Scaling, Stretching, and Rotating

You can scale, stretch, and rotate as well as move and copy objects with grips. But as described for the Move and Copy commands, you can also use specific commands for each of these operations. Like the Move and Copy commands, the Scale, Stretch, and Rotate commands give you more flexibility in your selection of objects.

Scaling to a Specific Scale Factor

To use the Scale command to change the size of an object or a set of objects, do the following:

1. From the 2D Draw control panel's Modify fly-out toolbar, choose Scale, choose Modify è Scale, or enter sc↲ at the command prompt.

2. At the Select objects: prompt, select the objects you want to scale, and press ↲.

3. At the Specify base point: prompt, select a point around which to scale. If you select a corner of a rectangle, for example, the corner remains in place while the rest of the rectangle expands or contracts around the corner.

4. At the Specify scale factor or [Copy/Reference]: prompt, enter a scale value. The selected objects change to the specified scale.

Scaling an Object to Fit Another

A useful feature of the Scale command is the Reference option, which lets you scale an object to match the size of another. The following example shows how to use the Reference option to change the size of a door in a floor plan to fit an enlarged opening:

1. From the 2D Draw control panel, choose Scale, choose Modify è Scale, or enter sc↲ at the command prompt.

2. At the Select objects: prompt, select an object or objects.

3. At the Specify base point: prompt, use the Endpoint osnap to select the corner of the door, as shown in the left image in Figure 5.20.

4. At the Specify scale factor or [Copy/Reference]: prompt, enter r↲.

5. At the Specify reference length <1>: prompt, use the Endpoint osnap, and select the same corner of the door you selected in step 3. You can also enter @↲ since the last point you selected was the point you selected in step 3.

6. At the Specify second point: prompt, select the endpoint of the arc that represents the door swing, as shown in the middle image in Figure 5.20.

7. At the Specify new length or [Points]: prompt, notice that the door swing endpoint follows the cursor while the corner of the door stays fixed in its corner location. Use the Endpoint osnap again, and select the other corner of the door opening, as shown in the right image in Figure 5.20.

Figure 5.20: Scaling a door to fit an opening

In this example, a door is scaled to fit an opening. This door already had one corner at the same location as one side of the opening. To scale an object to fit another, you need to first align the location you will use as a base point to one end of the object or area to which you want to scale.

Stretching Objects

To move the endpoint of a line or a vertex of a polyline, you can use the Stretch command. Stretch lets you select a single vertex or several vertices and move them to reshape a drawing.

The basic method for using Stretch is as follows:

1. In the 2D Draw control panel's Modify fly-out menu, click the Stretch tool, choose Modify è Stretch, or enter s↲ at the command prompt.

2. At the Select objects: prompt, enter c↲. This invokes the crossing selection window.

3. Enclose the vertices you want to stretch with the crossing selection window, as shown in the left image in Figure 5.21, and then press ↲. You cannot use a standard window for this operation.

4. At the Specify base point or [Displacement] <Displacement>: prompt, select a base point.

5. At the Specify second point or <use first point as displacement>: prompt, you'll see the vertices move as you move the cursor. Select a new location for the vertices, or enter a coordinate.

Figure 5.21: Use a crossing window to select the vertices you want to stretch (left image), and then select a base point. The vertices will move with the cursor (right image).

Although the Stretch command is useful, the grip-editing version of Stretch is just as capable and a bit easier to understand.

See the section "Moving and Copying" earlier in this chapter for tips on selecting base points and objects.

Rotating Objects

In Chapter 4, you learned that you can rotate objects using grips, but in addition you can use the Rotate command to do so. To rotate an object with the Rotate command, do the following:

1. In the 2D Draw control panel, click the Rotate tool, choose Modify è Rotate, or enter ro↲ at the command prompt. You'll see the following message:

    Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0 

2. At the Select objects: prompt, select the object or objects you want to rotate, and then press ↲.

3. At the Specify base point: prompt, select a point around which objects are to be rotated. The objects rotate about the selected point as you move your cursor.

4. At the Specify rotation angle or [Copy/Reference]: prompt, enter a rotation angle value, or use the cursor to select a rotation angle.

The message you see in step 1 lets you know the current settings for the angle direction and base angle. This helps you decide whether to enter a positive or negative value for rotation angles.

Aligning the Rotation Cursor with an Object

In step 3 of the previous example, the selected objects and the cursor rotate around the selected base point. Frequently, the angle indicated by the cursor and the angle of the objects you are rotating do not coincide. This can be a problem, particularly if you want to graphically rotate the selected objects. You can align the cursor with the objects you are rotating using the Reference option. This can be helpful if you are trying to rotate one edge of an object to a specific angle or to another object. The following steps describe how you can use the Reference option to align a randomly placed rectangle with the cursor to rotate the rectangle to a specific angle:

1. Start the Rotate command, and select the objects you want to rotate.

2. At the Specify base point: prompt, select a point around which the objects are to be rotated. In the example in Figure 5.22, the cross with the circle represents the base point. Once you select a base point, the objects rotate around the selected point as you move your cursor.

3. At the Specify rotation angle or [Copy/Reference]: prompt, enter r↲.

4. At the Specify the reference angle <0>: prompt, use the Endpoint osnap to select the endpoint of the line you want aligned with the cursor, as shown in the left image of Figure 5.22.

5. At the Specify second point: prompt, select the other end of the line you want to align with the cursor, as shown in the middle image of Figure 5.22.

6. At the Specify the new angle or [Points]: prompt, notice that the object is now aligned with the cursor as it rotates about the base point. You can enter an angle value or select a point to finish the command.

Figure 5.22: Using the Reference option to align the selected objects to the cursor

You can also use the Reference option to select a specific point on an object as the location being rotated. For example, suppose you want to rotate a set of circles inside a hexagon to align with the corner of the hexagon, as shown in Figure 5.23.

Figure 5.23: The goal is to rotate the circles inside the hexagon (left view) to align with the corners of the hexagon (right view).

To do this, you can use the Reference option as follows:

1. Start the Rotate command, and select the objects you want to rotate.

2. At the Specify base point: prompt, use the Center osnap to select the center of the hexagon as represented by the central circle (see the left image in Figure 5.24). Once you do this, the objects rotate around the selected point as you move your cursor.

3. At the Specify rotation angle or [Copy/Reference]: prompt, enter r↲.

4. At the Specify the reference angle <0>: prompt, use the Center osnap to select the center of the hexagon again. You can also enter @↲ since the last point you selected was the center.

5. At the Specify second point: prompt, use the Center osnap to select the center of one of the circles you are rotating, as shown in the center image of Figure 5.24. Now as you move the cursor, the circle whose center you selected is aligned with the cursor angle.

6. At the Specify the new angle or [Points]: prompt, use the Endpoint osnap to select one of the corners of the hexagon, as shown in the right image in Figure 5.24. The circles align with the corners.

Figure 5.24: Rotating the circles to align with the corners of the hexagon

To rotate an object around a point that is some distance from your current view, draw a temporary circle whose center is at the location of the rotation center and whose radius intersects with the object you want to rotate. You can then zoom into the object you want to rotate and use the Center osnap to locate the center of the circle as the rotation base point. Delete the circle when you are done, or keep it for future edits. Consider creating a nonprinting layer on which you can keep construction objects such as the circle.