Generating Elevations - AutoCAD 2011 and AutoCAD LT 2011: No Experience Required - page 524

7. Trim all the deck horizontal lines to the right post line, and then trim
the top four deck lines again, this time to the left post line.
Trim the vertical post lines back to the soffit line on top and the third
horizontal deck line below.
Next, draw a short vertical line from the bottom of the right post
line to the lowest horizontal line, as shown in Figure 10.21.
Select these
lines
FiGuRE 10.20 Select the cutting edges for the TRIM command.
Trim these lines
Trim these lines
To here
FiGuRE 10.21 The deck and post lines after trimming them back to their
proper lengths