To nail a 3 point bend use the marks scott described.
Multiply the height of the obstruction by 2.5 and use that as the measurement from the center mark.
Center bend 45 degrees each side of center 22.5 degrees
Go to this link
http://www.eescodist.com/ugly/chapter20.asp for some better description.
[This message has been edited by iwire (edited 01-03-2004).]