roof design is simple. If you already have the perimeter walls select the roof button from the perimeter, impose the offset which is nothing but the gronda protrusion and with the tool select lines (the green segment) create your line of gronda that must be closed and without overlap. help with the editing tools (line extensions, etc....) to adjust the lines (avoid to do so with the grip). e.g. prizes to exit the perimeter creation and select the lines of grondas that need to define the slope, put the tilt on "defines inclination" in the top bar and express the slope in degrees.). When you're finished press the big green top and if you've done everything right you create the roof. revit calculates displuvi, colmi etc... remaining all that was said before: without a course and some manuals will have the most complicated life of what it takes.
Bye.
I know that already.the problem arises when there is to build a roof as I posted in the image.it is not enough to make the roof by perimeter setting the ledge
