The default geometry of the roofs as they first appear when Roof Input view is invoked is entered here.
Default inputs for roof construction (flat, hip or gable), roof slope, and length of overhang apply to each new roof block created in Plan View.
Note that these settings should be set early on in the process, preferably before a file is created. Once a block is drawn, its roof settings are fixed at this point, even though the roof is not visible until you get to Roof action.