AutoCAD® 2009 For Dummies®

Chapter 14. Entering New Dimensions

In This Chapter

• Understanding dimension parts and types

• Using dimension styles from other drawings

• Creating and modifying your own dimension styles

• Choosing a dimensioning method

• Drawing and modifying annotative dimensions

• Editing dimensions

In drafting — either CAD or manual drafting — dimensions are special text labels with attached lines that together clearly indicate the size of something. Although it's theoretically possible to draw all the pieces of each dimension by using AutoCAD commands such as LINE and MTEXT, dimensioning is so common a drafting task that AutoCAD provides special commands for doing the job more efficiently. These dimensioning commands group the parts of each dimension into a convenient, easy-to-edit package. Even better, as you edit an object — by stretching it, for example — AutoCAD automatically updates the measurement displayed in the dimension text label to indicate the object's new size, as shown in Figure 14-1. And perhaps best of all, AutoCAD 2009's annotative dimensions automatically change their size as you change the annotation scale on the model tab or the viewport scale in a layout. I explain the general principles of annotative objects in Chapter 13; in this chapter, I take a closer look at annotative dimensions.

AutoCAD controls the look of dimensions by means of dimension styles, just as it controls the look of text with text styles, and tables with table styles. (AutoCAD also uses text styles to control the appearance ...