Practical work 5

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EC202-Computer Aided Design PRACTICAL EVALUATION FORM NAME:………………………………………………………. CLASS.: ……………… REGISTRATION NO.: ……………………………………… PRACTICAL WORK: 5 APPLICATION OF AUTOCAD PACKAGE IN TECHNICAL AND ELECTRICAL DRAWINGS: CONCEPTS OF DIMENSIONING, LINETYPES AND TEXTSTYLES No . Skill i. Accuracy ii. Within time frame Excellent (8-10 marks) Average (5-7 Marks) Weak (0-4 Marks) Total 1. Setting drawing limits & display grid to extent 2. Fig. 5.15 (Border) 3. Fig. 5.15 (Text) 4. Fig. 5.16 5. Fig. 5.17 6. Dimensioning Objects Sub-Total /60 amy/khk/jke/puo EC5.1

Transcript of Practical work 5

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PRACTICAL EVALUATION FORM

NAME:………………………………………………………. CLASS.: ………………

REGISTRATION NO.: ………………………………………

PRACTICAL WORK: 5

APPLICATION OF AUTOCAD PACKAGE IN TECHNICAL AND ELECTRICAL DRAWINGS: CONCEPTS OF DIMENSIONING, LINETYPES AND TEXTSTYLES

No.

Skill

i. Accuracy

ii. Within time frame

Excellent

(8-10 marks)

Average

(5-7 Marks)

Weak

(0-4 Marks)Total

1.Setting drawing limits &

display grid to extent

2. Fig. 5.15 (Border)

3. Fig. 5.15 (Text)

4. Fig. 5.16

5. Fig. 5.17

6. Dimensioning Objects

Sub-Total /60

No. Report Total

1. Discussions /5

2 Questions /3

3. Reflection /2

Sub-Total /10

Total /70

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PRACTICAL WORK: 5

TITLE : APPLICATION OF AUTOCAD PACKAGE IN TECHNICAL AND

ELECTRICAL DRAWINGS

COURSE LEARNING OUTCOME:

CLO4: Apply the draw and edit commands skillfully to produce simple and

complex technical drawings.

OBJECTIVES: The students should be able to:

1. Make text by using the Text and DText command.

2. Change the properties of Text Styles.

3. Dimension objects by using the dimension command.

4. Make use of the Dimension style to set a suitable scale for geometry,

format and annotation.

5. Set different linetypes according to the drawing requirements.

THEORY :

The correct use of AutoCADs dimension tools is the key to producing clear and concise

measured drawings. Dimensioning in AutoCAD is automatic; lines, arrows and text are all

taken care of by the dimension commands.

When working with dimensions it is very important that line origins are picked accurately so

that the resulting measurement and text are correct. Always use an Osnap to pick dimension

line origins.

The illustration above shows two different dimension styles. The one on the left is the

default style known as STANDARD. The dimension line has arrow heads and the dimension

text is positioned above the line and is drawn using the current text style. The dimension on

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the right has been drawn using a new style. The arrows have been changed to obliques, the

vertical alignment of the text has been centred and the current text style has been changed.

EQUIPMENT : 1. Desktop Computer/Laptop

2. AutoCAD 2004 Software

PROCEDURE :

Part A: The Dimension Command

When you create dimensions, AutoCAD automatically creates a new layer called

"Defpoints". This is a special layer which cannot be deleted or renamed. AutoCAD uses this

layer to store dimension information.

The Dimension command can be started through any one of these three ways:

i. Click at the Pull-Down Menu <DIMENSION> and select the options

Fig. 5.1: Pull-Down Menu <DIMENSION>

ii. Toolbar Dimension

Fig. 5.1: Toolbar Dimension

iii. Accessed through the keyboard

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Fig. 5.3: Message displayed at the Command Promp Area

Dimensioning Principles

There are two basic principles to follow when you add dimensions to a drawing.

1. Assignment of more than one dimension to a feature should be avoided.

2. The reader of the drawing should not be required to do calculation in order to obtain

the dimension of the object.

Components of a Dimension

A dimension consists of four components:

1. A dimension value.

2. A dimension line that is parallel to the direction of the described object.

3. A pair of arrowheads.

4. A pair of extension lines projecting from the object to which the dimension refers.

i. There should be a small gap between the end of the extension line and the

object.

ii. The extension line should project a short distance away from the intersection

with the dimension line.

Fig. 5.4: Components of Dimension

The Linear Dimension Commands

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The Linear dimension commands are used to dimension along straight lines. There are five

linear dimension commands, namely: DIMLINEAR, DIMCONTINUE, DIMBASELINE,

DIMALIGNED and DIMROTATED. The DIMLINEAR command is probably the most

common dimension command you will use.

The Linear Dimension Command

After starting the command, specify the two points between which you want the dimension

to be drawn and pick a point to fix the position of the dimension line. You can use this

command to generate horizontal and vertical dimensions.

Toolbar

Pull-down Dimension Linear

Keyboard DIMLINEAR

Command Sequence

Command: DIMLINEAR

First extension line origin or press ENTER to select: (pick P1)

Second extension line origin: (pick P2)

Dimension line location (Mtext/Text/Angle/Horizontal/Vertical/Rotated): (pick a

point to position the dimension line, you will see the dimension rubber banding)

You may have noticed that the first prompt asks you to pick the first extension line origin or

to press the ENTER key. Pressing the Enter/Return key results in the following prompt:

Select object to dimension:

AutoCAD allows you to dimension an object simply by picking it.

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Dimensions will automatically adjust themselves to accommodate most situations. For

example, the illustration on the right shows what happens to a dimension if the gap between

the two extension lines is too small for the dimension text.

The Continue Dimension Command

The Continue command adds a string of dimensions.

Toolbar

Pull-down Dimension Continue

Keyboard DIMCONTINUE

Command Sequence:

Command: DIMCONTINUE

Specify a second extension line origin or (Undo/<Select>): (pick P3)

Specify a second extension line origin or (Undo/<Select>): (pick another or to

End

The first dimension (P1P2) was drawn with the DIMLINEAR command; all the other

dimensions were drawn using the DIMCONTINUE command by simply picking the four

points, P3, P4, P5, P6 one after the other.

The Baseline Dimension Command

This command generates a series of dimensions from a single base point. The first

dimension is created with the DIMLINEAR. The DIMBASELINE command then creates

further dimensions in a similar way to the DIMCONTINUE command.

Toolbar

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Pull-down Dimension Baseline

Keyboard DIMBASELINE

Command Sequence:

Command: DIMBASELINE

Specify a second extension line origin or (Undo/<Select>): (pick next point)

Specify a second extension line origin or (Undo/<Select>): (pick another or to

end)Select base dimension: ( again to end)

The first dimension P1P2 was created using the DIMLINEAR command. The others were

created using DIMBASELINE by picking points P3 and P4.

The Aligned Dimension Command

These are dimensions along inclined lines which cannot be dimensioned with the

DIMLINEAR dimension command because that command will only give a measured

dimension in either a horizontal or vertical direction.

Toolbar

Pull-down Dimension Aligned

Keyboard DIMALIGNED

Command Sequence

Command: DIMALIGNED

First extension line origin or press ENTER to

select:(pick P1)

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Second extension line origin: (pick P2)

Dimension line location (Mtext/Text/Angle): (pick a point)

The DIMCONTINUE and DIMBASELINE commands can both be used in conjunction with

DIMALIGNED dimensions.

Changing the Text

The Text option allows you to enter a single line of text and the Mtext option starts the

MTEXT command and enables you to add formatted, multiline text to the dimension. These

options can be used to add descriptions to your dimensions or to modify the measured

distance.

In the example above, the Mtext option has been used to create a multi-line annotation.

When you use this option you will notice that the Multiline Text Editor dialogue already has

some text in the text window. This is the measured dimension and is displayed as "<>". If

you delete this marker the dimension measurement will not appear in the annotation.

If you need to edit dimension text after the dimension is drawn, you can use the DDEDIT

command or the Modify/Object/Text… from the pull-down. If you select a dimension, the

Multiline Text Editor will appear and you can make any necessary changes to the

annotation.

The Radial Dimension Commands

There are two main radial dimension commands,

DIMDIAMETER and DIMRADIUS. Both

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commands result in a similar looking dimension so AutoCAD automatically inserts a "R" to

indicate a radius and the dimension symbol to indicate a dimension.

The Diameter and Radius commands are supplemented by the DIMCENTER command

which can be used to add a center mark to any circle or arc. The DIMDIAMETER and

DIMRADIUS commands do not automatically draw a center mark.

By convention it is usual to dimension full circles using a diameter and arcs (partial

circles) using radius.

The Diameter Dimension Command

You can use the Diameter command to annotate a circle or an arc with a diameter

dimension.

Toolbar

Pull-down Dimension Diameter

Keyboard DIMDIAMETER

Command Sequence

Command: DIMDIAMETER

Select arc or circle: (pick the circumference P1)

Dimension line location (Mtext/Text/Angle): (move the

cursor until you are happy with the text position and

then pick to complete the sequence)

The Radius Dimension Command

The Radius command is identical to the Diameter command except that the dimension

measurement is a radius rather than a dimension and the resulting dimension text is prefixed

with a "R" to indicate radius.

Toolbar

Pull- Dimension Radius

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down

Keyboard DIMRADIUS

Command Sequence

Command: DIMRADIUS

Select arc or circle: (pick the circumference P2)

Dimension line location (Mtext/Text/Angle): (move the

cursor until you are happy with the text position and then

pick to complete the sequence)

Notice that in the illustration above the radius dimension has been positioned inside

the circle. Both diameter and radius dimensions can be positioned either inside or

outside an arc or circle.

The Angular Dimension Command

The Angular command is e used to indicate an angle in almost any situation.

Toolbar

Pull-down Dimension Angular

Keyboard DIMANGULAR

Command Sequence

Command: DIMANGULAR

Select arc, circle, line, or press ENTER: (pick a line)

Second line: (pick another line)

Dimension arc line location (Mtext/Text/Angle): (pick point)

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Move the cursor position until you are happy with the result. Notice that you can

move the cursor to either side of the lines and the angular dimension will change

accordingly.

The Leader Command

The Leader command is used to annotate any point on a drawing.

Toolbar

Pull-down Dimension Leader

Keyboard LEADER

Command Sequence

Command: LEADER

From point: (pick the point to annotate)

To point: (pick vertex point)

To point (Format/Annotation/Undo)<Annotation>:

(pick end point)

To point (Format/Annotation/Undo)<Annotation>:

Annotation (or press ENTER for options): Corner of

MText: building

MText: (to end)

Unlike other dimension commands the leader and annotation text are drawn as

separate objects. So, if you need to move or edit the text, you can do so without

affecting the leader line.

Dimension Styles

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Dimension styles are the main method used to control the way dimensions look. Using styles

you can change the text font, the arrow head style, the relative position of the text, the scale

of dimensions and many other parameters. Styles are created using the DIMSTYLE

command.

Toolbar

Pull-down Dimension Style…

Keyboard DDIM short-cut D

The Dimension Style command can be used to change the appearance of dimensions. The

best method is to create a new style before you start creating dimensions so that you can

leave the STANDARD style as a default option.

You can change styles such as: Linear, Radial, Angular, Diameter, Ordinate and Leader.

Fig. 5.5: Dimension Style Dialogue Box

The Dimension Update Command

The Dimension Update command is used to apply the current dimension style to existing

dimensions. You can use this command to change the style of a dimension. Unlike text

styles, dimension styles do not automatically update when the style is changed. The

UPDATE command must be used to force dimensions to appear in the current text style.

Toolbar

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Pull-down Dimension Update

Keyboard DIM UPDATE

Command Sequence:

Command: DIM

Dim: UPDATE

Select objects: (pick dimension to update)

Select objects: (pick more dimensions or to end)

Dim: (press the escape key, Esc to return to the command prompt)

Part B: The Text Command

Text can be added to an Autocad drawing to create notes and labels on your drawings. There

are two different text commands used to add text to drawings: Text and Mtext.

Text command can be started through:

i. Selecting Text from the Pull-down Menu

Fig. 5.6: Pull-Down Menu Selection <Text>

ii. Draw Toolbar

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Fig. 5.7: Draw Tolbar <A>

iii. Typing at the keyboard

Fig. 5.8: Keyboard entry

Text or Dtext or Single Line Text Command

It is a simple way to add basic text notes. The height and rotation of the text can be quickly

specified and the text can be viewed on the drawing while being typed.

a. Do the text command by following the instructions below:

Command: TEXT

Current text style: "Standard" Text height: 3.0000

Specify start point of text or [Justify/Style]: (pick a point)

Specify height <3.0000>:5 (enter the text height required)

Specify rotation angle of text <0>: (to accept the default)

Enter text: ELECTRICAL ENGINEERING DEPARTMENT

Enter text: POLITEKNIK UNGKU OMAR IPOH

Enter text:

Enter text: (exit text command)

Text displayed using the Single Line Text command.

Notice that each line is separately selectable and independent of the previous line. As each

line is separately editable, this text type is called single line text.

b. Do the following text command by following the instructions below;

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Create a rectangular measuring 150mm length and 15mm width.

Start the text or dtext command:

Current text style: "Standard" Text height: 3.7500

Specify start point of text or [Justify/Style]: J (selection for Justify)

Enter an option [Align/Fit/Center/Middle/Right/TL/TC/TR/ML/MC/MR/BL/BC/BR]:

F (selection Fit)

Specify first endpoint of text baseline: (pick point P1)

Specify second endpoint of text baseline: (pick point P2)

Specify height <3.0000>: 15

Enter text: POLITEKNIK UNGKU OMAR IPOH

Enter text:

Enter text: ( exit text command)

Text displayed using the Single Line Text Command justification

(The text is fixed accordingly to the height of the given box)

c. Do the following text command by following the instructions below;

Create another rectangular measuring 150mm length and 15mm width.

Start the text or dtext command

COMMAND: TEXT

Current text style: "Standard" Text height: 15.0000

Specify start point of text or [Justify/Style]: J (Selection for Justify)

Enter an option [Align/Fit/Center/Middle/Right/TL/TC/TR/ML/MC/MR/BL/BC/BR]:

F (selection for Fit)

Specify first endpoint of text baseline: _from Base point: <Offset>: @5,5

Specify second endpoint of text baseline: _from Base point: <Offset>: @-5,5

Specify height <15.0000>: 5

Enter text: POLITEKNIK UNGKU OMAR IPOH

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Enter text:

Enter text: (exit text command)

Text displayed using the Single Line Text Command justification

(Text is fixed accordingly to height of the text required)

d. Multiline Text

Multiline text is the more advanced text tool within Autocad. The multiline text command

has its own editor, with all the options available that you'd expect to see in a word

processing program. Also, all text on separate lines is treated together, so editing notes and

sentences is simple.

Do the Multiline command by following the instructions below:

Command: Mtext

Current text style: "Standard" Text height: 5

Specify first corner: (pick a point P1)

Specify opposite corner or [Height/Justify/Line spacing/Rotation/Style/Width]: (drag

the cursor and pick a point P2)

A multiline text editor appears on the screen.

Fig. 5.9: Multiline Text Editor

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When a text is entered into the multiline text editor, it will automatically start a

second line when it comes to the edge of the text box we specified. Its similar to

getting to the right hand margin in a text editor.

We can choose the font style, text height, also and also add symbols.

Press the ok button to place the text into the drawing (The text placement will be

justified as set in the properties-justification setting in the text editor.

Text in Autocad is treated like every other object, it can be rotated, mirrored, exploded,

moved layers etc.

Part C: The Linetype

When you first start AutoCAD, the default template has only one linetype is available. This

is the continuous linetype. AutoCAD has many more available, but only loads in one to start

with in order to keep the drawing file size smaller. If you need a different linetype, you must

load it into your current drawing

Instead of creating a new linetype (like you would a layer), you will have to LOAD it into

your drawing.

The linetype command can be started through:

i. Selecting the linetype at the Pull-down Menu <FORMAT>

A Linetype dialogue box appears on the screen.

Fig. 5.10: Pull-down menu Selection <Linetype>

ii. Object Properties Toolbar <By layer>

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Fig. 5.11:Object Properties Toolbar <By layer>

iii. Typing at the keyboard

Fig. 5.12: Keyboard command <linetype>

A Linetype Manager dialog box appear as in Fig. 5.11

Fig 5.13: A Linetype Manager dialogue box

Click the Load Button and a Load or Reload Linetypes dialogue box appears.

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Fig. 5.14: A Load or Reload Linetypes dialogue box

Notice that AutoCAD is giving you a choice of different linetypes as defined in the acad.lin

file. Scroll through the list to see what options you have available. You'll see the most

common ones (hidden, center, etc) as well as some that are only for certain applications.

Click on the Hidden linetype and then press OK.

Part D: EXERCISE

1. Create a new drawing space using the Metric measurement.

2. Set the drawing limits to A4 paper size.

3. Display the grid to the extent of the drawing limits.

4. Redraw all the figures in Fig. 5.15, Fig. 5.16 and Fig. 5.17 below.

5. Give dimensions to the figures drawn.

6. Save the drawing file and exit AutoCAD.

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Fig. 5.15

Fig.5.16

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Fig. 5.17

DISCUSSION:

1. What is the difference between Text Command and Mtext Command?

…………………………………………………………………………………………

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…………………………………………………………………………………………

2. Draw the symbols for these following linetypes:

a. Hidden line -

b. Center line -

c. Phantom line -

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(2 Marks)

(3 Marks)

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QUESTIONS :

1. Why must you use the OSNAP points when making dimensions to an object?

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REFLECTION:

At the end of this practical work, I have learnt that:

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(3 Marks)

(2 Marks)