Chamfering Corners

If your design requires you to draw a beveled corner, use the CHAMFER command. The CHAMFER command is used to bevel corners formed by two nonparallel lines, rays, xlines, or polylines. To issue this command, you choose Chamfer from the Modify pull-down menu or toolbar. To use the CHAMFER command, you first set the parameters defining the bevel to be generated and then select the two line segments that form the corner.

Another major enhancement to the CHAMFER and FILLET commands is the ability to fillet separate polylines into one continuous polyline.

Defining the Bevel

To obtain the desired bevel, you first define one of two sets of parameters. One set of parameters, accessed with the Distances option, enables you to define the beveling operation with two distances—one along the first selected line and the other along the second selected line. Both distances are measured from the corner, or intersection, of the two lines (see Figure 10.22).

The other set of parameters, accessed with the Angle option, consists of a distance measured from the corner point along the first selected line and the angle of the new line relative to the first selected line (see Figure 10.23).

You can use either one or both the Distances and Angle options, depending on what design information is available to you. The CHAMFER command uses the most recently defined set of parameters. If both sets of parameters are defined, you can switch between them by using the Method option.

In previous versions of AutoCAD, when you selected either the Distances or the Angle option and set the parameters, the CHAMFER command ended. You then had to repeat the command and select the two line segments to produce the bevel. However, now the command will continue, allowing you to go ahead and chamfer your objects.

The two lines you bevel do not have to intersect at a corner point. CHAMFER automatically trims or extends the two selected lines to an intersecting point before generating the bevel line. A quick way to trim or extend two lines to a corner point is to use the CHAMFER command with the distances set to zero (see Figure 10.24).

If the two lines selected are on the same layer and have identical color and linetype properties, the new bevel line is drawn with the same properties. If there is a difference in a particular property of the two selected objects, the bevel line takes on the drawing’s current object property value. For example, if the two selected lines are drawn on different layers, the new bevel line is drawn on the current layer. If the two selected lines are drawn with a different color, the bevel line is drawn with the current color property. If the two selected lines are drawn with a different linetype, the bevel line is drawn with the current linetype property.

Dealing with Polylines in the CHAMFER Command

To bevel all the corners of a polyline simultaneously, specify the Polyline option and select the target polyline. Be aware, however, that when you generate a bevel line at any angle other than 45 degrees relative to the selected lines, the result will not be symmetrical (see Figure 10.25).

This asymmetric result is produced because the polyline segments are processed in the order in which they are drawn. To produce a symmetrically beveled shape, you must bevel one corner at a time. By explicitly selecting the first and second line segments, you control how much each segment is trimmed.

To Trim or Not to Trim

As previously stated, by default, CHAMFER extends or trims the lines to a corner point before applying the chamfer distances and/or angle. If, however, you want to draw the bevel line without any modifications to the original lines, choose the Trim option. At this point, you can choose between the Trim and No Trim settings. If you do not want the original lines modified, choose the No Trim setting. In the following exercise, you use the CHAMFER command to bevel the corners of a rectangle.

Exercise 10.6 Beveling the Corners with CHAMFER

1.	Open the drawing CHAMFILL.DWG on the accompanying CD. This drawing contains Plan and Elevation views of a part. Using Chamfer, you are going to bevel the corners in the Plan view.
2.	Select Chamfer from the Modify toolbar or drop-down list, then use the Angle option to set the chamfer distance to 1 and the chamfer angle to 45 degrees.
3.	Then choose the Polyline option and select the rectangle in the Plan view. Note that all the corners are beveled in one operation.
4.	Choose Undo from the Standard toolbar to undo the CHAMFER command, and the rectangle is restored to its original shape.
5.	Repeat the CHAMFER command, selecting the two lines that form the upper-left corner of the rectangle (see Figure 10.26). Then repeat the CHAMFER command again and select the two lines that form its upper-right corner. The two top corners are now beveled at a 45-degree angle. Figure 10.26. Using CHAMFER to bevel the corners of the rectangle.
6.	Repeat the CHAMFER command, but this time specify the Distances option. Set the first distance to 1.0 and the second distance to 0.5.
7.	Select the lines that form the lower-left corner with and . Then repeat the CHAMFER command and select the lines that form the lower-right corner with and . Remember that the order in which you select the lines is important. Your rectangle should resemble the one in Figure 11.26. This drawing is used in the next exercise, so keep it open.