As you begin to add more dimensions to your drawings, you will find that Auto- CAD will occasionally place a dimension text or line in an inappropriate location, or you may need to make a modification to the dimension text. In this section, you’ll take an in-depth look at how dimensions can be modified to suit those special circumstances that always crop up.
Appending Data to Dimension Text
So far in this chapter, you’ve been accepting the default dimension text. You can append information to the default dimension value, or change it entirely if you need to. At the point when you see the temporary dimension dragging with your cursor, enter T..1. Then, by using the less than «) and greater than (» symbols, you can add text either before or after the default dimension or replace the symbols entirely to replace the default text. The Properties button on the Object Properties toolbar lets modify the existing dimension text in a similar way. Let’s see how this works by changing an existing dimension’s text in your drawing .
- Choose Modify > Text or type ED button.
- Next, click the, last horizontal dimension you added to the drawing at the top of the screen.
- Click the Contents input box, move the cursor behind the <> sign, and then type to face of stud, .
- Click OK. The dimension changes to read “14′-0′ to face of stud.” The text you entered is appended below the dimension text.
- Because you don’t really need the new appended text for the tutorial, click the Undo button in the Standard toolbar to remove the appended text.
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 Dimension Style dialog box: See Appendix 0 for more on this feature.
Locating the Definition Points
AutoCAD provides the associative dimensioning capability to automatically update dimension text when a drawing is edited. Objects called definition points are used to 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 origin and the intersection of the extension line dimension: line. The definition points 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 actually point objects. They are very difficult to see because they are usually covered by the feature that they define. You can, however, see them indirectly using grips. The definition points of a dimension are the same as the dimension’s grip points. You can see them simply by clicking a dimension. Try the following:
- Make sure the Grips feature is turned on (see Chapter 2 to refresh your memory on the Grips feature).
- Click the longest of the three vertical dimensions you drew in the earlier exercise. You will see the grips of the dimension, as shown in Figure 9.7.