AutoCAD For Dummies, 17th Edition

Chapter 8

Preciseliness Is Next to CADliness

IN THIS CHAPTER

Typing coordinates at the keyboard

Getting to know the AutoCAD coordinate systems

Snapping to object features

Using other precision drawing and editing techniques

Drawing precision is vital to good CAD drafting practice, even more than for manual drafting. Accuracy, of course, is vital to both types of drafting. If you’re sketchy on the difference between accuracy and precision, look ahead to the “CAD precision versus accuracy” sidebar in this chapter. If you think CAD managers become tense when you assign properties directly to objects instead of ByLayer (see Chapter 9), wait until someone — I sincerely hope it’s not you — fails to use precision techniques when creating drawings in AutoCAD.

You must draw with precision, at least until you see Chapter 19. Now there’s a teaser for you. Typically, the only point you select at random in a drawing is the first one. Then virtually all line starts and lengths or ends, and all circle and arc centers and radii or diameters, for example, should be specified using exact keyboard input or a suitable object snap.

Controlling Precision

In AutoCAD, a lack of precision makes editing, hatching, and dimensioning tasks much more difficult and time consuming. Keep these facts in mind:

• Small errors in precision in the early stages of creating or editing a drawing often significantly ...