AutoCAD 2005 For Dummies (2004)
.pdf
140 Part II: Let There Be Lines
Displacement vector
Original location |
Drag image to new location |
Figure 6-4:
Dragging objects in the middle of the MOVE command.
Specify a base point somewhere on or near the object(s) that you’re moving. You can use an object snap mode to choose a point exactly on one of the objects.
AutoCAD displays the following prompt:
Specify second point of displacement or <use first point
as displacement>:
6. Specify the second point by clicking a point or typing coordinates.
The second point serves as the arrow end of your imaginary displacement arrow. After you specify the second point, AutoCAD moves the objects.
Don’t press Enter alone at this prompt! If you do, AutoCAD treats the X,Y coordinates of the first point you picked as an absolute displacement, and the objects fly off in an unpredictable fashion.
Chapter 6: Edit for Credit 141
These are common precision techniques for specifying the second point:
Use an object snap mode to pick a second point exactly on another object in the drawing.
Type a relative or polar coordinate, as described in Chapter 4. For example, if you type @6,2, AutoCAD moves the objects 6 units to the right and 2 units up. If you type @3<45, AutoCAD moves the objects 3 units at an angle of 45 degrees.
Use direct distance entry to move objects in an orthogonal or polar tracking direction. See Chapter 4 for instructions.
Copy
The CoPy command works almost identically to the Move command, except that AutoCAD leaves the selected objects in place and moves new copies of them to the new location. The CoPy command also includes a Multiple option for making multiple copies of the same set of objects. You activate the Multiple option by typing M and pressing Enter after you finish object selection. As always, you must watch the command line prompts to find out what you can do and when to do it!
Copy between drawings
You can’t copy objects from one drawing to another with the CoPy command. Instead, you use the COPYCLIP command, together with its companion command, PASTECLIP. Follow these steps:
1. Open two drawings that contain geometry you want to copy from one to the other. Arrange the two drawings so that you can see both of them, as shown in Figure 6-5.
If you don’t have enough screen real estate to arrange the two drawings side by side, you can leave them overlapped and change between the two drawing windows by using the Window menu or by pressing Ctrl+Tab.
2.In the first drawing, right-click in the drawing area and choose Copy from the cursor menu.
Choose Cut if you want to move rather than copy the objects to the other drawing. Choose Copy with Base Point if you want to choose a specific base point rather than let AutoCAD choose a base point.
The base point that AutoCAD chooses is the lower-left corner of an imaginary rectangle that just barely encloses all the objects you’ve selected.
3.If you chose Copy with Base Point in Step 2, pick a base point to use for the copy operation.
The base point is like a base point for a block definition, as described in Chapter 13. Choose a useful point such as the endpoint of a line, the lower-left corner of a rectangle, or the center of a circle.
142 Part II: Let There Be Lines
Figure 6-5:
Copying objects between drawings.
4.Select the objects that you want to copy and then press Enter to end object selection.
5.Click in the second drawing’s window to make it current.
6.Right-click in the second drawing’s window and choose Paste from the cursor menu.
Choose Paste to Original Coordinates if you want to copy the objects so that they land at the same point (with respect to 0,0) in the second drawing as they were located in the first drawing.
7.Specify an insertion point for the copied objects by object snapping to a point on an existing object or typing absolute X,Y coordinates.
AutoCAD copies the objects.
It’s easy to confuse the CoPy and COPYCLIP commands:
CoPy is AutoCAD’s primary command for copying objects within a drawing.
COPYCLIP — along with related commands like CUTCLIP and PASTECLIP — is AutoCAD’s version of copy and paste via the Windows Clipboard.
Chapter 6: Edit for Credit 143
(You can use the Windows Clipboard cut-and-paste method to copy or move objects within a single drawing, but using the AutoCAD CoPy and Move commands usually gives you better control and precision.)
Table 6-2 summarizes AutoCAD’s Clipboard-related commands, along with the equivalent choices on the right-click menu and the Standard toolbar.
Table 6-2 |
AutoCAD Clipboard Commands |
|
Cursor Menu Choice |
Command Name |
Toolbar Button Name |
Cut |
CUTCLIP |
Cut to Clipboard (Ctrl+X) |
|
|
|
Copy |
COPYCLIP |
Copy to Clipboard (Ctrl+C) |
|
|
|
Copy with Base Point |
COPYBASE |
none |
|
|
|
Paste |
PASTECLIP |
Paste from Clipboard (Ctrl+V) |
|
|
|
Paste as Block |
PASTEBLOCK |
none |
|
|
|
Paste to Original Coordinates |
PASTEORIG |
none |
|
|
|
Stretch
The Stretch command is superficially similar to CoPy and Move; it has the same inscrutable base point and displacement prompts, and it shifts objects — or parts of objects — to other locations in the drawing. But it also has important differences that often confound new AutoCAD users to the point where they give up trying to find out how to use Stretch. That’s a mistake, because Stretch is a valuable command. With it, you can perform editing operations in seconds that would take many minutes with other commands. Here are the things you need to know to make Stretch your friend:
To use Stretch, you must select objects by using a crossing selection box (or crossing polygon), as described in the section “Perfecting Selecting,” earlier in this chapter. See Figure 6-6.
Stretch operates on the defining points of objects — endpoints of a line, vertices of a polyline, the center of a circle, and so on — according to the following rule: If a defining point is within the crossing selection box that you specify, AutoCAD moves the defining point and updates the object accordingly.
For example, if your crossing selection box surrounds one endpoint of a line but not the other endpoint, Stretch moves the first endpoint and redraws the line in the new position dictated by the first endpoint’s new location. It’s as though you have a rubber band tacked to the wall with two pins, and you move one of the pins. See Figure 6-7.
144 Part II: Let There Be Lines
Figure 6-6:
Use a crossing selection box to select objects for stretching.
Figure 6-7:
Stretch moves defining points that lie within the crossing selection box.
Stretch can make lines longer or shorter, depending on your crossing selection box and displacement vector. In other words, the Stretch command really combines stretching and compressing.
You usually want to turn on ortho or polar tracking mode before stretching. Otherwise, you’ll end up stretching objects in strange directions, as shown in Figure 6-8.
Figure 6-8:
The hazards of stretching without ortho or polar tracking turned on.
Chapter 6: Edit for Credit 145
The following steps describe how to Stretch lines:
1.Draw some lines in an arrangement similar to the dark lines shown in Figure 6-9.
Start your stretching with simple objects. You can work up to more complicated objects — polylines, circles, arcs, and so on — after you’ve limbered up with lines.
2.Press Esc to make sure that no command is active and no objects are selected.
3.Click the Stretch button on the Modify toolbar.
The command line displays the Select objects prompt, with a warning to use the Crossing or CPolygon object selection mode:
Select objects to stretch by crossing-window or crossingpolygon...
Select objects:
4.Specify a crossing selection box that encloses some, but not all, endpoints of the lines.
Figure 6-9 shows a sample crossing selection box that completely encloses the two vertical lines on the right side of the figure. This crossing selection box cuts through the four horizontal lines, enclosing only one endpoint of each.
You specify a crossing selection box by picking a point, moving your mouse to the left, and picking a second point.
5.Press Enter to end object selection.
AutoCAD displays the following prompt.
Specify base point or displacement:
6.Specify a base point by object snapping to a point on an existing object or by typing absolute X,Y coordinates.
This step is just like Step 5 in the Move procedure earlier in this chapter.
AutoCAD displays the following prompt.
Specify second point of displacement or <use first point
as displacement>:
7.Toggle ortho mode on and then off by clicking the ORTHO button on the status bar; try moving the cursor around first with ortho mode on and then with it off to see the difference.
Figure 6-9 shows what the screen looks like as you move the cursor around with ortho off.
146 Part II: Let There Be Lines
|
Crossing window pick point 1 |
Original location |
Displacement vector |
Figure 6-9:
Dragging objects in the middle of the Stretch command.
Crossing window pick point 2 Drag image to new location
8.Toggle ortho mode on and then specify the second point — usually by using direct distance entry, object snapping to a point on an existing object, or typing relative X,Y coordinates.
This step is just like Step 6 in the Move procedure earlier in this chapter. After you pick the second point, AutoCAD stretches the objects. Notice that the Stretch command moved the two vertical lines because the crossing selection box contained both endpoints of both lines. Stretch lengthened or shortened the four horizontal lines because the crossing selection box enclosed only one endpoint of each.
The Stretch command takes some practice, but it’s worth the effort. Draw some additional kinds of objects and practice stretching with different crossing selection box locations as well as different base points and second points.
Chapter 6: Edit for Credit 147
More manipulations
The commands in this section — ROtate, SCale, ARray, and OFfset — provide other ways (in addition to Move, CoPy, and Stretch) of manipulating objects or creating new versions of them. The procedures for each command assume that you’re familiar with the object selection and editing precision techniques presented in the Move, CoPy, and Stretch procedures (see the previous sections in this chapter).
Rotate
The ROtate command “swings” one or more objects around a point that you specify. Follow these steps to use the ROtate command:
1.Press Esc to make sure that no command is active and no objects are selected.
2.Click the Rotate button on the Modify toolbar.
3.Select one or more objects and then press Enter to end object selection.
AutoCAD prompts you for the base point for rotating the selected objects:
Specify base point:
4.Specify a base point by clicking a point or typing coordinates.
The base point becomes the point about which AutoCAD rotates the objects. You also have to specify a rotation angle:
Specify rotation angle or [Reference]:
5.Specify a rotation angle by typing an angle measurement and pressing Enter.
Alternatively, you can indicate an angle on the screen by moving the cursor until the Coordinates section of the status bar indicates the desired angle and then clicking. If you choose this alternative, you will need to use ortho mode or polar tracking to indicate a precise angle (for example, 90 or 45 degrees) or an object snap to rotate an object so that it aligns precisely with other objects.
After you specify the rotation angle by typing or picking, AutoCAD rotates the objects into their new position.
148 Part II: Let There Be Lines
Scale
If you read all my harping on drawing scales and drawing scale factors in Chapter 3, you may think that the SCale command performs some magical scale transformation on your entire drawing. No such luck. It merely scales one or more objects up or down by a factor that you specify. Here’s how it works:
1.Press Esc to make sure that no command is active and no objects are selected.
2.Click the Scale button on the Modify toolbar.
3.Select one or more objects and then press Enter to end object selection.
AutoCAD prompts you for the base point about which it will scale all the selected objects:
Specify base point:
AutoCAD does not scale each object individually around its own base point (because most AutoCAD drawing objects don’t have individual base points). Instead, AutoCAD uses the base point that you specify to determine how to scale all objects in the selection set. For example, if you select a circle to scale, pick a point outside the circle as the base point, and then specify a scale factor of 2, AutoCAD not only makes the circle twice as big, but also moves the circle twice as far away from the base point that you specified.
4. Specify a base point by picking a point or typing coordinates.
The base point becomes the point about which the objects are scaled.
AutoCAD prompts you for the scale factor:
Specify scale factor or [Reference]:
5.Type a scale factor and press Enter.
AutoCAD then scales the objects by the factor that you type, using the base point that you specified. Numbers greater than one increase the objects’ size. Numbers smaller than one decrease the objects’ size.
Changing the drawing scale factor of a drawing after you’ve drawn it is a tedious and complicated process in AutoCAD. In brief, you need to change the scale-dependent system variables described in Chapter 3, and then scale some, but not all, drawing objects. You don’t scale the real-world geometry that you’ve drawn, because its measurements in the real world remain the same. You do scale objects such as text and hatching that have a fixed height or spacing regardless of drawing scale factor. (The SCALETEXT command can help with this operation. See Chapter 9 for more information.) Because of these complications, try to make sure that you choose a proper scale and set up the drawing properly for that scale before you begin drawing. See Chapter 3 for details.
Chapter 6: Edit for Credit 149
Array
The ARray command is like a supercharged CoPy: You use it to create a rectangular grid of objects at regular X and Y spacings or a polar wheel of objects at a regular angular spacing. For example, you can use rectangular arrays to populate an auditorium with chairs or a polar array to draw bicycle spokes.
The following steps describe how to create a rectangular array, which you’ll probably do more often than creating a polar array:
1.Press Esc to make sure that no command is active and no objects are selected.
Alternatively, you can select objects before starting the ARray command and thereby skip Step 3.
2.Click the Array button on the Modify toolbar.
The Array dialog box appears, as shown in Figure 6-10.
Figure 6-10:
ARray makes duplicates of objects in a rectangular or polar pattern.
3.Click the Select Objects button, and then select one or more objects. Press Enter to end object selection and return to the Array dialog box.
4.Make sure that the Rectangular Array radio button is selected.
If rectangular arrays seem too square, choose the cool Polar Array radio button instead and experiment with the other array option.
5.Fill in the five edit boxes: Rows, Columns, Row Offset, Column Offset, and Angle of Array.