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down the Shift key while selecting to remove the objects that you want to exclude from the editing operation.

Pick point 2

Figure 10-4: A crossing selection box, drawn right to left, selects 11 objects that are completely or partially within the box.

Perfecting Selecting

When you edit in command-first mode, you have all the selection options described in the previous section — single object, window box, window polygon, crossing polygon, and crossing box — plus a slew of others. If you type ? and press Enter at any Select objects prompt, AutoCAD lists all the selection options at the command line:

Window/Last/Crossing/BOX/ALL/Fence/WPolygon/CPolygon/

Group/Add/Remove/Multiple/Previous/Undo/AUto/

SIngle/SUbobject/Object

Table 10-1 summarizes the most useful command-first selection options.

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200 Part II: Let There Be Lines

To use any of the command-first selection options at the Select objects prompt, type the uppercase letters indicated in Table 10-1 that correspond to the desired option and press Enter. After you’re finished selecting objects, you must press Enter again to tell AutoCAD that you’ve finished selecting objects and want to start the editing operation.

After you’re finished selecting objects, you must press Enter again to tell AutoCAD that you’ve finished selecting objects and want to start the editing operation. Say . . . is there an echo in here? As a matter of fact, we are repeating ourselves. One of the things that most new AutoCAD users find hardest to remember is the necessity of pressing Enter after you finish selecting objects.

AutoCAD’s selection preview features remove a lot of doubt about which objects you’re selecting. Rollover highlighting displays individual objects with a thick, dashed lineweight as you move the crosshairs over them. Area selection displays a transparent, colored highlight over multiple selections when you use Window and Crossing options. You can enable and disable both features on the Selection tab of the Options dialog box (refer to Figure 10-1).

The following example demonstrates how to use the ERASE command in command-first mode with several different selection options. The selection techniques used in this example apply to most AutoCAD editing commands.

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Chapter 10: Get a Grip on Object Selection 201

1.Open a drawing that contains some objects, or start a new drawing and create some lines, arcs, or circles.

You needn’t be too particular drawing these because you’re going to blow them away in the following steps.

2.Press Esc to make sure that no command is active and no objects are selected.

If any objects are selected when you start an editing command, the command, in most cases, will operate on those objects (selection-first editing) instead of prompting you to select objects (command-first editing). For the reasons that we describe in the section “Commanding and Selecting,” earlier in this chapter, we recommend that you use commandfirst editing style until you’re thoroughly familiar with it. Later, you

can experiment with selection-first editing if you like. (Just reverse the sequence of commanding and selecting that we describe in this chapter.)

3.Click the Erase button on the Home tab’s Modify panel.

AutoCAD displays the Select objects prompt at the command line and, if Dynamic Input is enabled on the status bar, the Dynamic Input tooltip.

4.Select two or three individual objects by clicking each one.

AutoCAD adds each object to the selection set. All the objects you select remain highlighted, and AutoCAD continues to display the Select objects prompt.

5.Specify a window selection box that completely encloses several objects.

Move the crosshairs to a point below and to the left of the objects, click, release the mouse button, move the crosshairs above and to the right of the objects, and click again.

All objects that are completely within the box are selected.

6.Specify a crossing selection box that completely encloses a few objects and cuts through several others.

Move the crosshairs to a point below and to the right of some of the objects, click, release the mouse button, move the crosshairs above and to the left of some of the objects, and click and release again.

All objects that are completely within, cross through, or touch the box are selected. AutoCAD continues to display the Select objects prompt.

7.Type WP and press Enter to activate the WPolygon selection option.

AutoCAD prompts you to pick points that define the selection polygon.

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202 Part II: Let There Be Lines

8.Pick a series of points and press Enter.

Figure 10-5 shows an example. After you press Enter, AutoCAD selects all objects that are completely within the polygon. AutoCAD continues to display the Select objects prompt until you press Enter.

Figure 10-5: Lassoing objects with a WPolygon selects the concentric circles and their center lines.

9.Press Enter to end object selection.

AutoCAD erases all the selected objects and returns to an empty command prompt.

Notice how you could use a combination of object selection methods to build a selection set and then press Enter to execute the command on the selected objects. Most AutoCAD editing commands work this way in command-first mode.

If, after erasing a selection set, you immediately realize that you didn’t really mean to do away with so many objects, you can use the Undo button on the Quick Access Toolbar to restore them all. But AutoCAD has one additional unerase trick up its sleeve — the aptly named OOPS command. When you type OOPS and press Enter, AutoCAD restores the last selection set that you erased — even if you’ve run other commands after ERASE.

The ERASE command isn’t the only way to remove unwanted objects from your drawing. Easiest of all in any workspace is to simply select an item and press the Delete key on your keyboard.

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