EC202 - PW2

1. EC202-Computer Aided Design
PRACTICAL EVALUATION FORM
NAME:………………………………………………………. CLASS.: ………………
REGISTRATION NO.: ………………………………………
PRACTICAL WORK: 2
INTRODUCTION TO AUTOCAD WINDOWS: DATA INPUT TECHNIQUES
No.
Skill
i. Accuracy
ii. Within time frame
Excellent
(8-10 marks)
amy/khk/jke/puo EC2.1
Average
(5-7 Marks)
Weak
(0-4 Marks)
Total
1.
Create New file- Metric
measurement & able to
display grid
2. Absolute Coordinate Method
3. Relative Coordinate Method
4. Polar Coordinate Method
Sub-Total /40
No. Report Total
1. Result: Table 2.1 /10
2. Discussion /4
3. Question /4
2. Reflection /2
Sub-Total /20
Total /60

2. EC202-Computer Aided Design
PRACTICAL WORK: 2
TITLE : INTRODUCTION TO AUTOCAD FOR WINDOWS
COURSE LEARNING OUTCOME:
CLO3: Key-in data and commands using various data input techniques to produce
standard drawing.
OBJECTIVES: The students should be able to:
1. Key-in data entries by using:
a. Absolute Coordinate system technique.
b. Relative Coordinate system technique.
c. Polar Coordinate system technique
2. Compare the techniques of data inputs.
THEORY :
Designs and drawings created in a CAD system are usually defined and stored using sets of
points in what is called world space. In most CAD systems, the world space is defined using
a three-dimensional Cartesian coordinate system, usually referred to as the X, Y, and Z-axes.
The intersection of the three coordinate axes forms a point called the origin, a fixed point
being used as a reference for all measurements.
The icon near the bottom left corner of the graphics window shows the positive X-direction
and positive Y-direction of the coordinate system that is active. In AutoCAD, the coordinate
system that is used to create entities is called the User Coordinate System (UCS). By default,
the UCS is aligned to the world coordinate system (WCS). In AutoCAD, there are various
methods to specify the locations of points:
i. Random point or interactive technique
ii. Absolute coordinates system
iii. Relative coordinates system
iv. Polar coordinates system
v. Direct distance entry technique
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3. EC202-Computer Aided Design
EQUIPMENT : 1. Desktop Computer/Laptop
2. AutoCAD 2004 Software
PROCEDURE :
PART A: Start The AutoCAD Program
1. Create a New drawing file and set the drawing measurement to Metric.
2. Display the grid to the extent of the drawing limits.
PART B: DATA INPUTS
1. We will make use of the DRAW command <line> to start our drawing and then
followed by the Data Entries techniques.
 Select the Line command from either one of the following methods:
i. The Pull-Down Menu <DRAW>
Fig. 2.1: Pull-down menu selection <DRAW> Line
ii. The Toolbar Draw
Fig. 2.2: Draw Toolbar icon <Line>
iii. Typing Line or L at the Keyboard
Fig. 2.3: Keyboard Entry
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4. EC202-Computer Aided Design
 Observe the message displayed at the Command prompt and AutoCAD expects
us to identify the starting location (first point) of a straight line.
2. To begin a drawing, we will start with a simple example such as a rectangle ABCD
as at Fig. 2.4.
In this example , we will choose the origin of the world coordinate system
(WCS) i.e. X,Y = 0,0 as our starting first point.
D
A
Fig. 2.4: A Rectangle ABCD at the UCS origin 0,0
i. Technique 1: Absolute Coordinate System
To locate the next point, type the X-value, Y value (DO NOT add spaces).
Follow the instruction below to draw Fig 2.4:
Command: Line [Enter]
Step 1: To locate the starting point A:
Specify first point: 0,0 [Enter] - To locate the starting point A
Step 2: To locate point B:
Specify next point or [Close/Undo]: 100,0 [Enter]
Step 3: To locate point C:
Specify next point or [Close/Undo]: 100,50 [Enter]
Step 4: To locate point D:
Specify next point or [Close/Undo]: 0,50 [Enter]
Step 5: To locate point A again or to close the object (rectangle):
amy/khk/jke/puo EC2.4
50
100
Y
-X
(0,0)
X
-Y
C
B

5. EC202-Computer Aided Design
Specify next point or [Close/Undo]: C [Enter] OR
Specify next point or [Close/Undo]: 0,0 [Enter]
If a mistake is made, use the undo icon, or press U or press CTRL+Z.
You can also use the ERASE command to get rid of lines you don't want.
ii. Technique 2: Relative Coordinate System
This technique allows you to enter points in relation to the first point you
have entered. To locate the next point, type @deflection of X axis ,
deflection of Y axis (DO NOT add spaces).
Follow the instructions below to draw Fig. 2.4:
Command: Line [Enter]
Step 1: Specify first point: 0,0 [Enter]
Step 2: Specify next point or [Close/Undo]: @100, 0 [Enter]
Step 3: Specify next point or [Close/Undo]: @0,50 [Enter]
Step 4: Specify next point or [Close/Undo]: @-100,0 [Enter]
Step 5: Specify next point or [Close/Undo]: C [Enter] OR
Specify next point or [Close/Undo]: @0,-50 [Enter]
The alphabet @ means that AutoCAD will draw a line from the first point to
another point X unit over Y units up relative to the previous point.
iii. Technique 3: Polar Coordinate System
Polar Coordinates allow you to select a point that is a specific length an at a
specific angle to the last point indicated.
To locate a point, type @distance<angle (DO NOT add spaces).
Follow the instructions below to draw Fig. 2.4:
Step 1: Command: Line [Enter]
Specify first point: 0,0 [Enter]
Step 2: Specify next point or [Close/Undo]: @100<0 [Enter]
Step 3: Specify next point or [Close/Undo]: @50<90 [Enter]
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6. EC202-Computer Aided Design
Step 4: Specify next point or [Close/Undo]: @100<180 [Enter]
Step 5: Specify next point or [Close/Undo]: C [Enter] OR
Specify next point or [Close/Undo]: 50<270 [Enter]
The distance is the length of the line to be drawn, followed by the symbol (<)
and next followed by the desired angle of the line.
PART B: EXERCISE
1. Create a new drawing space using the Metric measurement.
2. Display the grid to the extent of the drawing limits.
3. From the diagram in Fig. 2.5 given below, redraw to full scale:
i. Using Absolute Coordinate System
 The start point is at coordinates X,Y = 20,30
ii. Using Relative Coordinate System
 The start point is at coordinates X,Y = 160,30
iii. Using Polar Coordinate System
 The start point is at coordinates X,Y = 90,120
4. Fill in the data entries of each technique into Table 2.1 as at page EC2.7.
5. Save the drawing file and exit AutoCAD.
6.
Fig. 2.5
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7. EC202-Computer Aided Design
amy/khk/jke/puo EC2.7
(10 Marks
)
RESULT :
Data Entries
Absolute Coordinate System
Relative Coordinate System Polar Coordinate System
Command Line [Enter] Line [Enter] Line [Enter]
Specify Start Point:
(Pt 1)
20,30 160,30 90,120
Specify Next Point:
(Pt 2)
Specify Next Point:
(Pt 3)
Specify Next Point:
(Pt 4)
Specify Next Point:
(Pt 5)
Specify Next Point:
(Pt 6)
Specify Next Point:
(Pt 7)
Specify Next Point:
(Pt 8)
Specify Next Point:
(Pt 9)
Specify Next Point:
(Pt 10)
Specify Next Point:
(Pt 11)
Specify Next Point:
(Pt 12)
Specify Next Point:
(Pt 13)
Specify Next Point:
(Pt 14)
Specify Next Point:
(Pt 15)
Specify Next Point:
(Pt 16)
Specify Next Point:
(Pt 17)
Table 2.1

8. EC202-Computer Aided Design
amy/khk/jke/puo EC2.8
(2 Marks )
(2 Marks )
(4 Marks )
(2 Marks )
DISCUSSION:
1. In the last step of the procedure to complete drawing each figure, you might have
type the alphabet ‘C’ or you might have key-in the data for the end value. Explain
the difference between them.
a. Specify next point or [Close/Undo]: (Keying the alphabet C for close command)
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b. Specify next point or [Close/Undo]: (Keying the data for end value)
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QUESTION :
1. When selecting the Line command, which of the AutoCAD input commands do you
used frequently? Give a reason for your answer.
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REFLECTION:
At the end of this practical work, I have learnt that:
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