IN THIS CHAPTER

Using command-first editing

Selecting objects with maximum flexibility

Editing with grips

Editing objects is the flip side of creating them, and in AutoCAD you usually spend more time editing objects than drawing them from scratch. That’s partly because the design and drafting process is, by its nature, subject to changes, and also because AutoCAD lets you edit objects cleanly and easily.

Creating an object and then editing it can sometimes be faster than doing it correctly the first time. For instance, placing a circle and then trimming it is often faster than fighting your way through the Arc command’s many options.

Specifying precise locations and distances is as vital to editing objects in AutoCAD as it is when creating them. Become familiar with the precision techniques described in Chapter 8 before you apply the editing techniques described in this chapter to drawings.

Commanding and Selecting

AutoCAD offers three styles of editing, which I list here in order from the most options to the least:

• Command-first editing: Enter an editing command, and then select the objects to edit.
• Selection-first editing: Select objects, and then enter an editing command.
• Direct-object editing: Select an object, and then edit it with grips.

AutoCAD refers to command-first editing as verb-noun editing and to selection-first editing as noun-verb editing. When you see this terminology in the Options dialog box or the online Help system, don’t worry — you haven’t dropped back into fifth-grade English class!

Choosing an editing style

This book emphasizes command-first editing because, in its heart of hearts, AutoCAD is a command-first program. In fact, it started out offering only command-first editing and later added the selection-first methods. I stress command-first editing for these reasons:

• Longevity: It’s the oldest editing style in AutoCAD, and the one with which experienced AutoCAD users are most familiar.
• Naturalness: Would you say, “I want to eat my lunch”? or “My lunch I want to eat”? Okay, so Yoda might say, “Eat my lunch I want to!”
• Consistency: It works consistently with all editing commands — some editing commands are command-first only.
• Flexibility: It allows greater flexibility in object selection than the other methods, which is useful when you work on busy complex drawings.

After you know how to do command-first editing, you can simply reverse the order of many editing operations to perform them in selection-first style instead. But if you don’t become familiar with command-first editing in the beginning, you’ll be bewildered by the useful AutoCAD commands that work only in the command-first style; commands such as these ignore the objects you’ve already selected and prompt you to select objects before you can continue.

Much of the information in the rest of this book assumes that you’re using the AutoCAD’s default selection settings. If you find that object selection or grip-editing is working differently from the way it’s described in this chapter, click the Application button, choose Options from the bottom of the Application menu to open the Options dialog box, and then check the settings on the Selection tab. The following check box settings should be selected (as shown in Figure 10-1), and all other check box settings should be deselected:

• Noun/Verb Selection
• Object Grouping
• Implied Windowing
• Allow press and drag for Lasso
• Show Grips
• Show Grip Tips
• Show Dynamic Grip Menu
• Allow Ctrl+Cycling Behavior
• Show Single Grip on Groups
• Show Bounding Box on Groups
• Selection Preview when a Command Is Active
• Selection Preview when No Command Is Active
• Command Preview
• Property Preview

For information on what these options do, hover the mouse pointer over an option to display a tooltip with information or else visit the online Help system.

Selecting Objects

Part of AutoCAD’s editing flexibility comes from its object selection flexibility. For example, command-first editing offers 16 selection modes, whereas selection-first editing has only six. I describe the most useful ones in this chapter. Don’t worry, though: You can squeak by most of the time using only the three that I describe in this section:

• Select a single object by picking it.
• Select multiple objects by enclosing them in a window selection box, polygon, or lasso.
• Select multiple objects by enclosing them in a crossing selection box, polygon, or lasso.

Most editing commands affect the entire group of selected objects.

Selection boxes left and right

Selecting objects one at a time works well when you want to edit a small number of objects, but many CAD editing tasks involve editing lots of objects at the same time. Do you really want to pick 132 lines, arcs, and circles, one at a time? Okay, maybe you do if you’re paid by the hour, but after a while your company won’t be able to afford you.

Like most Windows graphics programs, AutoCAD provides a selection window for grabbing a bunch of objects in a rectangular area. As you may guess, the AutoCAD version of this feature is a bit more powerful than the one in other Windows graphics programs. AutoCAD calls its version implied windowing. Here’s how you use it:

• Window object selection: When you click a blank area of the drawing (not on an object), you’re telling AutoCAD that you want to specify a selection by placing a window around the objects. When you move the cursor to the right before picking the next corner of the selection area, you’re further implying that you want to select all objects that reside completely within the selection area.

  When you drag the cursor to the right (without lifting the right mouse button), you draw a selection lasso, which also selects all objects completely within the lasso.

• Crossing object selection: When you click a blank area of the drawing (not on an object), you’re indicating that you want to specify a selection by placing a window around and through the objects. If you move the cursor to the left before picking the next corner of the selection area, you’re indicating that you want to select all objects that reside completely within or touch or cross the selection area boundary.

  Dragging the cursor to the left draws a crossing selection lasso.

Fortunately, AutoCAD gives you visual cues about the difference in motion. As you move to the right, the window area appears as an area with a blue fill and a solid border. As you move to the left, the crossing area appears as an area with green fill and a dashed border.

If your editing method of preference is selection-first, AutoCAD gives you fewer selection options. But here is a selection-first trick most AutoCAD users don’t know about: As you begin to drag the mouse, notice that the command line prompts you to press the spacebar. While keeping the right mouse button pressed, tap the spacebar to switch from Crossing Lasso (the default), to Window Lasso, Fence Lasso, and then back to Crossing Lasso selection mode.

Figures 10-2 and 10-3 show a window box and a crossing box, respectively, in action. The fill colors are the same, whether in a selection box, polygon, or lasso.

Perfecting Selecting

When you type ? and press Enter at any Select objects prompt, AutoCAD lists all command-first selection options on 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.

To use any command-first selection options at the Select objects prompt, type the uppercase letters (see Table 10-1) that correspond to the option you want, and then press Enter. For example, type CP for crossing polygon mode. When you've finished selecting objects, press Enter again to tell AutoCAD that you want to start the editing operation.

After you finish selecting objects, you must press Enter to tell AutoCAD that you want to start the editing operation. Say … is there an echo in here? As a matter of fact, I am repeating myself. Many new AutoCAD users find it difficult to remember the necessity of pressing Enter after they finish selecting objects.

The selection preview features in AutoCAD remove much of the doubt over which objects you’re selecting. Rollover highlighting displays individual objects with a thick lineweight as you move the cursor over them. Area selections display transparent, colored areas when you use any window or crossing option.

The following steps show you 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:

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

   Don’t be too particular in drawing them because you blow them away in this step list.

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, operates on those objects (selection-first editing) instead of prompting you to select objects (command-first editing). For the reasons I describe in the section “Commanding and Selecting” earlier in this chapter, I recommend using the command-first 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.

3. Click the Erase button in the Modify panel on the Home tab or enter the Erase command.

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

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

   AutoCAD adds each object to the selection set. The color of the objects you select changes to light gray, and AutoCAD continues to display the Select objects prompt.

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

   Move the cursor to a point below and to the left of the objects, click, release the mouse button, move the cursor 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 lasso that completely encloses a few objects and cuts through several others.

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

   All objects that are completely within, crossing through, or touching the lasso are selected. AutoCAD continues to display the Select objects prompt.

7. Type WP and press Enter to activate the WPolygon (Window Polygon) selection option.

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

8. Pick a series of points and press Enter.

   Figure 10-4 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.

9. Press Enter to end object selection.

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

Did you notice how you can 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 mean to do away with so many objects, enter the U command or click 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 when you’ve run other commands after Erase. This approach works only with objects you erased earlier.

The Erase command isn’t the only way to remove unwanted objects from the drawing. The easiest method in any workspace is to select one or more objects, and then press the Delete key on the keyboard.

Drawing objects on top of other objects is all too easy to do, and after you’ve done so, AutoCAD recognizes when multiples exist by displaying a tiny icon of overlapping rectangles. If the Selection Cycling button is enabled on the status bar and you pick with overlapping objects, AutoCAD opens a Selection dialog box from which you choose the one object you want.

AutoCAD Groupies

AutoCAD lets you select a bunch of objects and gather them into a group so that when you click one object, everything in the group is selected. You simply select one or more objects and click Group on the Groups panel of the Home tab. If you want, you can name the group as you create it. The buttons on the main Groups panel let you create new groups, toggle group selection off and on, edit groups by adding or removing individual objects, or permanently ungroup a selected group.

The many object-selection modes that I describe in earlier sections — and some that I don’t even describe, such as the FIlter command (check out the online Help system for more on that topic) — are useful as far as they go.

Object Selection: Now You See It …

AutoCAD lets you control the visibility of individual objects, which is a big deal. Before AutoCAD 2011, the only way to change the display of objects was to turn off or freeze the layer on which they resided. If the layer held other objects that you did want to see — too bad. These three commands turn this limitation into ancient history:

• HIDEOBJECTS: Prompts you to select the objects that you want to make temporarily disappear from view
• ISOLATEobjects: Prompts you to select the objects that you want to see, while temporarily making all others disappear
• UNISOLATEobjects: Ends both the hiding and isolating of all objects

The primary method of invoking these commands is via the right-click menu. Using either command-first or selection-first editing as described in the section “Commanding and Selecting,” earlier in this chapter, simply right-click and you see the Isolate item, shown in Figure 10-5. A status bar icon — a lightbulb at the lower-right corner of the display — is dimmed when objects are either hidden or isolated. Click this icon to open a menu that lets you turn off the hiding or isolating.

If you’re worried about the possible implications of this concept (“Hmm. I was sure I added those center lines. Do I need to add them again?”), relax. Hiding and isolating objects is temporary — it lasts only as long as the current drawing session. When you close a drawing with objects isolated or hidden, they reappear when you reopen the file.

Rumor has it that the Autodesk programmers stole this cloaking-and-uncloaking concept from the Romulans.