can either a) select the object at the first break point and then specify a second break point, or b) select the entire object and then specify two break points.

Example 1 : Command: Break Select the object to break: select P1 Specify the second object: @10<0

Example 2 : Command: Break Select the object to break: pick line Specify second break point or [First point]: f Specify first break point: select P1 Specify second break point: @10<0 Example 3 : Command: Break Select the object to break: pick P1 (QUAdrant) Computer Aided Electrical Drawing

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Specify second break point or [First point]: Pick P2 (QUAdrant)

Example 4 : Command: Break Select the object to break: pick P1 (QUAdrant) Specify second break point or [First point]: Pick P2 (QUAdrant)

TRIM The Trim command trims existing entities so that they end precisely at the cutting edge(s). The cutting edges can be Lines, Arcs, Circles, open 2D polylines There are two methods of doing this. Click Trim from the Modify icon.

1. Type Trim or just tr at the command prompt.

TRIM Select cutting edges: pick 2 or more cutting edges Select object to trim: pick 1 or more object to trim

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Example 1 : Command : Trim Select cutting edge : pick line ( cutting edges) <Select object to trim>/ Project / Edge / Undo : pick line or cicle ( trim object)

SCALE The Scale command enlarges or reduces selected objects equally in X and Y directions. Entities can be enlarged if a scale factor greater than 1 is selected and can be reduced in size if a scale factor between zero and 1 is selected.

There are two methods of doing this.

1.

Type Scale or just sc at the command prompt.

2.

Click Scale from the Modify toolbar.

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SCALE Select object: Select base point: Specify scale factor or [Copy/Reference]:

Scale factor:

Copy: Scale factor:

Reference: Specify reference length: Specify new length:

Example 1 : Command: scale Select objects: pick original object Specify base point: pick base point Specify scale factor or [Copy/Reference] <1>: 2 or Specify scale factor or [Copy/Reference] <1>: 0.5

Example 2 : Command: scale Select objects: pick original object Specify base point: pick base point Specify scale factor or [Copy/Reference] <1>: r Specify reference length <1>: 2 Specify new length or [Points] <3>: 10

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MIRROR

The Mirror command creates mirror images of the existing object about a mirror line.

Then the original object may either be retained or deleted.

There are two methods of doing this.

1. Type Mirror or just Mi at the command prompt.

2. Click Mirror from the Modify toolbar.

MIRROR Select object: 1st Point of Mirror Line: 2nd Point of Mirror Line:

Example 1 : Command: mirror Select objects: Specify opposite corner: 5 found Select objects: select the original object Specify first point of mirror line: pick mirror point Specify second point of mirror line: 180 Erase source objects? [Yes/No] <N>:

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ARRAY The Array command is used to make multiple copies of one or more objects in a rectangular (rows and colums) or polar (circular) pattern.

There are two methods of doing this.

1. Type Array or just Ar from the command prompt.

2. Click Array from the Modify toolbar.

Rectangular Array

Example 1 : Command: ARRAY Select objects: pick original object Enter array type [Rectangular/PAth/POlar] <Rectangular>: R number of items or [Base point/Angle/Count] <Count>: C Enter number of rows or [Expression] <4>: 3 Enter number of columns or [Expression] <4>: 2 Specify opposite corner to space items or [Spacing] <Spacing>: S Specify the distance between rows or [Expression] : 20 Specify the distance between columns or [Expression] : 15 Accept or [ASsociative/Base point/Rows/Columns/Levels/eXit]<eXit>: X

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Polar Array

Example 3 : Command: Array Select object s : pick original object Enter array type [Rectangular/PAth/POlar] <Rectangular>: PO Specify center point of array or [Base point/Axis of rotation]: pick center point Enter number of items or [Angle between/Expression] : 8 Specify the angle to fill (+=ccw, -=cw) or [EXpression] : 180 Accept or [ASsociative/Base point/Items/Angle between/Fill angle/ROWs/Levels/ROTate items/eXit]<eXit>: X

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EXTEND The Extend command lengthens existing entities so that they end precisely at the boundary edge(s). The boundary edges can be lines, arcs, circles or 2D polylines. The entities that can be extended are lines, arcs and open 2D polylines.

There are two methods of doing this.

1. Type Extend or just Ex at the command prompt.

2. Click Extend from the Modify toolbar.

EXTEND Select boundary edges: Select object to extend:

Example 1: Command: Extend Select boundary edges: pick boundary edge Select objects: pick line to extend

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FILLET The Fillet command connects two lines, arcs or circles with a smooth arc of a specified radius. The value for the radius may be entered numerically or shown as the distance between two points. The value of “0” for the radius results in a square corner.

There are two methods of doing this.

1.

Type Fillet or just F at the command prompt.

2. Click Fillet from the Modify toolbar.

FILLET

Trim

Select first object:

Radius Fillet radius

Trim or No trim

Select second object:

Example 1 : Command: Fillet Current settings: Mode = NOTRIM, Radius = 0 Select first object or [Undo/Polyline/Radius/Trim/Multiple]: R Specify fillet radius <0> : 5 Select first object or [Undo/Polyline/Radius/Trim/Multiple] <0>: pick 1st object Select second object or shift-select to apply corner: pick 2nd object

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Example 2 : Command: Fillet Current settings: Mode = NOTRIM, Radius = 0 Select first object or [Undo/Polyline/Radius/Trim/Multiple]: R Specify fillet radius <0> : 8 Select first object or [Undo/Polyline/Radius/Trim/Multiple] <0>: pick 1st object Select second object or shift-select to apply corner: pick 2nd object

CHAMFER Using Chamfer is a fast way of creating a line between two nonparallel lines. It is usually used to represent a beveled edge on a corner. Chamfer can also be used to bevel all corners of the polyline.

There are two methods of doing this.

1. Type Chamfer or just cha at the command prompt.

2. Click Chamfer from the Modify toolbar.

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CHAMFER

Trim

Angle

Trim or No trim

Angle 1st line

Select 1st line

Distance 1st chamfer distance 1st chamfer distance

Select 2nd line: Example 1 : Command: Chamfer Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: d Specify first chamfer distance <0.0000>: 3 Specify second chamfer distance <1.0000>:2 Select 1stline or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: pick 1st ine Select 2nd line or shift-select to apply corner: pick 2nd line

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Example 2 : Command: Chamfer (NOTRIM mode) Current chamfer Dist1 = 3.0000, Dist2 = 2.0000 Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: t Enter Trim mode option [Trim/No trim] <No trim>: t Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: a Specify chamfer length on the first line <0.0000>: 4 Specify chamfer angle from the first line <0>: 45 Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]: pick 1st line Select second line or shift-select to apply corner: pick 2nd line OFFSET The Offset command draws an entity parallel to another entity at either specified distance or through a specified point. Line, arc, circle and 2D pline are the entities that can be offset.

There are two methods of doing this.

1. Type Offset at the command prompt.

2. Click Offset from the Modify toolbar.

OFFSET Example 1 : Command: Offset Current settings: Erase source=No Layer=Current OFFSETGAPTYPE=0 Specify offset distance or [Through/Erase/Layer] <0>: 5 Select object to offset or [Exit/Undo] <Exit>: pick original object Specify through point : select a point

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CHANGE This command is used to change the points and properties of objects that have been drawn. At command line type Change Example 1: Command: change Select objects: pick original line Specify change point or [Properties]: p Enter property [Color/Elev/LAyer/LType/ltScale/LWeight/Thickness/Material/Annotative]: LT Enter new linetype name <Continuous>: dashed Enter property to change [Color/Elev/LAyer/LType/ltS :

PEDIT It is used for editing and joining Polylines. At command line type Pedit.

Example 1: Command : Pedit Select polyline or [Multiple] : pick original pline Enter [Close/Join/Width/Edit Vertex/Fit/Spline/Decurve/Ltype gen/Undo] : w Specify new width for all segments: 2 ( original pline width=1)

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Example 2: Command: pedit Select polyline or [Multiple]: pick polyline Enter [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: close Enter [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: Spline

polyline

Pedit change to Spline

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OBJECT SNAPS Object Snaps allow objects to be added to a drawing at precise positions in relation to other objects already on screen. With Object Snaps, objects can be added to the endpoints and midpoints, to intersections of objects, to centers and quadrants of circles and so on. Object Snaps also override snap points even when snap is set on.

To set Object Snaps – at the command line: Command: OS enter, and the Drafting Settings dialog appears. Click the Object Snap tab in the upper part of the dialog and click the check boxes to the right of the Object Snap names to set them on (or off in on).

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When Object Snaps are set ON (F3), as outlines are constructed using Object Snaps so Object Snap icons and their tooltips appear.

.

With Object Snaps off, the following abbreviations can be used by the keyboard and type 1st three words of the object snaps command.

Examples: CENter

snaps from or to the center of an arc or circle.

ENDpoint

snaps from or to the closest end of any object

EXTention

snaps from or to a point along the extension of a line or

arc INSertion

snaps from or to the insertion point of a block

INTersection

snaps from or to the intersection of two items Computer Aided Electrical Drawing

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MIDpoint

snaps from or to the midpoint of a selected item

NEARest

snaps from or to a point on an object nearest to the

digitized point NODe

snaps from or to a point created by POINT, DIVIDE, or MEASURE

NONe

turns the Object Snap mode off

PARallel

draws a line parallel to an existing line

PERpendicular

snaps to a 90-degree angle to an existing line

QUAdrant

snaps from or to the 0, 90, 180, or 270-degree point on an arc, circle, or ellipse snaps from or to the tangent of an arc or circle

TANgent

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07

DISPLAY CONTROL

ZOOM You can change the magnification of a view by zooming in and out. Like zooming in and out with a camera, Zoom does not change the absolute size of objects in the drawing; it changes only the magnification of the view. When you work with minute parts in your drawing, you may need to zoom out frequently to see an overview of your work. Use Zoom Previous to return quickly to the prior view. There are two methods of doing this.

1. Type Zoom or just Z at the command prompt.

2. Click Zoom from the Zoom toolbar.

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ALL Zooms to display the entire drawing, AutoCAD zooms to the drawing limits or current extents, which ever is greater. The display shows all objects even if the drawing extends outside the drawing limits.

Example : Command: Zoom Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: all

CENTER Zooms to display a window by entering a center point. Then enter a magnification value or height. A smaller value for the height increases the magnification. A larger value decreases the magnification.

Example : Command: Zoom Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: c Specify center point: pick center point Enter magnification or height <300>: 10

DYNAMIC Zooms to display the generated portion of the drawing with a view box. The view box represents your viewport, which you can shrink or enlarge and move around the drawing. Positioning and sizing the view box pans or zooms to fill the viewport with the image inside the view box. The panning view box is displayed first. Drag it to the location you want and click. The zooming view box is then displayed. Resize it and press ENTER to zoom or click to return to the panning view box.

Command: Zoom Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: d Press ENTER to view Dynamic1, move to dynamic 2 (move right to change window size) view after press ENTER.

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EXTENTS Zooms to display the drawing extents and this will result in the largest possible display of all the objects.

Example : Command: Zoom Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: e

PREVIOUS Zooms to display the previous view. You can restore up to 10 previous views.

SCALE (X/XP) Zooms the display at a specified scale factor.

Enter a scale factor (nX or nXP): Specify a value Example : Command: Zoom Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: s Enter a scale factor (nX or nXP): 2

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The value you enter is relative to the limits of the drawing. For example, entering 2 doubles the apparent display size of any objects from what it would be if you were to zoom to the limits of the drawing.

WINDOW Zooms to display an area specified by two opposite corners of a rectangular window.

Specify first corner: pick point first corner Specify opposite corner: pick point other corner

PAN It provides for the viewing of a different portion of a drawing on the display screen without changing the magnification. If you enter Pan at the command prompt, Pan presents alternative prompts on the command line. This version of Pan works in two ways. You can specify a single point by indicating the relative displacement of the drawing with respect to the current location. You can also specify two points, in which case AutoCAD computes the displacement from the first point to the second point.

There are two methods of doing this.

1.

Type Pan at the command prompt.

2.

Click Pan Realtime from the Standard toolbar.

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REDRAW AutoCAD redraws the current viewport, removing marker blips. It also displays artifacts (stray pixels) left by editing commands. Type Redraw or just R at the command prompt.

Use the Redraw command to: •

Refresh the display.

•

Remove all graphics remnants such as blips, stray pixels, etc.

REGEN The Regen and Redraw commands seem to have similar functions. Although their functions appear to be similar, the Redraw and Regen commands are significantly different. Type REGEN at command prompt: •

Regenerate entire drawing data.

•

Recompute the screen coordinates.

•

Reindex the drawing database for maximum performance (recreates the display list).

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08

BLOCK, WBLOCK AND INSERT BLOCK

Drawing the resistor, transformer, and ceiling fan in previous workbook might have taken what seemed to you an inordinate amount of time. As you continue to use AutoCAD, however, you will learn to draw objects more quickly. You will also need to draw fewer of them because you can save drawings as symbols and use them as rubber stamps, duplicating drawings instantaneously wherever they are needed. This saves a lot of time when you’re composing drawings. To make effective use of AutoCAD, begin a symbol library of drawings you use frequently. A mechanical designer might have a library of symbols for fasteners, cams, valves, or any type of parts for their application. An electrical engineer might have a symbol library of capacitors, resistors, switches, and the like. A circuit designer will have yet another unique set of frequently used symbols.

Create a symbol library

BLOCK To save a drawing as a symbol, you use the Block tool. In word processors, the term block refers to a group of words or sentences selected for moving, saving, or deleting.

You can copy a block of text elsewhere within the same file, to other files, or to a separate file or disk for future use. AutoCAD uses blocks in a similar fashion. Within a file, you can turn parts of your drawing into blocks that can be saved and recalled at any time. You can also use entire existing files as blocks. You’ll start by opening the file you worked on in the last chapter and selecting the objects that will become a block.

1. Start AutoCAD and open the existing Bath file. Use the one you created in, or Assignment 3(electronic & electric).dwg on the floopy disk. Metric users can use the Assignment 3(electronic & electric).dwg file. The drawing appears just as you left it in the last session.

2.

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3. .In the Draw toolbar, click the Make Block tool or type B ↵ , the keyboard shortcut for the Make Block tool, to open the Block Definition dialog box. You can also choose Draw ↵ Block ↵ Make.

BLOCK Block name : type name of block (resistor)

Base point : pick base point (use ENDpoint)

Select object : pick object

Block unit : select unit(millimeter)

4. Block command cannot be saved to your alternative drive.

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WBLOCK ( write block ) Using the WBLOCK command, you also can make your library automatically save to your destination.

Command: WBLOCK ↵

WBLOCK Base point : pick base point (use ENDpoint)

Select object : pick object (resistor)

Block unit : select millimeter

Destination : select path for destination file

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INSERT BLOCK There are two methods of doing this.

5.

Type INSERT at the command prompt. OR

6.

Click Insert Block from the Draw toolbar.

INSERT Browse file : resistor

Insertion point : pick point or coordinates

Scale : 1:1

MINSERT

Rotation : 0

The MINSERT command (AutoCAD only) lets you insert blocks in a rectangular array.

There is one method of doing this.

1. Type MINSERT at the command prompt.

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Command: MINSERT MINSERT Enter block name or [?]: D:\electronic component\resistor Units: Millimeters Conversion:

1.0000

Specify insertion point or [Basepoint/Scale/X/Y/Z/Rotate]: pick point or coodinate Enter X scale factor, specify opposite corner, or [Corner/XYZ] <1>: 1 Enter Y scale factor <use X scale factor>: 1 Specify rotation angle <0>: 0 Enter number of rows (---) <1>: 1 Enter number of columns (|||) <1>: 1

MINSERT prompts you for an insertion point, scale factors, and rotation angle using the same prompts as the INSERT command, but without the dialog box. It then starts the same prompts as the Rectangular option of the ARRAY command, asking for the number of rows and columns and the distance between them. The value of MINSERT is that it reduces the size of your drawing because the array is one block object. The disadvantage is that you can’t edit the individual blocks in the array or the array as a whole in any way. If you need to edit them, erase the entire array of blocks, redefine the single block, if necessary, and start over, this time using INSERT and ARRAY separately. You cannot explode a minsert block.

EXPLODE You can explode blocks into their original objects. You may need to do this to edit a block. If you want, you can then redefine the block. The insert block object cannot be modified if that insert block object does not explode first.

There are two methods of doing this.

1. Type EXPLODE at the command prompt.

2. Click EXPLODE from the Modify toolbar.

Example : Command: explode ↵ Select objects: pick object ( insert block object ) ↵ Select objects: ↵ Computer Aided Electrical Drawing

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You can also explode polylines, dimensions, hatches, regions, multilines, and certain 3D objects (bodies, 3D meshes, 3D solids, various types of surfaces, polyface meshes, and polygon meshes) into simpler types of objects. Exploding a block with nested blocks explodes only the top-level block. You need to use EXPLODE again to explode the next level of blocks. When you explode blocks that were created on layer 0 or with BYBLOCK objects, the objects return to their original status and appear black/white with a continuous linetype and default lineweight again.

If you insert a block with different X and Y scales, the command does its best to create objects based on their new shapes. For example, if you have a block that includes a circle and insert it with an X scale of 1 and a Y scale of 2, you see an ellipse. Therefore, when you explode the block, you get an ellipse from what used to be a circle.

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09

LAYER, LINETYPE AND COLOR

LAYER COMMANDS The command line version of Layer creates new layers; sets the current layer; sets the color, linetype, lineweight, and plot style for designated layers; turns layers on and off; turns plotting on and off for visible layers; locks and unlocks layers; freezes and thaws layers; and lists defined layers.

There are three methods of doing this.

1. Type Layer or just La at the command prompt.

2. Click the layers icon from the Object Properties toolbar.

You will see the Layer Properties Manager Dialog Box as shown below.

New It creates a new layer. After you choose New, the list displays a layer named LAYER1.

You can edit this layer immediately. To create multiple layers more quickly, you can select a layer name for editing and enter multiple layer names separated by commas.

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If you create a new layer, the new layer inherits the properties of the currently selected layer in the layer list (Color, On/Off state, and so on). To create layers with default settings, make sure that there are no selected layers in the list or that you select a layer with default settings before beginning layer creation.

Current Sets the selected layer as the current layer. The CLAYER system variable stores the layer name.

Delete Deletes selected layers from the drawing file definition. You can delete only unreferenced layers. Referenced layers include layers 0 and DEFPOINTS, layers containing objects (including objects in block definitions), the current layer, and xrefdependent layers. Layers that do not contain objects (including objects in block definitions), are not current, and are not xref-dependent can be deleted by using the PURGE command.

Show/Hide Details Controls whether the Details section is displayed in the Layer Properties Manager.

Save State Displays the Save Layer States dialog box, in which you save layer state and layer properties settings of all layers in a drawing. You can choose which layer states and properties that you want to preserve. You save a layer state by assigning it a name.

Any layer states saved in a drawing that is inserted in your current drawing as a block are also added to the current drawing.

Restore State Displays the Layer States Manager, in which you can manage named layer states.

List of Layers Displays layers and their properties. To modify a property, click its icon. To quickly select all layers, right-click and use the shortcut menu.

•

Names Displays the names of the layers. You can select a name and then click and enter a new name.

•

On/Off Computer Aided Electrical Drawing

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Turns layers on and off. When a layer is on, it is visible and available for plotting.

When a layer is off, it is invisible and not plotted, even if the Plot is on.

•

Freeze/Thaw in All Viewports Freezes selected layers in all viewports. You can freeze layers to speed up ZOOM, PAN, and many other operations; improve object selection performance, and reduce regeneration time for complex drawings. AutoCAD does not display, plot, hide, render, or regenerate objects on frozen layers. Freezes the layers you want to be invisible for long periods. When you thaw a frozen layer, AutoCAD regenerates and displays the objects on that layer. If you plan to switch between visible and invisible states frequently, use the On/Off setting. You can freeze layers in all viewports, in the current layout viewport, or in new layout viewports as they are created.

•

Lock/Unlock Locks and unlocks the layers. You cannot edit objects on a locked layer. Locking a layer is useful if you want to view information on a layer for reference but do not want to edit objects on that layer.

•

Color Changes the color associated with the selected layers. Clicking the color name displays the Select Color dialog box.

•

Linetype Changes the linetype associated with the selected layers. Clicking any linetype name displays the Select Linetype dialog box.

•

Lineweight Changes the lineweight associated with the selected layers. Clicking any lineweight name displays the Lineweight dialog box.

•

Plot Style Displays a list of plot styles available to apply to the selected layers. If you are working with color-dependent plot styles (the PSTYLEPOLICY system variable is set to 1), you cannot change the plot style associated with a layer. The default plot style is Normal.

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HOW TO SET LINETYPES AND COLOR You can use color to help you group objects visually. You can assign the color of an object either by layer or by specifying its color explicitly, independent of a layer.

Assigning colors by layer makes it easy to identify each layer within your drawing.

Assigning colors explicitly provides additional distinctions between objects on the same layer.

Linetype To load a linetype 1. From the Format menu, choose Linetype.

2. In the Linetype Manager, choose Load.

3. In the Load or Reload Linetypes dialog box, select a linetype and choose OK.

If the linetype you need is not listed, choose File. In the Select Linetype File dialog box, select a LIN file whose linetypes you want to list and choose Open. The dialog Computer Aided Electrical Drawing

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box displays the linetype definitions stored in the selected LIN file. Select a linetype and choose OK. To list the linetypes loaded in the current drawing 1. On the Object Properties toolbar, click the Linetype control.

All loaded linetypes are displayed in the list. If necessary, use the scroll bar to see the whole list.

2. Click anywhere outside the box to close it.

Colors To set the color for all new objects 1. On the drop-down icon below;

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Color control displays the current color.

To change the color of an object, overriding the layer's color 1. On the Standard toolbar, click Properties.

2. Select the objects whose color you want to change.

3. In the Properties window, select Color.

To change the color assigned to a layer 1. On the Object Properties toolbar, click Layers.

2. In the Layer Properties Manager, click the color you want to change.

3. In the Select Color dialog box, click a color or enter a color number (1-255) or name.

4. Choose OK to exit each dialog box. An arrow is displayed in the right column.

4. Click the arrow and select a color from the list.

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10

DIMENSIONING

IMPORTANCE AND BENEFITS OF DIMENSIONING DRAWINGS Dimensioning is the process of adding measurements to a drawing. Dimensions show the geometric measurements of objects, distances or angles between objects or the X and Y coordinates of a feature. Every dimension style controls colour, text style and linetype scale.

Dimensioning is the process of adding measurement annotation to a drawing.

AutoCAD provides many ways to dimension objects and many ways to format dimensions. You can create dimensions for a wide variety of object shapes in many different orientations. You can create dimension styles to format dimensions quickly and ensure that dimensions in your drawing conform to industry or project standards.

Dimensions show the measurements of objects, the distances or angles between objects, or the distance of a feature from an origin you specify. AutoCAD provides three basic types of dimensioning: linear, radial, and angular. Dimensions can be horizontal, vertical, aligned, rotated, ordinate, baseline, or continued.

You can dimension objects, such as lines, arcs, circles, and polyline segments, or you can dimension between point locations.

AutoCAD places dimensions on the current layer. Every dimension assumes the current dimension style, which controls characteristics such as arrowhead style, text location, and lateral tolerances. With dimension styles, you can make subtle modifications to a base dimension style for different types of dimensions. With dimension style overrides, you can modify these characteristics for a specific dimension.

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Origin point is an origin point defines the measurement value for the dimension text and is a small nonprinting point attached to the dimension. Origin points are typically placed on an object and allow you to move or reposition a dimension that may need to be updated.

Extension line is an extension line extends up to the dimension line and arrowheads and indicates which feature or points on an object are being dimensioned. An extension line typically has a gap between it and the origin point of the dimension object and extends past the dimension line. The gap helps show that the dimension is not part of the object.

Arrowhead is an arrowhead appears at the end of a dimension line and indicates where a dimension starts and ends. Arrowheads can be displayed as open or closed arrows, architectural ticks, dots, or user defined arrows, among other arrowhead styles.

Dimension line is a dimension line is typically displayed between the extension lines and goes outward from the center of the dimension object toward the extension line.

Based on where the dimension text is placed, the dimension line may appear broken or on the outside of the extension lines.

Dimension text is a dimension text provides the value of measurement with which the dimension was created and can be formatted in a variety of ways. Some of the formatting options are the units of measurement, the type of decimal separator that is used, and how the value should be rounded.

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Click Annotate to make dimension

LINEAR There are two methods of doing this.

1. Type DIMLINEAR 0r 2. Click Linear icon

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Example : Command: _dimlinear Specify first extension line origin or <select object>: pick 1st line origin Specify second extension line origin: pick 2nd line origin Specify dimension line location or [Mtext/Text/Angle/Horizontal/Vertical/Rotated]: Specify dimension line location or [Mtext/Text/Angle/Horizontal/Vertical/Rotated]: Dimension text = 10

RADIUS

Example :

Command: _dimradius Select arc or circle: Dimension text = 6 Specify dimension line location or [Mtext/Text/Angle]: M Specify dimension line location or [Mtext/Text/Angle]:

DIAMETER

Command: _dimdiameter Select arc or circle: Dimension text = 20 Specify dimension line location or [Mtext/Text/Angle]: M Specify dimension line location or [Mtext/Text/Angle]:

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ALIGNED

Example :

Command: _dimaligned Specify first extension line origin or <select object>: Specify second extension line origin: Specify dimension line location or [Mtext/Text/Angle]: M Specify dimension line location or [Mtext/Text/Angle]: Dimension text = 8

ANGULAR

Example : Command: _dimangular Select arc, circle, line, or <specify vertex>: pick 1st line Select second line: pick 2nd line Specify dimension arc line location or [Mtext/Text/Angle/Quadrant]: Dimension text = 28

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DIM STYLE AND VARIABLE You can control the appearance of dimensions by changing settings. For convenience and to help maintain dimensioning standards, you can store these settings in dimension styles.

There are two methods of doing this.

1. Type Dimstyle at command prompt or 2. Click Format >> Dimension Style from the pull-down menu bar.

Set Current Sets the style selected under Styles to current.

New Displays the Create New Dimension Style dialog box, in which you can define new dimension styles. See New, Modify, and Override Dimension Style Dialog Boxes.

Click New to open the Create New Dimension Style dialog box above. With the copy name highlighted in the New Style Name input box, enter a new name for your style.

Check to make sure your dimension style name conforms to any standards that other members of the team might be using.

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Modify Displays the Modify Dimension Styles dialog box, in which you can modify dimension styles. Dialog box options are identical to those in the New Dimension Style dialog box. See New, Modify, and Override Dimension Style Dialog Boxes.

Override Displays the Override Current Style dialog box, in which you can set temporary overrides to dimension styles. Dialog box options are identical to those in the New Dimension Style dialog box. See New, Modify, and Override Dimension Style Dialog Boxes. AutoCAD displays override as unsaved changes under the dimension in the Styles list.

Compare Displays the Compare Dimension Styles dialog box, which compares the properties of two dimension styles or lists all the properties of one style.

Click Modify from Dimension Style Manager. You can see as shown below.

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New Dimension Style dialog box.

From this dialog box, we can change: i.

Lines and Arrows

ii.

Text

iii.

Fit

iv.

Primary Units

v.

Alternate Units

vi.

Tolerances

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11

PLOTTING

PREPARATORY STEPS FOR PLOTTING Once you have completed a drawing, you can use a number of methods to output the drawing. You can plot the drawing on paper or create a file for use with another application. In either case, you select the plot settings.

There are two methods of plotting.

1. Type Plot at the command prompt.

2. Click Plot from the Output Toolbar.

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3. The dialog box appears shown above.

To plot a drawing From the File menu, choose Plot.

1. In the Plot dialog box. i.

Select a printer or plotter name that wants to use.

ii.

Select paper size of printer/plotter for example – A2, A3 or A4.

iii.

Drop down plot area – select display, extents, limits or window.

iv.

At plot scale –choose fit to paper or custom scale.

v.

Plot offset – origin set to a printable area ( x and y coordinate ) or center the plot.

vi.

Put the number of copies.

vii.

Press OK.

PLOT AREA When plotting a drawing, you must specify the area of the drawing to plot. The Plot Settings tab in the Plot dialog box provides six options under Plot Area.

Layout or Limits When plotting a layout, this option plots everything within the margins of the specified paper size, with the origin calculated from 0,0 in the layout. When plotting on the Model tab, it plots the entire drawing area defined by the drawing limits. If the current viewport does not display a plan view, this option has the same effect as the Extents option.

Extents Plots the portion of the current space of the drawing that contains objects. All geometry in the current space is plotted. AutoCAD may regenerate the drawing to recalculate the extents before plotting.

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Display Plots the view in the current viewport in the Model tab or the current paper space view in a layout tab.

View Plots a view saved previously with the VIEW command. You can select a named view from the list provided. If there are no saved views in the drawing, this option is unavailable.

Window Plots any portion of the drawing you specify. Click the Window button to use a pointing device to specify opposite corners of the area to be plotted or enter coordinate values.

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REFERENCES

1.

Autodesk (2014) AutoCAD 2014 : User’s guide

2.

Khairul Anuar Hanfiah (1996) Lukisan Kejuruteraan Berbantu Komputer Skudai : Universiti Teknologi Malaysia

3.

http://en.wikipedia.org/wiki/Electronic_symbol

4.

https://www.rapidtables.com/electric/electrical_symbols.htm

5.

http://www.rapidtables.com/electric/Electronic_components.htm

6.

http://lukisankejuruteraankvkk.blogspot.com/2014/03/lukisan-simbolelektrik-dan-elektronik.html

Computer Aided Electrical Drawing