autocad 2d module 08 pdf

8/14/2019 Autocad 2d Module 08 PDF

1/15

Learning Outcomes:

AutoCAD Self-paced Learning Modules

AutoCAD 2DModule 8

Object Snap

When you have completed this module, you wil l be able to:

1. Describe object snap, AutoSnap, manual object snap modes, and the object snap

modes for a line, circle, and an arc.2. Describe and apply the OSNAP command to set the object snap modes, how to enable

and disable object snap, and use object snap to complete drawings.

Object SnapObject snap allows you to immediately locate and attach to a predefined snap location(s) on an

existing object in the drawing. All AutoCAD objects have at least one object snap location andyou will learn them all as you work your way through the AutoCAD Modules. In this module,the objects line, circle, and arc are addressed.

Using object snap allows you to draw quickly and accurately using existing geometry in the

drawing. You do this without having to know the coordinates of those objects. Object snap isone of the most important features in any CAD system.

Study Figure 8-1, 8-2, and 8-3, they show the object snap modes for a line, circle and an arc.

Notice how a line has 3 locations you can attach to while circles and arcs have 5 each. Whenrequested, AutoCAD will find the exact locations on existing objects.

Object Snap Modes for a Circle

Mode

Center

Quadrant

Abbreviations

Cen

Quad

Icon Marker

Figure 8-1

The AutoCAD Object

Object Snap

Object Snap Modes for a Circle

The CAD Guys Ltd. Copyright 1993 - 2007 Module 8
http://www.abbyy.com/buyhttp://www.abbyy.com/buy


2/15

8 - 2 AutoCAD Self-paced Learning Modules - AutoCAD 2D - Revised 2007-04-11

Object Snap Modes for an Arc

Mode

Endpoint

Midpoint

Center

Quadrant

Abbreviations

End

Mid

Cen

Quad

Icon Marker

Figure 8-2

The AutoCAD Object

Mode

Endpoint

Midpoint

Abbreviations

End

Mid

Object Snap Modes for an Arc

Object Snap Modes for a Line

Icon Marker

Figure 8-3

Object Snap Modes for a Line

The AutoCAD Object

AutoCAD Command: OSNAPThe OSNAP command is used to set the object snap modedefaults.

Shortcut: OS

AutoSnap

AutoSnap is a visual aid to help you see and use object snap modes more efficiently. It allows

you to set the object snap modes you want AutoSnap to find. It can be enabled or disabled atanytime you choose. AutoSnap displays a markerand a tool tip when you move your cursorover a object snap location that has been set to be found within the command.

Object Snap The CAD Guys Ltd. Copyright 1993 - 2007 Module 8


3/15

AutoCAD Self-paced Learning Modules - AutoCAD 2D - Revised 2007-04-11

Geometry Lesson

Finding the Center of a Square or Rectangle

Here are two methods to easily and accurately find the center of a

square or a rectangle without knowing their size or doing any math.

Method 1

Step 1: Draw a construction line between any two diagonal cornersby snapping to the endpoints.

Step 2: The midpoint of the construction line you inserted in Step 1

is the center of the square or rectangle.

Step 3: In this step, a circle is inserted at the midpoint of the line.

The circle is exactly in the center of the square or rectangle.

Method 2

8 - 3

Object Snap

Step 1: Draw a line between the midpoints of two opposite sides

of the rectangle or square.

Step 2: Draw another line between the midpoint of the other

opposite sides of the rectangle or square

Step 3: The midpoint of either line and the intersection of the two

lines is the center of the rectangle or square. One linewould have been enough to find the center but quite often

you need a center line in both directions.

The function key F3 toggles the AutoSnap feature off and on. Althoughthere are other ways to do this, try to get into the habit of using F3 as it willgreatly improve your drawing speed.

The CAD Guys Ltd. Copyright 1993 - 2007 Module 8
http://www.abbyy.com/buyhttp://www.abbyy.com/buyhttp://www.abbyy.com/buy


4/15


Using Osnap

Step 1 Start a new drawing using the template Module Template A.

Step 2 Save and name the drawing

AutoCAD 2D Workalong 08-1.

Step 3 Create layer Object and Construction as

shown in Figure Step 3.

Step 4 Move the cursor on the OSNAP icon in the

status bar. Right click the mouse and in the right-click menu, click Settings as shown in FigureStep 4.

Step 5 This will openthe Drafting Settingsdialogue box as shownin Figure Step 5. Enablethe Object Snap tab andthe Object Snap modesbox, enable the modesto match Figure Step 5.Click OK to close thedialogue box.

Step 6 Enable osnapmode by pressing F3.

Notice how the OSNAP item in the status barwill enable as shown in Figure Step 6A.Press F3 again and note how osnap mode isdisabled as shown in Figure Step 6B.

...continued on page 8-5

Figure Step 3

Figure Step 4

Figure Step 5

Figure Step 6A

Figure Step 6B



5/15


Using Osnap - Continued

Step 7 Set layer Construction asthe current layer and then enter thecommands shown below to draw the

8 - 5

four steps of the object as shown inFigure Step 7.

(Draw on layer Construction.)

Command: LSpecify first point: 5.5,6

Specify next point or [Undo]: @0,2Specify next point or [Undo]: @-3,0Specify next point or [Undo]: @0,-2

Specify next point or [Undo]: C

Command: (Press F3 to enable Osnap mode.)Command: L

Specify first point: (end) P1(Snap to the end of the line.)

Specify next point or [Undo]: (end) P2(Snap to the end of the opposite line.)

Specify next point or [Undo]:Command: CSpecify center point for circle or [3P/2P/Ttr (tan tanradius)]: (mid) P3

(Snap to the midpoint of the line.)

Specify radius of circle or [Diameter] : D

Specify diameter of circle: : .75Command: ERASESelect objects: P4 1 foundSelect objects:


Object to be drawn

Figure Step 7



6/15



Command: L (See Figure Step 7B)

Specify first point: (cen) P5(Snap to the center of the circle)

Specify next point or [Undo]: (end) P6Specify next point or [Undo]:Command: LSpecify next point: (cen) P5

Specify next point or [Undo]: (end) P7

Specify next point or [Undo]:Command: LSpecify next point: (cen) P5Specify next point or [Undo]: (end) P8

Specify next point or [Undo]:Command: LSpecify next point: (cen) P 5Specify next point or [Undo]: (end) P9

Specify next point or [Undo]:Command: CSpecify center point for circle or [3P/2P/Ttr (tan tanradius)]: (mid) ofP10Specify radius of circle or [Diameter]: D Specify diameter

of circle: .25

Command: CSpecify center point for circle or [3P/2P/Ttr (tan tan radius)] (mid) P11Specify radius of circle or [Diameter] :Command: C

Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: (mid) P12

Specify radius of circle or [Diameter] :Command: CSpecify center point for circle or [3P/2P/Ttr (tan tan radius)]: (mid) P13

Specify radius of circle or [Diameter] :Command: L (See Figure Step 7C)

Specify first point: (quad) P14Specify next point or [Undo]: (quad) P15Specify next point or [Undo]:Command: L

Specify first point: (quad) P16Specify next point or [Undo]: (quad) P17

(Inserting the line from quad to quad )

Specify next point or [Undo]:Command: LSpecify first point: (quad) P18Specify next point or [Undo]: (quad) P19

Specify next point or [Undo]:Command: L

Specify first point: (quad) P20

Figure Step 7B

Specify next point or [Undo]: (quad) P21Specify next point or [Undo]:Command:


Figure Step 7C



7/15



8 - 7

Step 8 Without entering a command, individually select the objects that you want to resideon layer Object as shown in Figure Step 8A. While the objects are selected, pull down thelayer toolbar list and click the name Object. After you select the name, cl ick inside the graphicwindow and press Esc to clear the selected objects. Your drawing should now appear as Figure Step8B.

Figure Step 8A

Figure Step 8B

Step 9 Pull down the layer list agin and freezelayer Construction as shown in Figure Step 9A.Your drawing is complete and should appear asshown in Figure Step 9B.

Figure Step 9A

Figure Step 9B

Step 10 Save and close the drawing.

Object Snap The CAD Guys Ltd. Copyright 1993 - 2007

Completed

Drawing

Module 8


8/15


Manual Object Snap Modes

You can also enter manual object snap modes inside of any command that uses them. This

can be a handy feature for modes you do not use very often. It is also a good way to override

the current settings and force AutoCAD to find just the mode you want. For example:

Command: LINESpecify first point: end ofP1(Inside the LINE command, you must start the next line at the end of an existing Line. Instead of

using AutoSnap, enter the mode end to AutoCAD's prompt and it asks of. When a line is picked,AutoCAD will snap to the closest endpoint on that line. )

orCommand: CIRCLE

Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: mid ofP2(Here, in the CIRCLE command, the snap mode mid is entered and AutoCAD responds of. Pickan existing object and AutoCAD will snap to its midpoint.)

When using the manual object snap method, the Object Snap toolbar can

be used rather than typing the object snap modes. A tool tip will open as

you pass your cursor over each icon to see what mode each onerepresents.

Geometry Lesson

Using Construction Objects

The best way to construct some

drawings is to draw constructionobjects to aid you. You will seemore and more drawings like thisin future lab exercises.Construction objects are objectsthat you draw to be used forconstruction only and will not bepart of the finished drawing. It is important to save those objects for later use or to see how theconstruction was preformed.

From this point forward, in all lab exercises, you will be asked to create a layer named Construction,color 253. Draw all construction objects on this layer and do not delete them. When you have

finished the drawing, freeze the layer Construction. When required, simply thaw the layerConstruction to gain access to the construction objects. See the drawing above. The object on theleft has all the construction objects displayed and on the right, they are frozen.

Note: Some drawings do not require any construction objects to be drawn.




9/15


Using Construction Objects - continued

Author's Comments:

There are many ways to draw using AutoCAD and it seems that each CAD operator has his/her own

8 - 9

method. There is no right or wrong way as long as you can draw what you want accurately.Layers are used extensively in industry to keep the drawings standard and consistent withinthe company. Layers are also used when you are plotting the drawings to achievelineweight as you will see later in the course.

I recommend using a construction layer. The construction layer contains objects that are used to

construct the object being drawn but in the end, are not part of the actual drawing itself.After you complete the drawing, you can freeze the construction layer so it cannot be seenby others. If in the future you have to make revisions to the drawing, you can thaw theconstruction layer and use the construction objects. That means you do not have to redrawthem which will save you time. Some drawings do not have any construction objects whileother have a lot of them.

As an AutoCAD instructor it also help me to see how the student is constructing the object. This is

especially true for online students. When I can't observe a student drawing, I use theconstruction layer to help me see the students techniques.

When I draw in AutoCAD, I draw all objects on the construction layer and complete thedrawing. After I finish it, I change the layers of the objects I want to be part of the finisheddrawing. The lines and circles that are left, are the construction objects. There are many

ways to draw and each person has to choose his/her method that works the best for them.As you work your way through the modules, you will learn many techniques and drawingmethods. You will develop your own way of drawing that suits you best.

Whenever possible, disable the AutoSnap feature. When it is enabled at

the wrong time during the drawing process, it can cause drawing problems.It is important to use object snap whenever possible but disable it whenyou do not require it. It can be toggled off and on with the F3 key.

The Key Principles in Module 8

1. Object snap is one of the most important features in any CAD system. Use object snap

modes to quickly and accurately draw using existing geometry in the drawing.

2. The function key F3 toggles the AutoSnap feature off and on.

3. Use geometry and osnap rather then math to find the centers of squares or rectangles.4. You can override or force AutoCAD to snap to a snap location on an object by manually

entering the osnap mode in the command line.

5. Turn AutoSNAP off when you aren't using it.

6. Draw construction objects on layer Construction and freeze it after you complete the

drawing.



10/15


Lab Exercise 8-1

Drawing Specifications

Time Allowed: 30 Min.

Name Template Units Text Style Font

AutoCAD 2D Lab 08-1 Module Template A Inches N/A N/A

Note: Color, Linetype, and Lineweight are all < ByLayer< unless otherwise instructed.

Layering Scheme

Objects on Layer Name Color Linetype Lineweight

Construction Objects

Lines and Arcs

Circles

Instructions:

Construction

Object 1

Object 2

253

Red

Blue

N/A

N/A

N/A

N/A

N/A

N/A

1. Setup the layers using the Layering Scheme shown above.2. Draw the object shown below using the layering scheme above. In this

drawing, lines and arcs are on layer Object 1 and circles are on layer Object 2.Lines and arcs should display red and circles should display blue.3. Draw all construction objects on layer Construction.4. Check your drawing with the key. The key name is the same as the drawing

name shown above. If you have trouble doing this, redo Module 3.5. If you have any errors, correct your drawing.6. Turn layer Key off and freeze layer Construction.7. Save and close the drawing. Completed

Drawing



11/15


Construction Technique

The following steps are the construction technique suggested by the author to help you learn how to

8 - 11

construct objects using AutoCAD. It is only the suggested method and if you can complete the drawingaccurately using a different construct technique, that is what is important. You may want to compare yourconstruction technique with the authors.

Construction Hints

Do your best to complete the lab exercise drawing without using the following

hint(s). If you get stuck and can't complete it on your own, use the followinghint(s) to help you.

Hint 1 Use osnap modes and snap to as many coordinate locations

as possible rather then entering XY coordinates on thekeyboard.

Example 1:

Command: ARC

Specify start point of arc or [Center]: CSpecify center point of arc: (end) P1Specify start point of arc: (end) P2Specify end point of arc or [Angle/chord Length]: ASpecify included angle: 60Command:

Example 2:

Command: LINESpecify first point: (end) P3Specify next point or [Undo]: (end) P4Specify next point or [Undo]:Command:




12/15


Lab Exercise 8-2



Name Template Units Text Style Font

AutoCAD 2D Lab 08-2 Module Template C Inches N/A N/A


Layering Scheme



Lines and Arcs

Circles

Instructions:

Construction

Object 1

Object 2

253

Red

Blue

N/A

N/A

N/A

N/A

N/A

N/A

1. Setup the layers using the Layering Scheme shown above.2. Draw the object shown below using the layering scheme above. In this

drawing, lines and arcs are on layer Object 1 and circles are on layerObject 2. Lines and arcs should display red and circles should display blue.3. Draw all construction objects on layer Construction.4. Check your drawing with the key. The key name is the same as the drawing

name shown above. If you have trouble doing this, redo Module 3.5. If you have any errors, correct your drawing.6. Turn layer Key off and freeze layer Construction.7. Save and close the drawing.

Completed

Drawing



13/15


Construction Techniques


8 - 13


Construction Hints

Do your best to complete the lab exercise drawing without using

the following hint(s). If you get stuck and can't complete it on yourown, use the following hint(s) to help you.

Hint 1

Construction Objects(Keep in mind that arcs are constructed

counterclockwise in AutoCAD.)Command: ARCSpecify start point of arc or [Center]: CSpecify center point of arc: (end) P1Specify start point of arc: @-1.5,0

(This sets the radius and the direction of the start

point.)Specify end point of arc or [Angle/chord Length]: (end) P2Command:

Figure Hint 1

Hint 2

Command: ARCSpecify start point of arc or [Center]: CSpecify center point of arc: (mid) P3

Specify start point of arc: (mid) P4Specify end point of arc or [Angle/chord Length]: (mid) P5

(Make sure you construct the arc counterclockwise.)Command:

Figure Hint 2



14/15


Lab Exercise 8-3



Name

AutoCAD 2D Lab 08-3

Template

N/A

Units

N/A

Text Style

N/A

Font

N/A


Layering Scheme



Lines and Arcs

Circles

Instructions:

Construction

Object 1

Object 2

253

Red

Blue

N/A

N/A

N/A

N/A

N/A

N/A

1. Open the drawing AutoCAD 2D Lab 08-2.2. Using the SAVEAS command, save it with the name AutoCAD 2D Lab 08-3.

3. Turn off all the layers except for layer Key. If the magenta block (overlay)from Lab 08-2 displays, select it and press the delete key. Turn all of theother layers back on.

4. Complete the object below by adding and erasing objects to match thedrawing object shown below.

5. Draw all construction objects on layer Construction.6. Check your drawing with the key. The key name is the same as the drawing

name shown above. If you have trouble doing this, redo Module 3.7. If you have any errors, correct your drawing.8. Turn layer Key off and freeze layer Construction.9. Save and close the drawing.

Completed

Drawing



15/15


Construction Techniques


8 - 15


Construction Hints

Do your best to complete the lab exercise drawing without using

the following hint(s). If you get stuck and can't complete it on yourown, use the following hint(s) to help you.

Hint 1


Figure Hint 2

Hint 2

Figure Hint 2


autocad 2d module 08 pdf

Documents