You use vertical alignment settings to control the placement of the door in the wall, the location of the working point vertically in the wall, and how the door responds to modifications in height. To determine the working point on the door, use the threshold and head height settings. You can place the working point at the sill or at the head. For example, if you specify the vertical alignment as 0'' and the door height as 7'–0'', the door opening height is 7’–0''. If you next specify the height of the door as 6'–8'', the door threshold remains at 0'' and the door opening height becomes 6’–8''.
For the door head working point, if you specify the vertical alignment as 7'–0'' and the door height as 7'–0'', the door opening height is 7–0''. If you specify the door height as 6'–8'', the door head remains at 7'–0'' and the door threshold becomes 4''.