Creating a sloped or cross sloped roof over a non rectangular plan
Its easy in SketchUp to create a sloped roof over a rectangular floor, but creating a slope that is at an arbitrary angle, or creating a slope over a more complex floor shape can be tougher. This video demonstrates an approach to these more complex slope conditions where you draw a large rectangle, position it in place, and then intersect the plane with the model to create your coplanar roof.