Dr. Kevin WongIndustrial Centre

Introduction to AutoCAD Engineering Drawings

Learning Outcomes

• Upon completion of the workshop, students should be able to:

a) Explain the principle and conventional representation of engineering drawings according to engineering standards,

b) Apply the features and functions of typical CAD systems for producing CAD drawings,

c) Communicate through CAD drawings.

Manual Drawing Vs CAD

Introduction to CAD Computer Aided Drafting/Design

• Basic skills for nowadays’ Engineer• Communication media among different discipline of people in different

place• Can be simply classify into 2 types of CAD system – 2D and 3D• Some advantages of using CAD

– Accuracy • An accuracy of up to 14 decimal places

– Speed• Revising and editing drawings can be done quickly with minimum

effort• Reuse of drawing content can be done easily

– 3D Representation and Analysis• Interference checking and 3D animations can be easily performed

Introduction to CAD

Get a Trial Version (30-days)http://usa.autodesk.com/autocad/trial/

• AutoCAD• One of the most well-known 2D CAD software

developed by Autodesk• Widely be used to output construction drawings for

civil engineering, architecture, and building services• Other applications include electrical PCB design,

garment design and facility management

AutoCAD2015 Free Trial

Engineering Drawing Created by AutoCAD

Architecture Drawing Created by AutoCAD

Starting AutoCAD

Start up > Autodesk > AutoCAD Mechanical 2015 > AutoCAD 2015

Auto CAD 2015

User Interface (AutoCAD classic)

Current File NameMenu Bar

Toolbar

(Icon)

Layers

X, y, z coordinate system

Draw Toolbar

Status Bar

User Coordinate System (UCS)

Graphic

cursor

Drawing Area(Graphic Window)

AutoCAD User Interface

TabsClick here to expand panel

Tooltip

AutoCAD User InterfaceDynamic Input• The key allows you to toggle between the different input field• The key allows you to display a list of valid command options

Length Dimension

Cursor

Current Input Field

Dynamic Prompt

Angle Dimension

Mouse Interface

Left button Click the specific points and select pull down menu or graphic icon(Selection)

Right buttonClick to activate the right click menu

Middle button Scroll to zoom in or zoom out

Keyboard InterfaceEnterGo to next step of command / repeat last command

SpacebarGo to next step of command / repeat last command

DeleteTo erase lines or any sketches

To Set Up a Drawing• Step 1: New a draw

Show the Menu barFile > New > OK

3

Menu Bar

1

2

To Set Up a Drawing• Step 2: Define the drawing units

Format > Unit > Millimeters > OK

1

2

3

4

• Step 3: Load the line typesFormat > Line Type > LoadCommon used linetype:- Continuous , Hidden, Center, Dashed

To Set Up a Drawing1

2

3

4

• Step 4: Create layer for drawing controlFormat > Layer > New LayerNew – Create a new layerDelete – Delete a layerCurrent – Set the selected layer to be the active layerColor – Set layer’s colorLinetype – Select/Load linetype for a layerLineweight – Select the thickness of the line for a layer.

To Set Up a Drawing1

2

3

AutoCAD User Interface• Draft Setting

- Turn on and off the options by clicking on the buttons in the status bar

Snap ModeGrid Display Ortho Mode

Polar TrackingObject Snap

Object Snap Tracking Allow/Disallow Dynamic UCS

Dynamic Input

Show/Hide Lineweight

Quick Properties

Off StatusOn Status

Remark:Status Bar

Infer Constraints

Dwing Sheet

• Step 5: Define the drawing limitsFormat > Drawing Limits

To Set Up a Drawing1

2Specific lower left corner: E.g.: 0,0 Specific upper right corner: E.g.: 420, 297

420

297 Drawing Sheet

• Line – By specify

• Co-ordinates (start & end point)

• Dynamic input (start point, distance & angle)

Command of line = l

• Rectangle- By specify

• Co-ordinates (first corner point & other corner point)

Command of rectangle = rec

Draw Command - Line & Rectangle• Line & Rectangle

0,0

@10,3

0,0

10

300,0

@10,3

• Draw with Absolute Cartesian Coordinate 0,0 *4,0 *2,3 *0,0

+X

+Y

-XX=0, Y=0

1 2 3 4 5

-5 -4 -3 -2 -1 1

2

3

-2

-1

2,3

0,0 4,0

Absolute

• Draw with Absolute Polar Coordinate 0,0 * 4<180 *4<120 *0<120

X-coordinate Y-coordinate

180o

0,0

0,0

Absolute Distance Angle

120o

*4<180

*4<120

*0<120

Features of AutoCAD

+X, +Y

+X, -Y-X, -Y

-X, +Y

• Draw with Relative Cartesian Coordinate -2,1 @5,0 @0,2 @-5,-2

+X

+Y

-XX=0, Y=0

1 2 3 4 5

-5 -4 -3 -2 -1 1

2

3

-2

-1

+X, +Y

+X, -Y-X, -Y

-X, +Y

Features of AutoCAD

@0,2

@5,0

Relative

• Draw with Relative Polar Coordinate 0,0 @ 5<0 @3<90 @5.83<211

X-coordinate Y-coordinate

-2,1

Relative Distance Angle

90o

@3<90

211o

@5<0@5.83<211

@-5,2

Activity 1Write a list of relative coordinates used to draw the following figure

Cartesian0,0......

Polar0,0......

50

Activity 1 - Solution

50

Cartesian0,0@50,0@0,10@-10,0@-30,40@0,10@-10,0@0,-60

Polar0,0@50<0@10<90@-10,0 (@10<180)@50<127@10<90@-10<0(@10<180)@60<270

Write a list of relative coordinates used to draw the following figure

• View > Zoom > All• View > Zoom > Window• View > Zoom > In• View > Zoom > Out

Zoom

Zoom > All

Zoom > Window

Zoom > In

Zoom > Out

• Circle – By specify

• Center point & radiusCommand of circle = c

• Ellipse- By specify

• Center point, first end point of axis with angle & distance of other axis

Command of ellipse = el

Draw Command – Circle & Ellipse• Circle & Ellipse

0,0

10@15<0o

0,0

10

• Center, Star, End Arc – By specify

• Co-ordinates (center point, start point of the arc & end point of the arc)• Dynamic input (center point, radius with angle & end point of the arc)

Command of arc = a

Draw Command – Arc• Center, Star, End Arc

0,0@10<0o

500,0

@10<0o

135

Modify Command – Copy & Move• Copy & Move

• CopyStep 1. Select object to copyStep 2. Select base pointStep 3. Specify the point to move

Command of copy = co/cp

• MoveStep 1. Select object to moveStep 2. Select base pointStep 3. Specify the point to move

Command of lengthen = mo

Modify Command – Trim & Extend• Trim & Extend

• TrimStep 1. Select object to act as the

boundaryStep 2. Select object to trim

Command of trim = tr

• ExtendStep 1. Select object to act as the

boundaryStep 2. Select object to extend

(please noted that the location of the selected point define which side to extend)

Command of extend = ex

Modify Command – Fillet & Chamfer• Fillet

• FilletStep 1. Type in “r” for radiusStep 2. Input the radius (e.g. 10)Step 3. Select the first edge & second edges to form the radius

Command of fillet = f

R10

• Chamfer Length & AngleStep 1. Type in “d” for distanceStep 2. Input the first chamfer

distanceStep 3. Input the chamfer angle

from the first line. Step 4. Select the first & second

lines to form the chamferCommand of chamfer = cha

Modify Command –Chamfer• Chamfer

• Chamfer Two DistancesStep 1. Type in “d” for distanceStep 2. Input the first & second

chamfer distanceStep 3. Select the first & second

lines to form the chamferCommand of chamfer = cha

First d

Second d

First d

Angle

Practical Exercise 1• Use the (50,50) be starting point

Staring Point

Practical Exercise 2• Starting point B is (370,90) and use discretion for sizes not given

Staring Point