Dimensioning Non-orthogonal Objects

Dimensioning Non-orthogonal Objects
So far, you’ve been reading about how to work with linear dimensions. You can also dimension
non-orthogonal objects, such as circles, arcs, triangles, and trapezoids. In this section, you’ll practice dimensioning a non-orthogonal object.
For the following exercises, you’ll use a drawing of a hexagonal-shaped window. Open the 12awind.
dwg file from the sample files; metric users should open the 12a-wind-metric.dwg file. You
can use this file to follow along with the next set of exercises.

Adding a String of Dimensions with a Single Operation

Adding a String of Dimensions with a Single Operation
AutoCAD provides a method for creating a string of dimensions by using a single operation. The
Qdim command lets you select a set of objects instead of having to select points. The following exercise demonstrates how the Qdim command works:
1. If you haven’t done so already, zoom out so you have an overall view of the Unit floor plan.
2. Choose Dimension  Quick Dimension, or click Quick Dimension on the fly-out of the
Dimensions control panel.
3. At the Select geometry to dimension: prompt, place a selection window around the
entire left-side wall of the unit.
4. Press ↵ to finish your selection. The following prompt appears:
Specify dimension line position, or [Continuous/Staggered/Baseline/Ordinate/Radius/Diameter/ datumPoint/Edit/seTtings] :
5. Click a point to the left of the wall to place the dimension. A string of dimensions appears,
displaying all the dimensions for the wall.



6. When you’ve finished reviewing the results of this exercise, exit the file without saving it.
The prompt in step 4 indicates several types of dimensions you can choose from. For example,
if you want the dimensions to originate from a single baseline, you can enter B↵ in step 4 to select the Baseline option.
The Qdim command can be a time-saver when you want to dimension a wall quickly. It may not
work in all situations, but if the object you’re dimensioning is fairly simple, it can be all you need.
TIP In this exercise, you used a simple window to select the wall. For more complex shapes, try
using a crossing polygon selection window. See Chapter 2 for more on crossing polygons.

Adding or Removing the Alternate Dimensions
You may eventually encounter a drawing that contains alternate dimensions, as shown in some of the figures earlier in this chapter. You can remove those alternate dimensions by turning off the alternate dimension features. Here’s how it’s done:
1. Choose Dimension  Dimension Style, or enter D↵ to open the Dimension Style Manager
dialog box.
2. Select the style that uses the alternate units. In the Styles list box, choose Modify.
3. Click the Alternate Units tab.
4. Click the Display Alternate Units check box to remove the check mark.
5. Click OK, and then click Close to close the Dimension Style Manager dialog box.
The dimensions that use the style you just edited change to remove the alternate dimensions.
You can also perform the reverse operation and add alternate dimensions to an existing set of
dimensions. Follow the steps shown here, but instead of removing the check mark in step 4, add the check mark, and make the appropriate setting changes to the rest of the Alternate Units tab.

Using Osnap While Dimensioning
When you pick intersections and endpoints frequently, as you do during dimensioning, it can be inconvenient to use the Osnap shortcut menu. If you know you’ll be using certain osnaps frequently, you can use Running Osnaps (See “The Osnap Options” in Chapter 3 for more on setting up Running Osnaps).
After you’ve designated your Running Osnaps, the next time you’re prompted to select a point, the selected osnap modes are automatically activated. You can still override the default settings by using the Osnap shortcut menu (Shift+click the right mouse button).
There is a drawback to setting a Running Osnap mode: When your drawing gets crowded, you can end up picking the wrong point by accident. However, you can easily toggle Running Osnap mode off by clicking Osnap in the status bar or by pressing F3.

Associating Dimensions with Objects

Associating Dimensions with Objects
You’ve seen how dimensions and the objects they’re associated with can move together so the
dimension remains connected to the object. In the process of editing a drawing, dimensions may
lose their association with objects; so, you may need to re-create an association between a dimension and an object. The following steps show you how this is done:
1. Choose Dimension  Reassociate Dimensions. You can also type Dimreassociate↵ at the
Command prompt.
2. At the prompt
Select dimension to reassociate
Select Objects:
select the dimension that you want to reassociate with an object, and then press ↵.
3. At the Specify first extension line origin or [Select object] : prompt,
an X appears at one of the dimension’s definition points.



4. Use the Endpoint osnap, and click the end of the object you want to have connected to the
definition point indicated in step 3.
5. An X appears at the dimension’s other definition point. Use the Endpoint osnap again, and
click the other endpoint of the object you want associated with the dimension. You now have
the dimension associated with the endpoints of the object.
In step 3, you see an X at the location of a dimension definition point. If the definition point is
already associated with an object, the X appears with a box around it. The box is a reminder that the definition point is already associated with an object and that you’ll be changing its association. In this situation, you can press ↵ to switch to the dimension’s other definition point.


Also in step 3, you have the option to select an object. This option enables you to associate the
dimension with an entire object instead of with just one endpoint. If you type S↵ at that prompt in step 3, you can then select the object you want to associate with the dimension. The dimension
changes so that its definition points coincide with the endpoints of the object. The dimension
remains in its original orientation. For example, a vertical dimension remains vertical even if you
associate the dimension with a horizontal line. In this situation, the dimension dutifully dimensions the endpoints of the line but shows a distance of zero.
TIP You can remove a dimension’s association with an object by using the Dimdisassociate command. Type Dimdisassociate↵ at the Command prompt, select the dimension(s), and then press ↵.

Editing Dimensions and Other Objects Together.....

Editing Dimensions and Other Objects Together
It’s helpful to be able to edit a dimension directly by using its grips. But the key feature of AutoCAD’s dimensions is their ability to automatically adjust themselves to changes in the drawing.
To see how this works, try moving the living room closer to the bathroom wall. You can move
a group of lines and vertices by using the Stretch command and the Crossing option:
1. Click the Stretch tool in the Modify toolbar, or type S↵ and then C↵. You’ll see the
following prompts:
At the Select objects to stretch by crossing-window or crossing-polygon...
Select objects: C
Specify first corner:
2. Pick a crossing window, as illustrated in Figure 12.9, and then press ↵ to confirm your
selection.


3. At the Specify base point or Displacement : prompt, pick any point
on the screen.
4. At the Specify second point or : prompt, enter
@2´<90↵ to move the wall 2´ in a 90° direction. The wall moves, and the dimension text changes to reflect the new dimensions, as shown in Figure 12.10.


5. After viewing the result of using the Stretch tool, click the Undo button in the toolbar or type U↵ to change the drawing back to its previous state. You can also use the Mirror, Rotate, and Stretch commands with dimensions. The polar arrays also work, and you can use Extend and Trim with linear dimensions. When you’re editing dimensioned objects, be sure to select the dimension associated with the object being edited. As you select objects, using the Crossing Window (C) or Crossing Polygon (CP) selection option helps you include the dimensions. For more on these selection options, see Chapter 2. TIP If a hatch pattern or solid fill completely covers a dimension, you can use the Draworder command to have AutoCAD draw the dimension over the hatch or solid fill. See Chapters 7, 14, and 18 for more on various uses of the Draworder command. Modifying the Dimension Style Settings by Using Override
In the “Moving Fixed Dimension Text” section, you used the Properties palette to facilitate the moving of the dimension text. You can also choose Dimension  Override (Dimoverride command) to accomplish the same thing. The Override option enables you to change an individual dimension’s style settings.
Here’s an example that shows how you can use the Override option in place of the Properties
palette in the first exercise of the “Moving Fixed Dimension Text” section:
1. Press the Esc key twice to make sure you aren’t in the middle of a command. Then, choose Dimension  Override from the drop-down menu.
2. At the next prompt Enter dimension variable name to override or [Clear overrides]: type Dimfit↵.
3. At the Enter new value for dimension variable <3>: prompt, enter 4↵. This has the same
effect as selecting Move Text, Add Leader from the Fit option of the Properties palette.
4. The Enter dimension variable name to override: prompt appears again, enabling you to
enter another dimension variable. Press ↵ to move to the next step.
5. At the Select objects: prompt, select the dimension you want to change. You can select a group
of dimensions if you want to change several dimensions at once. Press ↵ when you’ve finished with your selection. The dimension settings change for the selected dimensions.
As you can see from this example, the Dimoverride command requires that you know exactly which dimension variable to edit in order to make the desired modification. In this case, setting the Dimfit variable to 4 lets you move the dimension text independently of the dimension line. If you find the Dimoverride command useful, consult Appendix C to determine which system variable corresponds to the Dimension Style dialog box settings.

Changing Style Settings of Individual Dimensions

Changing Style Settings of Individual Dimensions
In some cases, you have to change an individual dimension’s style settings in order to edit that
dimension. For example, if you try to move the text of a typical linear dimension, you may find
that the text and dimension lines are inseparable. You need to make a change to the dimension
style setting that controls how AutoCAD locates dimension text in relation to the dimension line.
This section describes how you can change the style settings of individual dimensions to facilitate
changes in the dimension.
TIP If you need to change the dimension style of a dimension to match that of another, you can
use the Match Properties tool. See Chapter 7 for details on how to use this tool.

Moving Fixed Dimension Text
You’ve seen how dimension text is attached to the dimension line so that when the text is
moved, the dimension line follows. You may encounter situations in which you want to move
the text independently of the dimension line. The following steps show how you can separate
dimension text from its dimension line. These steps also show how you can change a single
dimension’s style settings:
1. Click the dimension you want to edit, to expose its grips.
2. Right-click, and choose Properties from the shortcut menu to open the Properties palette.
3. Scroll down the list of properties until you see the Fit category. If you don’t see a list of
options under Fit, click the downward-pointing arrow to the right to display a new set
of options.
4. Scroll farther down the list until you see the Text Movement option to the right of the Text
Movement listing, and then click this option.
5. Click the arrow that appears next to the Keep Dim Line With Text listing to open the dropdown
list; then, select the Move Text, Add Leader option.

6. Close the Properties palette.

In the Properties palette, the Move Text, Add Leader option in the Fit category lets you move the dimension text independently of the dimension line. It also draws a leader from the dimension line to the text. Another option, Move Text, No Leader, does the same thing but doesn’t include a leader.
You can also set these options for a dimension style by using the Text Placement options in the Fit tab of the New Dimension Style or Modify Dimension Style dialog box.
As you can see from these steps, the Properties palette gives you access to many of the settings
you saw for setting up dimension styles. The main difference here is that the Properties palette
affects only the dimensions you’ve selected.
In a previous exercise, you changed the format setting of a single dimension after it was placed.
These settings can be made a standard part of your Architectural dimension style by using the
Modify button in the Dimension Style Manager dialog box.

TIP If you have multiple dimension styles and you want to change an existing dimension to the currentdimension style, use the Dimension Update tool. Choose Dimension Update on the Dimensionscontrol panel, or choose Dimension  _Update from the drop-down menu. Then, select the dimensionsyou want to change, and press ↵. The selected dimensions will be converted to the current style.
Rotating and Positioning Dimension Text
Once in a while, dimension text works better if it’s kept in a horizontal orientation, even if the dimension itself isn’t horizontal. To rotate dimension text, choose Dimension  Align Text  Angle, select the dimension text, and then enter an angle or select two points to graphically indicate an angle. You can also enter 0↵ to return the dimension text to its default angle.
If you need to move the dimension text to the left, center, or right of the dimension line, you can use the Left, Center, or Right option under the Dimension  Align Text menu options.

Using Grips to Make Minor Adjustments to Dimensions

Using Grips to Make Minor Adjustments to Dimensions
The definition points, whose location you can see through their grips, are located on their own
unique layer called Defpoints. Definition points are displayed regardless of whether the Defpoints
layer is on or off. To give you an idea of how these definition points work, try the following exercises, which show you how to directly manipulate the definition points.
In this exercise, you’ll use coordinates to move a dimension line:
1. With the grips visible, click the grip near the dimension text.
TIP Because the Defpoints layer has the unique feature of being visible even when turned off, you can use it as a layer for laying out your drawing. While Defpoints is turned off, you can still see objects assigned to it, but the objects won’t plot.
2. Move the cursor around. When you move the cursor vertically, the text moves along the
dimension line. When you move the cursor horizontally, the dimension line and text move
together, keeping their parallel orientation to the dimensioned floor plan.
TIP Here the entire dimension line, including the text, moves. In a later exercise, you’ll see how
you can move the dimension text independently of the dimension line.
3. Enter @9´<0↵. Metric users should enter @275<0↵. The dimension line, text, and dimension
extensions stretch to the new location to the right of the text (see Figure 12.8).



TIP If you need to move several dimension lines, select them all at the Command prompt; then,
Shift+click one set of dimension-line grips from each dimension. After you’ve selected the grips,
click one of the hot grips again. You can then move all the dimension lines at once.
In step 3 of the previous exercise, you saw that you can specify an exact distance for the dimensionline’s new location by entering a relative polar coordinate. Cartesian coordinates work just as well. You can even use object snaps to relocate dimension lines.
Next, try moving the dimension line back by using the Perpendicular osnap:
1. Click the grip at the bottom of the dimension line you just edited.
2. Shift+click the right mouse button, and choose Perpendicular from the Osnap shortcut menu.
3. Place the cursor on the vertical dimension line that dimensions the balcony and click it.
4. Choose View  Zoom All, and then choose File  Save to save this file in its current state.
The selected dimension line moves to align with the other vertical dimension, back to its original
location.

Appending Data to Dimension Text

Let’s see how this works by changing an existing dimension’s text in your drawing:
1. Choose Modify  Object  Text  Edit, or type ED↵.
2. Click the last horizontal dimension you added to the drawing at the top of the screen, to
open the Text Formatting toolbar.



3. Press the End key to place the cursor at the end of the 14´-0˝ text, and then type to face
of stud.
4. Click OK on the Text Formatting toolbar, and then press ↵ to exit the Ddedit command. The
dimension changes to read 14´-0˝ to face of stud.
5. Because you don’t need the new appended text for the tutorial, click the Undo button in the
Standard toolbar to remove the appended text.

TIP In this exercise, you were able to edit only a single dimension. To append text to several
dimensions at once, you need to use the Dimension Edit tool. See the “Making Changes to MultipleDimensions” sidebar in this chapter for more on this command.
If you need to restore the original dimension text for a dimension whose value has been completelyreplaced, you can use the steps shown in the previous exercise, but in step 3, replace the textwith the <> bracket symbols.
You can also have AutoCAD automatically add a dimension suffix or prefix to all dimensions,
instead of just a chosen few, by using the Suffix or Prefix option in the Primary Units tab of the NewDimension Style or Modify Dimension Style dialog box. See Appendix C for more on this feature.
AutoCAD provides the associative dimensioning capability to automatically update dimension textwhen a drawing is edited. Objects called definition points determine how edited dimensions are updated.
The definition points are located at the same points you pick when you determine the dimension
location. For example, the definition points for linear dimensions are the extension line origins. The definitionpoints for a circle diameter are the points used to pick the circle and the opposite side of the circle.
The definition points for a radius are the points used to pick the circle, plus the center of the circle.
Definition points are point objects. They’re difficult to see because they’re usually covered by
the feature they define. You can, however, see them indirectly by using grips. The definition pointsof a dimension are the same as the dimension’s grip points. You can see them by clicking a dimension.
Try the following:

1. Make sure the Grips feature is turned on. (See Chapter 2 to refresh your memory on the
Grips feature.)
2. Click the longest of the three vertical dimensions you drew in the earlier exercise. You’ll see
the grips of the dimension, as shown in Figure 12.7.

Making Changes to Multiple Dimensions
You can use the Dimension Edit tool to quickly edit existing dimensions. This tool gives you the ability to edit more than one dimension’s text at one time. One common use for the Dimension Edit tool is to change a string of dimensions to read Equal instead of showing the actual dimensioned distance. The followingexample shows an alternative to using the Properties palette for appending text to a dimension:
1. Type Ded↵.
2. At this prompt Enter type of dimension editing [Home/New/Rotate/Oblique]:
type N↵ to use the New option. The Multiline Text Editor opens, showing 0 in the text box.
3. Use the arrow keys to move the cursor behind or in front of the 0, and then enter the text you wantto append to the dimension. Or, you can remove the 0 and replace the dimension with your text.
4. Click OK.
5. At the Select objects: prompt, pick the dimensions you want to edit. The Select objects:
prompt remains, enabling you to select several dimensions.
6. Press ↵ to finish your selection. The dimension changes to include your new text or to replace the existing dimension text.
The Dimension Edit tool is useful in editing dimension text, but you can also use this tool to make graphicalchanges to the text. Here is a list of the other Dimension Edit tool options:
Home Moves the dimension text to its standard default position and angle.
Rotate Rotates the dimension text to a new angle.
Oblique Skews the dimension extension lines to a new angle. (See the “Skewing Dimension
Lines” section, later in this chapter.)