Generating Elevations - AutoCAD 2011 and AutoCAD LT 2011: No Experience Required - page 520

t I p s F o r U s I n g t h e TRIM a n d EXTEND C o M M a n d s (Continued)

trimming and Extending in the Same Command
If you find that a cutting edge for trimming can also serve as a boundary
edge for extending, hold down the Shift key and click a line to extend it to
the cutting edge. The opposite is true for the EXTEND command.

Correcting Errors
It's easy to make a mistake in selecting cutting or boundary edges or in
trimming and extending. You can correct a mistake in two ways:
If you select the wrong cutting or boundary edge, enter

R ↵ and then
choose the lines again that were picked in error. They will lose their
highlighting. If you need to keep selecting cutting or boundary edges,
enter A ↵ and select new lines. When finished, press ↵ to move to the
second part of the command.
If you trim or extend a line incorrectly, enter

U ↵ or right-click and
choose Undo from the context menu. This undoes the last trim. Click
Undo again if you need to untrim or unextend more lines. When you
have made all the corrections, continue trimming or extending. Press
↵ to end the command.
If the command ended and you click the Undo button, you will undo all
trimming or extending that was done in the preceding command.

Assigning Elevation Layers

You set the A-ELEV-WALL layer current as you began drawing your elevation view.
At that point you were mostly interested in getting the elevation's geometry in
place, and not as much about layers. With that now in place, now is a good time to
pause for a moment and place everything on the correct layers. Currently, the exte-
rior walls, roof, and windows are drawn. Follow these steps to assign the A-ELEV-
WALL, A-ELEV-ROOF, and A-ELEV-GLAZ respectively to those objects:

1. Select the lines shown in Figure 10.16, and use the layer pull-down
found on the Layers panel of the Home tab to assign the A-ELEV-
ROOF layer.