Generating Elevations - AutoCAD 2011 and AutoCAD LT 2011: No Experience Required - page 515

trimming Lines in the Elevation
The next task is to extend and trim the appropriate lines in the elevation. You'll
start by extending the roof lines:
1. Click the Extend button in the Modify panel of the Home tab, and then
select the two outermost construction lines extending from the roofline
in plan view and press ↵ . These are the boundary edges.
2. Click once on each end of the top four horizontal lines—the ridgeline,
the top and bottom of the roof covering, and the bottom of the soffit
(see Figure 10.10).
FiGuRE 10.10 The elevation after extending the roof lines
3. Start the TRIM command; pressing ↵ when prompted to select cutting
edges. By not selecting any cutting edges, every edge in the drawing
is used as a cutting edge.
Enter F ↵ to choose the Fence option, and then draw a fence line along
the bottom of your elevation, as shown in Figure 10.11. Press ↵ ↵ to
apply the fence line and end the TRIM command.