Moving and Copying

Chapter 4 described how to use grips to move and copy objects. So why have specific commands for moving and copying when you can use grips? Part of the reason is that grip editing is a feature that was added later in AutoCAD's history, and the Move and Copy commands are the original methods for performing those functions. If you are building macros, you can use the Move and Copy commands but not the grip-editing options. Finally, the Move and Copy commands described in this chapter, along with Rotate, Stretch, and Scale, can take advantage of the selection options described earlier in this chapter. Grip editing cannot. If you have to move or copy a set of objects that cannot be selected easily with single clicks or selection windows, use the Move or Copy commands in the 2D Draw control panel or Modify menu.

Moving with Accuracy

The Move command is deceptively simple. It's easy enough to move objects in a general way. It gets a little more complicated when you want to move objects with any accuracy. Here are the basic steps for using the Move command:

1. In the 2D Draw control panel, click the Move tool, choose Modify è Move, or enter m↲ at the command prompt.

2. At the Select objects: prompt, select the objects you want to move.

3. At the Specify base point or [Displacement] <Displacement>: prompt, select a base point. If you want to enter a relative coordinate, you can select any point on the screen, or you can enter @↲. The @ means "from the last point selected."

4. At the Specify second point or <use first point as displacement>: prompt, you'll see the selected objects move with the cursor. You can select the second point with the cursor or enter an absolute or relative coordinate. (See Chapter 2 for more about coordinates in AutoCAD.)

Using Some Tips for New Users

The trickiest part of the Move command is understanding the base point and the second point in steps 3 and 4 in the previous exercise. The base point can be anywhere on the drawing. It does not have to be on the object or objects you are trying to move. Once you select a base point, its position stays fixed in relation to the selected objects. This is most obvious when you select a random point for a base point. As you move the cursor, the selected objects move in unison with the cursor, even if the cursor is nowhere near the objects.

Another function that can trip up a new user is the selection process. It is a good idea to become intimately familiar with the many ways you can select objects in AutoCAD. Study the section "Selecting Objects" earlier in this chapter.

Aligning Objects with Osnaps

Finally, you can use osnaps to accurately place the objects you are moving. For example, if you want to move an object so that its corner meets the corner of a second object, do the following. Start the Move command as in step 1 of the previous exercise; select your object as in step 2; then in step 3, use the Endpoint osnap to select the corner of the selected object. In step 4, use the Endpoint osnap again to select the corner of the second object. (See the middle image in Figure 5.15.) This is just one example of using osnaps with the Move command. You can use osnaps to join any part of one object to any part of another. For example, you can move the midpoint of a line to the center of a circle using osnaps in steps 3 and 4.

Figure 5.15: Use the Endpoint osnap to select the corner of the object you want to move (left image), and then use it again to select the corner you want to move the object to (center image).

Copying Objects with the Copy Command

The Copy command is virtually identical to the Move command with the obvious difference that Copy makes copies instead of moving objects. Another difference is that you can place multiple copies in the drawing by repeatedly clicking locations or entering coordinates.

To practice using the Copy command, follow the steps shown in the previous section. The main difference is that after step 4, AutoCAD continues to prompt you with Specify second point or <use first point as displacement>:. You can then continue to make copies by clicking your drawing, or you can press ↲ to exit the Copy command. After the first copy is made, the prompt changes to Specify second point or [Exit/Undo] <Exit>.

To make parallel copies of objects, use the Offset command, as described in Chapter 3.

Making Circular Copies

To make copies in a circular pattern, you use the Array dialog box. You can create patterns such as the tick marks on a clock or the teeth in a gear. You can also set up your circular copies to remain in a fixed orientation, like the numbers on a clock.

Here are the basic steps for using the Array dialog box:

1. In the 2D Draw control panel, click Array or enter ar↲ to open the Array dialog box (see Figure 5.16).

   PROVIDING BASE POINTS

   When you use the Move or Copy command, AutoCAD prompts you for a base point, which can be a difficult concept to grasp. You must tell AutoCAD specifically from where and to where the move occurs. The base point is the exact location from which you determine the distance and direction of the move. Once the base point is determined, you can tell AutoCAD where to move the object in relation to that point.

   The base point can come in handy when you want to move or copy an object using a geometric feature of the object. For example, if you want to move the upper-right corner of a rectangle so that it connects exactly to the endpoint of a line, select the exact corner of the rectangle as the base point for the move. The following steps describe how to do this:

   1. Start the Move command, select the rectangle, and press ↲.

   2. At the Specify base point or [Displacement] <Displacement>: prompt, Shift+right-click, and select the Endpoint osnap from the shortcut menu.

   3. Click the corner of the rectangle you want to connect to the line.

   4. At the Specify second point or <use first point as displacement>: prompt, Shift+right-click again, and select Endpoint.

   5. Click the endpoint of the line. The corner of the rectangle moves to meet the endpoint of the line.

2. Click the Select Objects button. The dialog box temporarily closes, allowing you to select objects.

3. Select the objects you want to copy, and then press ↲. The Array dialog box reopens.

4. Click the Polar Array radio button at the top of the dialog box to tell AutoCAD you want a circular array. The Array dialog box displays the polar array options, as shown in Figure 5.17.

5. Click the Pick Center Point button (see Figure 5.17). The Array dialog box temporarily closes to allow you to select a center point about which the copies will be made.

6. Select the point that represents the center of the circular array. If you have an object representing the center of the array, you can use an osnap to select the object. Once you've indicated a point, the Array dialog box reopens.

Figure 5.16: The Array dialog box

Figure 5.17: The Polar Array dialog box

At this point, you've selected an object to array and you've indicated the center location of the array. If you've selected the wrong object or the wrong center point, you can go back and specify these options again.

Now, to complete the process, tell AutoCAD the number of copies in the array and the extent of the array through the circle:

1. In the Array dialog box, enter the number of copies you want in the Total Number of Items text box. The number you enter should include the original object.

2. In the Angle to Fill text box, enter the angle in degrees that you want your circular copies to fill. For example, if you enter 360, AutoCAD spreads the copies evenly over the full 360° of the circle. If you enter 180, the array fills half a circle. You can also click the Pick Angle to Fill button to the right of the Angle to Fill box to graphically select an angle in the drawing.

3. If you want the object to rotate about the array center, turn on the Rotate Items as Copied check box in the lower-left corner of the dialog box. If you turn this option off, the copies are all oriented in the same direction as the original object.

4. Click the Preview button to display the results of your array settings, plus a dialog box that offers Accept, Modify, and Cancel options.

5. Click Accept if you are satisfied with the array and the circular array appears in the drawing.

6. Or click Modify if you need to make further adjustments. When you are finished, click OK in the Array dialog box. The circular array appears in the drawing.

Copying Rows and Columns

You can use the Array dialog box to copy rows and columns. Here are the steps:

1. In the 2D Draw control panel, click the Array tool or enter ar↲ to open the Array dialog box.

2. Click the Select Objects tool to temporarily close the Array dialog box.

3. Select the objects you want to copy, and then press ↲ to confirm your selection.

4. In the Array dialog box, click the Rectangular Array radio button.

5. Change the value in the Rows text box to the number of rows you want.

6. Change the value in the Columns text box to the number of columns you want.

7. To set the distance between rows, enter a distance in the Row Offset text box.

8. To set the distance between columns, enter a distance in the Column Offset text box (see Figure 5.18).

9. When you are satisfied with the Array settings, click OK.

Figure 5.18: Copying rows and columns

AutoCAD usually draws a rectangular array from bottom to top and from left to right. You can reverse the direction of the array by entering negative values for the distance between columns and rows in steps 7 and 8.

At times, you might want a rectangular array at an angle. To accomplish this, enter the angle in the Angle of Array input box. You can also select the angle graphically by clicking the Pick Angle of Array button just to the right of the Angle of Array input box.

If you prefer, you can graphically indicate an array cell using the options in the Offset Distance and Direction section of the Array dialog box (see the bottom image in Figure 5.19). An array cell is a rectangle defining the distance between rows and columns (see the top image in Figure 5.19). You might want to use this option when objects are available to use as references from which to determine column and row distances. For example, you might have drawn a crosshatch pattern, as on a calendar, within which you want to array an object. You use the intersections of the hatch lines as references to define the array cell, which is one square in the hatch pattern.

Figure 5.19: An array cell and the Array dialog box options that let you graphically indicate array cells

You can also indicate row or column distances individually using the Pick Row Offset or Pick Column Offset buttons to the right of the Pick Both Offsets button.