A ridgeline marks the apex of each of the three roof sections on this roof plan.
Drawing a floor or a roof on a different plane.
Paring these roof types with the appropriate architectural style is recommended for a home to obtain design harmony and curb appeal.
Keep it simple stupid.
For each offset angle or change in plate.
This means that you have an imaginary plane cutting through the building at an elevation of 4 feet above the floor.
Also different architectural styles will use the same type of roof.
In the two examples shown below the wall plans are identical apart from the parapet wall in roof b yet the two roof shapes are quite different as indicated by the roof lines on the plan drawings.