Selecting Objects


Like most of today's graphics programs, AutoCAD lets you select objects in a drawing in a variety of ways. Unfortunately, these methods aren't always consistent throughout AutoCAD's set of commands. In the following sections, you'll learn about the most common methods for selecting objects.

Using the Standard AutoCAD Selection Method

Many AutoCAD commands prompt you to select objects with the Select objects: prompt. Along with this prompt, the cursor changes from a crosshair cursor to a small square.

image from book

Whenever you see the Select objects: prompt and the square cursor, called the Object Selection cursor, you have a couple of options while making your selection. You can click objects individually or select groups of objects using a rectangular selection area. AutoCAD also provides options to select areas using an irregular polygon boundary.

AutoCAD's behavior when you are selecting an object is a little different from that of other graphics programs. If you see the Select objects: prompt, you are actually in a selection mode, and every action you take is inferred by AutoCAD to be a selection operation. You can continue to add or subtract selections, but AutoCAD won't know you're finished selecting objects until you press .

As already mentioned, you can click objects to select them. Each time you click an object, it is added to the selection set, which is the set of objects to be edited by the current command. You can also select objects using a window, commonly called a marquee in other programs. To remove a selection, Shift+click the object. This is the reverse in most other graphics programs, which require a Shift+click to add objects to a selection.

Practicing Using Selection Options

In this section, you'll learn about the most common selection options in AutoCAD and see what to do when you make the wrong selection.

Before you continue, you'll turn off running osnaps and osnap tracking. Although extremely useful, these features can be confusing to new users.

  1. Look at the Osnap and Otrack buttons in the status bar at the bottom of the AutoCAD window. If they are turned on, they look like they are pressed down. Click them to turn them off.

    image from book

  2. You'll want to draw something so you can practice on it. Click the Line tool in the 2D Draw control panel, and then draw the four sides of a rectangle roughly like the one shown in Figure 4.1. Remember that you can draw the first three sides and then enter C to "close" the rectangle.

  3. image from book Click the Arc tool in the 2D Draw control panel, and select three points to draw an arc roughly where one appears in Figure 4.1. The arc does not have to be exact, but you should place it above the rectangle.

image from book
Figure 4.1: A rectangle, drawn using the Line tool, and an arc

Now you'll see how to select an object in AutoCAD. In the following exercise, you'll practice using a single click to select objects one at a time:

  1. Place the cursor over any object, but do not click just yet. As the cursor hovers over an object, notice that the object highlights. This shows you the object AutoCAD will select if you click, and it shows you the extent and shape of the object you are about to select.

  2. Click each of the two horizontal lines of the rectangle. As you select an object, it is highlighted, as shown in Figure 4.2.

    Once you've made a selection, you can deselect objects that you selected accidentally.

  3. Hold down the Shift key, and click one of the highlighted lines. It reverts to a solid line, showing you that it is no longer selected for editing.

  4. Shift+click the remaining selected line. Now you're back to having nothing selected.

image from book
Figure 4.2: Selecting the lines of the rectangle and seeing them highlighted

Clicking objects is perhaps the most intuitive and easiest way to select objects. The additional highlighting helps you determine whether you are about to select the right object.

Clicking works fine when you need to be precise about selecting individual objects, but you'll also need a way to select multiple objects efficiently. Next you'll look at the selection window, which lets you quickly select groups of objects.

Selecting Objects with Windows

When you click a blank portion of the drawing area, AutoCAD automatically starts a selection window. A selection window lets you enclose a set of objects to select them. The following exercise demonstrates how it works:

  1. Select a point above and to the left of the rectangle shown in the left image of Figure 4.3. Be sure not to select the rectangle itself. Now a window appears that you can drag across the screen as you move the cursor. If you move the cursor to the left, the window appears dotted (see the left image in Figure 4.3) and has a green tint. If you move the cursor to the right, it appears solid with a blue tint (see the right image in Figure 4.3).

  2. Select a point below and to the right of the rectangle so that the rectangle is completely enclosed by the window, as shown in the right image in Figure 4.3. The rectangle is highlighted. Notice that the arc is not selected, even though you might have partially included it in the window.

  3. Press Esc to clear the entire selection at once.

image from book
Figure 4.3: The dotted window (left image) indicates a crossing selection; the solid window (right image) indicates a standard selection window.

The two windows you have just seen, the solid, blue tinted one and the dotted, green one represent a standard window and a crossing window. If you use a standard window, anything that is completely contained within the window is selected. If you use a crossing window, anything that is contained within or crosses through the window is selected. These two types of windows start automatically when you click any blank portion of the drawing area with either the standard cursor or the Point Selection cursor.

Next, you will select objects with an automatic crossing window:

  1. Select a point below and to the right of the rectangle, as shown in Figure 4.4. As you move the cursor left, the crossing (dotted) window appears, and the window area is tinted green if you are using a white background.

  2. Place the window so it encloses the rectangle and part of the arc (see Figure 4.4), and then click to confirm your selection area. Both the rectangle and arc are highlighted.

image from book
Figure 4.4: The rectangle enclosed by a crossing window

Using the selection window and clicking is all you need to do to select objects in AutoCAD. Often you can select a group of objects with either the standard window or the crossing window and then Shift+click to remove anything from the selection set that you don't want to include in the selection. If you are working in a crowded drawing, you can use the scroll wheel of your mouse to zoom in and out while you are selecting objects. It also helps to turn off the Snap mode while making your selections.




Introducing AutoCAD 2008
Introducing AutoCAD 2008
ISBN: 0470121505
EAN: 2147483647
Year: 2007
Pages: 147
Authors: George Omura

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