trying to place a continuous footing with a conc. wall on top. I have created a wall type for the footing 16" wide x 8" tall. In the Wall Pref's, Insertion options I find options for height, top bound (then a plethora of options) Top offset, bottom bound (another plethora of options) and bottom offset. What is the relation of top bound to top offset, and bottom bound to bottom offset? and why can't it just be "z" ? I want the bottom of the footing at -40.25" . The layer elevation is to to of foundation which is -10.25". Foundation wall is 24" .
I realize all the options are there to construct some complicated walls. This is a simple and common situation can someone dummy it down for me?