utoCAD Tutorial 6:
FOR RELEASE 14

PLEASE READ: ___________

These tutorials were designed to be part of the introductory courses taught by the Graphic Communications Program at NORTH CAROLINA STATE UNIVERSITY. All of the directions used in this, and the other tutorials in this series, assume that you are running AutoCAD Release 14 on an NT system. These directions will only work with Release 14. Other versions may not have the same commands or format.

OBJECTIVES:

After completing this tutorial:

  1. you will be able to add horizontal, vertical, diameter, and radius dimensions to a multiview drawing in AutoCAD;

  2. create continue and baseline dimensions;

  3. understand how to enter and exit AutoCAD's Dimensioning mode;

  4. create a dimensioning style; and

  5. use the Mtext option under the Dimension commands to create counterbore and countersink dimensions.

STEP 1

Now that you have completed a number of drawings in AutoCAD, it is time to learn how to dimension them. You will receive less help in this tutorial since by now you should be able to follow AutoCAD's prompts with little difficulty.

For this tutorial, you will again use a file I created and copy it onto your harddrive or a floppy disk. To access this file, click on the DIM30 file link.
DIM30

After selecting the DIM30 link, one of two things could happen:

  1. the AutoCAD program will launch and open the file,

    OR

  2. a dialogue box will appear.
    If the dialogue box appears, use the appropriate selections to save the file to your harddrive or a floppy disk. Once it is saved to either of these devices, open the file.

Once the DIM30 file is open, the model seen in FIGURE 1 should appear.

FIGURE 1

Use SAVE AS... and rename the original file acadtutor6.

STEP 2

You will begin this tutorial by using Solview and Soldraw to create a 2D Multiview Drawing from the model, so you will need to complete the following:

  1. Load the line types labeled center and hidden.

  2. Complete Solview and leave enough space around your views so you can add dimensions. Your viewports should be close to each other, but fairly large. Look at FIGURE 2 for an estimation of their proper sizes.

    NOTES:

    --To increase the size of a floating viewport, switch to the PAPER side of Paper Space. Click on the edge of the viewport to display the corner handles. Click on a corner handle, so that it turns RED, and drag the corner to a new location.

    --To move a floating viewport, switch to the PAPER side of Paper Space, TURN on ORTHO to constrain the direction the viewport can move and use the Move command to reposition the viewport. Turn off ORTHO when done.

    --To rescale views if they no long match, switch to the MODEL side of Paper Space and use Zoom XP in each viewport.

    --To check alignment of the views, change to the PAPER side of Paper Space and draw a line that connects one element in a view to the same feature in an adjacent view that it should line up with. If they are properly aligned, the line will be straight.

    --To realign views that are out of alignment, switch to the MODEL side of Paper Space and use Mvsetup to realign the views. NOTE: You should use Zoom XP before you align the views. Most likely the reason that they are no longer aligned is that you Zoomed in the Model side of Paper Space.


  3. Now, use the Soldraw command to extract the two-dimensional multiviews.

  4. Add a Front-cen, Top-cen, and Side-cen Layer for center lines and change their color assignment to something OTHER THAN WHITE, so they will print in the proper line thickness.

  5. Change the color of the Front-dim, Top-dim and Side-dim layers so they print in the proper line thickness.

  6. Add center lines where needed (see FIGURE 2).

    The diameter of the small hole associated with the Countersink is 26.
    The diameter of the Countersink is 40.
    The diameter of the small hole associated with the Counterbore is 20.
    The diameter of the Counterbore is 40.

     REMINDER: you must be in the MODEL side of Paper Space to add the center lines.
    You must change your     UCS to match the view.
    You must be in the proper     -cen layer when you add your center lines.
    You can use the     Offset, Extend, and the Layer Status Bar (to change lines to a different layer) to place the center lines.

  7.  Use the Vplayer command to FREEZE the appropriate layers in each viewport so the center lines that should not be displayed are removed. HINT: In the Top Viewport, for instance, you would Freeze the Front-cen and Side-cen layers. You freeze the -cen layers for the viewports that are not active when you use the Vplayer command.

If you need to review these procedures in more detail, look at TUTORIAL 4 again.

The drawing should look like FIGURE 2 when the steps, listed above, are completed.

FIGURE 2

STEP 3

Before adding your first dimension, make sure you are in the MODEL side of Paper Space and leave the Vport layer VISIBLE.

Use ltscale (typed in at a Command: prompt) and change the line scale to .75. This changes the scale of the dashes in the dashed lines (center and hidden).

 

To help you with the selection of the dimensioning commands, you may wish to open the dimensioning toolbar and place it on the AutoCAD window. Remember you will find this under Toolbars... on the View menu.

IMPORTANT NOTE: Once you activate the DIMENSIONING function, AutoCAD stays in this mode until you actively exit it. The word Dim: will replace the usual Command: prompt to indicate you are in this mode. To exit out of Dim: mode you can press the Esc key, type exit at a DIM: prompt, or press Enter until the Command: prompt returns. You cannot use certain commands in the Dim: mode. For instance, you have to exit the Dim: mode to change a UCS or erase.

To add dimensions efficiently, you should create a dimensioning style. Dimension styles can simplify dimensioning by predefining certain dimension formats. The dimension Style... dialogue box is available under the Dimension Menu as Style... or by clicking on the Style button on the Dimension toolbar.

FIGURE 3 shows an example of the Dimension Style dialogue box. Through this box, you have access to the dimensioning Geometry, Format, and Annotation parameters, can create different dimensioning styles, and save them under a name of your choosing. Several dimension styles can be defined and then recalled for later use.

Let's define a new dimensioning style. Notice the current style displayed in the style box is called STANDARD. A plus (+) sign by a style name means that changes have been made to the style parameters, but they have not been made a permanent part of the style by saving the changes. You can either edit an existing style or create a new one. For this tutorial, you will create a style based on the Standard style, but save it under a different name.

 

FIGURE 3

 

To create your new dimensioning style, type NEWSTYLE (with no space between NEW and STYLE) in the window next to the Name: heading.

Click on the button labeled Geometry...

FIGURE 4 provides a look at the Geometry dialogue box.

FIGURE 4

 

Because the model you are using for this tutorial is large, you will have to print it in a 1:2 (half size) scale. To compensate for the print size, you will set the parameters of the dimension style to twice their usual sizes.

In the Geometry dialogue box, make the following changes:

Under Dimension Line -- set Spacing: to 12 (This sets the space between stacked dimensions.)

Under Extension Line -- set Extension: to 6 (This indicates the distance the extension line should extend past the dimension line) and set Origin Offset: to 3 (this determines the gap between the extension line and the element being dimensioned.)

Under Arrowheads -- set Size: to 6 (This sets the arrowhead lengths.)

Under Center -- set Size: to 3 (This sets the length of the lines for a center mark.)

Click in the box beside the heading Scale to Paper Space to select this option. (This makes all of the dimensions the same size in all of the viewports.)

Click on OK to return to the Dimension Style dialogue box.

Next, select the Format button in the Dimension Style dialogue box. Examine FIGURE 5 for an example of the Format dialogue box.

FIGURE 5

 

In this dialogue box, you should use the drop-down menu under Fit: to select the Best Fit option. The possible selections under this drop-down menu are:

Text & Arrow (Always keeps the text and arrows together.)

Text Only (Places only the text between the extension lines.)

Arrows Only (Always places the text outside the extension lines and the arrowheads inside the extension lines.)

Best Fit (Keeps text and arrowheads together unless the space is too small, then the text is placed at the end of a leader line that projects off of the dimension line.)

Leader (Places the dimensions on leader lines.)

No Leader (Places the dimension text above the dimension line without a leader connecting it to the dimension line.)

 NOTE: If you select the Best Fit option, you can edit the position of the dimension text with the Dimension Text Edit command.

Make the settings in your dialogue box look just like the ones in FIGURE 5.

Now, select OK to return to the Dimension Style dialogue box.

Click on the Annotation button. Look at FIGURE 6 for an example of the Annotation dialogue box.

FIGURE 6

 

In this dialogue box, make the following changes:

Set the Text Height: to 6 and the Text Gap: to 1.5. (This sets the distance between the text and the dimension line.)

Click on the Units... button to move to the Units dialogue box.

Find the heading labeled Units and change to the DECIMAL format using the drop-down menu under it. Locate the PRECISION window under the Dimension heading and use its drop-down menu to change the precision level from 0.0000 to 0. (This removes excess zeros after the dimension numbers.)

Click on OK to return to the Dimension Style dialogue box.

The changes you have made, so far, are to the "parent" style. The parent style is the global settings for the dimensions. Once the parent settings are made, you can edit the parameters of the "children" under the parent style. The "children" include Linear, Radial, Angular, Diameter, Ordinate, and Leader dimensions.

Let's edit the Diameter parameters under this parent style. Click on the small circle, to the LEFT of Diameter, to select this "child" and then select the Format button again. In the Format dialogue box, change the Fit: to Leader and check the box beside User Defined, which will let you place the dimension text at a position of your choosing, then click OK. By selecting User Defined, you will be able to control the placement of the diameter dimensions for small holes.

Finally, click the Save button under the Dimension Style window and then OK to exit the Dimension Style dialogue box.

 

You have now created a dimensioning style!

Save!!!

STEP 4

You can now add your first dimension.

IMPORTANT REMINDER: To add dimensions, you must change the UCS to the -dim layer that matches the view. The easiest way to change the UCS is with the View option under the UCS command.

Look at Figure 7 to see an illustration of the first dimension you will add.

Before adding this dimension, make the TOP View active, change to the Top-dim layer, and orient the UCS to the TOP View.
 If you want a better view of the TOP view, change to the PAPER side of Paper Space and use a Window Zoom to enlarge it on the screen. Change back to the MODEL side of Paper Space before adding the dimension.

 

FIGURE 7

The dimension, shown in FIGURE 7, will be added with a Linear dimension.

Activate the Linear dimension command. When the prompt reads: First extension line origin or press ENTER to select:,use the INTERSECTION Osnap and select position A (the first extension line origin) shown in FIGURE 7.

--Prompt: Second extension line origin: Use the INTERSECTION Osnap and select position B (the second extension line origin) shown in FIGURE 7.

IMPORTANT NOTE: Use the Intersection Osnap and not Endpoint to select the extension line origin points for dimensions in a 2D object. If you already have dimensions in place, you can accidentally select the end of an extension line instead of the object line. If your dimension numbers are wrong, you may have done this. All of the numbers in this tutorial should be in whole numbers.

NOTE: Use Osnaps when placing dimensions to be sure they are accurate.

 

The next prompt will ask you to locate the position of the dimension text for this dimension. Because you will print this drawing half size, you will need to place the dimensions approximately 20mm away from the figure, so their distance is approximately 10mm away from the figure when you print. Since the first dimension you are adding is 26mm, this should give you some feel for 20mm. If you want to be more accurate, you can add a line 20mm beyond the figure as a guide and then remove it.

--Prompt: Dimension line location (Mtext/Text/Angle/ Horizontal/ Vertical/Rotated): Select the location for the dimension text by clicking the Left mouse button on the screen.

--Prompt: Dimension text <26>: Press Enter to accept the dimension.

Now, use the same technique to place the rest of the dimensions seen in FIGURE 8.

If you Zoomed to display a larger view of the TOP view, change to the PAPER side of Paper Space, use Zoom Extents, and then Window Zoom around the next view before you add dimensions to it. Be sure to return to MODEL side of Paper Space, change the UCS (outside of the Dim: mode), and the layer to match the view.

 

FIGURE 8

SAVE!

STEP 5

You will now add dimensions using a Continue dimension. A Continue dimension allows you to place dimensions in a continuous row so they are aligned to each other and share an extension line.

Look at FIGURE 9 to see where the first Continue dimension should go. You may want to change to PAPER side of Paper Space and zoom in, but remember to change back to the MODEL side of Paper Space before dimensioning.

FIGURE 9

--Prompt: Dim: or Command: Type dimcont or select the Continue dimension button on the Dimensioning toolbar.

--Prompt: Second extension line origin or RETURN to select: Press Enter.

--Prompt: Select continued dimension: Click on the bottom horizontal dimension (size is 26), in the top view, that you already added to the drawing (see FIGURE 9).

--Prompt: Second extension line origin or RETURN to select: Select the right bottom corner of the rectangular slot (for the 51 dimension).

--Prompt: Dimension text <51>. Press Enter.

--Prompt: Dim: You stay in the DIMENSIONING mode until you type exit at the Dim: prompt and press Enter, press Enter until a Command: prompt returns, or press the Esc key.

ERASING A DIMENSION: If you need to erase a dimension, the Erase command functions the same for dimensions as it does for other elements. Since dimensions are grouped elements, you can click on any part of the dimension, and the whole dimension selects.

NOTE: If you are adding a CONTINUE dimension that will be connected to a dimension you just added, you do not have to identify the dimension the continue dimension will be attached to. For instance, to place the second Continue dimension in the TOP view, you do not have to identify the extension line because you have just placed the 51 dimension it will be attached to. When the prompt reads: Second extension line origin or RETURN to select:, select the left side of the 25 mm slot to place the dimenion. To use this feature of this dimension command, you must select the prior dimension so that its second extension line is the extension line the continue dimension line will connect to, otherwise, the dimension will indicate the wrong value.

Look at FIGURE 9 again to see where you need to add another Continue dimension and perform the same procedures to place this one.

Since you are an intelligent person, I know you have saved lately!

STEP 6

Look at FIGURE 10. This figure shows the RIGHT SIDE view with a vertical dimension added. Use the Linear dimension procedures to add the dimensions shown in this figure.

Zoom in if you wish. Change the UCS and layer.

FIGURE 10

Once you have the vertical dimension in place, examine FIGURE 11 to see where you need to place a Continue dimension adjacent to it.

FIGURE 11

 

Move back to the TOP view so you can add another Linear dimension and two Baseline dimensions. A Baseline dimension allows you to stack dimensions off of a common point of origin. Look at FIGURE 12. The dimensions of 62 and 103 are Baseline dimensions in this illustration.

NOTE: Don't have enough room to place your dimension? Remember you can stretch the size of the viewports.

FIGURE 12

Begin by adding a Linear dimension (30) for the location of the center of the counterbored hole from the top edge of the view. Remember your Layer and UCS.

Now, you are ready to add a Baseline dimension.

At a Command: or Dim: prompt type dimbase, select Baseline on the Dimension Menu, or click on the Baseline button .

Prompt reads: Second extension line origin or RETURN to select: Press Enter.

Prompt reads: Select baseline dimension:. Click on the TOP extension line of the 30 dimension.

Prompt: Second extension line origin or RETURN to select. Use the an Osnap to select the top of the inclined edge on the right side of the Top view (see FIGURE 12).

Prompt: Dimension text <62>:. Press Enter. The dimension appears and is stacked outside of the 30 dimension.

Prompt: Dim: Repeat for the second Baseline dimension of 103.

Prompt: Dim: (you stay in the DIMENSIONING mode until you exit it.)

STEP 7

The three features you will now dimension are the countersink, the counterbore, and the arc.

The countersink will use a Diameter dimension, and its Mtext option, to add the additional text and symbols required to define this feature. The arc (since it is less than 180 degrees) will use a Radial dimension.

Let's begin with the countersink. Look at FIGURE 13 to see the placement of this dimension.

 

FIGURE 13

Select Diameter under the DIMENSION Menu, or type dimdia at a Dim: or Command: prompt line, or click on the Diameter button .

When the Dim: prompt reads: Dimension line location (Mtext/Text/Angle): click on the outside circle of the countersink approximately where the arrow touches it in FIGURE 13, but DO NOT PRESS ENTER. Now, select the Mtext option and press Enter. The Multiline Text Editor dialogue box will appear. See FIGURE 14.

FIGURE 14

Once the Multiline Text Editor dialogue box opens, use the drop-down menu, under Character, to change the font to GDT.

Check the font size to be sure that it is 6 points or change it to 6. (NOTE: You need to check the Font size for every text or symbol component you place in this box since it may change.)

Place your cursor IN FRONT of the brackets (< >) in this dialogue box. The brackets contain the diameter symbol and the size of the outer circle of the countersink although it is not displayed in this window.

With the cursor in front of the the brackets, you can add the diameter symbol and type the diameter value of the smaller circle. To add the diameter symbol, click on the Symbol drop-down menu, on the right side of the dialogue box, and select Diameter. See FIGURE 15.

FIGURE 15

The text %%C should appear in front of the brackets (this is AutoCAD's code for the diameter symbol).

After the %%C, type 20, for the diameter of the smaller hole, followed by a comma.

Next, you need to copy the Countersink symbol from the GDT Character Map dialogue box. To access this box, again click on the Symbol drop-down menu and select Other... See FIGURE 16.

 

FIGURE 16

The Character Map dialogue box displays the dimensioning symbols that you can select in this font. Locate the V (the countersink symbol) and click on it. It should highlight. See FIGURE 17.

FIGURE 17

Click on the Select button, and the countersink symbol should appear in the window next to the heading Character to copy:.

Click on the Copy button, followed by the Close button, to return to the Multiline Text Editor dialogue box.

Insert your cursor just before the < > and press the RIGHT mouse button (a small pop-up menu will appear). Select Paste to add the countersink symbol to the other text (see FIGURE 18).

FIGURE 18

Add a space behind the countersink symbol and then type in 82 and select Degrees on the Symbol drop-down menu. Your text for the countersink hole should look the text in FIGURE 19. Press Enter until the text is placed on your drawing.

FIGURE 19

 

Examine FIGURE 20. Notice where the arc dimension should be placed. Use the Radial dimension (dimrad) and try to place this one on your own. Remember to read the prompts.

FIGURE 20

SAVE!!

STEP 8

The next step is to dimension the counterbore in the TOP view. Remember to change your UCS and layer.

Use the Diameter dimension and Mtext option to make the counterbore text look like the one in FIGURE 21. NOTE: The counterbore symbol is on the LEFT side of the countersink symbol, you just used, in the GDT Character Map dialogue box. The vertical sides of this symbol do not show in the dialogue box, which makes it difficult to find.

FIGURE 21

STEP 9

Look at FIGURE 22. Notice that the position of the 25 for the slot in the bottom of this view has been changed from its original position. Because you selected Best Fit under Fit: in the Dimensioning Style Format dialogue box, it is possible to move this number. To move this text, click on the Edit Text button on the Dimensioning toolbar. Click on the 25, and use your LEFT mouse button to slide it to the new location.

FIGURE 22

Now, look at FIGURE 23, below, and add any dimensions that are not already in the drawing.

 

FIGURE 23

 

 

STEP 9

Your drawing needs a Metric Flag to indicate that it is in the Metric System.

Look at FIGURE 23 again to see approximately where the Metric Flag should be placed. Use dtext to add this text in the PAPER side of Paper Space. The text should be 10mm high. Remember, you are making it twice as big because you are printing the drawing in a 1:2 (half size) scale.

To finish the Flag, add a border line that surrounds it like the one shown in FIGURE 23. HINT: Try using the Rectangle command under the Draw Menu. The rectangle should be about 3mm away from the text.

NOTE: Before bringing in your titleblock, look at your drawing. If there seems to be a great deal of space between the views, use the Move command, while you are in the PAPER side of Paper Space, to move the views closer together. Keep them aligned during the move by turning on the ORTHO option on the Status Line, at the bottom of the AutoCAD screen. The viewports can overlap if necessary, but, obviously, not the dimensions.

Make the Vport layer invisible.

Change to the 0 layer.

Insert your titleblock so it is twice its normal size.

Edit the text as needed.

Plot the file at the appropriate scale. Remember you must use a plot size based on the size you brought in your titleblock. If you inserted the titleblock at a scale of 2, you must plot it out at a scale of 1:2.

Print the file.

CONGRATULATIONS!!!

You have completed the LAST AutoCAD Tutorial for this course, and you have done very well.

I hope you learned a great deal and will explore this program further on your own.

AutoCAD is a registered trademark of AutoDesk, Inc.
AutoCAD Tutorial 6: For Release 14 was written by:
Dr. Alice Y. Scales, Ed.D.
Graphic Communications Program
Department of Mathematics, Science and Technology Education
NORTH CAROLINA STATE UNIVERSITY
With contributions by Russell R. Downs
This work is copyrighted and the property of Alice Y. Scales and is not to be copied without permission of the author.
8/4/98
Revised 6/14/2000

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