Leland Leahy sends the following AutoCAD macro that will offset objects in inches — even when you are working in feet as your unit setting.
"This is useful for civil engineers who work with feet as a unit."
(defun C:OI(/ sz ofs)(setvar "cmdecho" 0)(setq sz (getreal"
What is the offset in inches: ") ofs (/ sz 12.0))(setvar "OFFSETDIST" ofs)(command ".offset" "") (prin1))
Notes from Cadalyst Tip Patrol: This macro works just as promised. To use it, save the code (all one line) as a LISP routine, load it, and then type OI on the Command line. A prompt will ask you to enter the offset distance in inches. This routine assumes you are working in feet, so one unit in AutoCAD would be equal to 1 foot. In fact, you could enter all your offsets in inches, even if the distance is 3 feet. Just type in 36 for three feet and it will still work properly. To further simplify the process, you can enter your distance as the number of inches followed by /12. For example, if you need to offset by 3 inches, enter an offset distance of 3/12. AutoCAD will do the math for you and offset your object by 0.25 feet.