Elevation of section you can select a reference plane to sketch your profile on as long as you have a named one in your model.
Roof by extrusion.
So first of all let s go ahead and create our reference plan.
In the roof reference level and offset dialog select a value for level.
Creates a roof by extruding a profile that you sketch.
Display an elevation 3d or section view.
Specify the work plane.
Click architecture tab build panel roof drop down roof by extrusion.
The highest level in the project is selected by default.
Key points the roof by extrusion tool is used to create wave form type roofs you create a sketch of the upper profile of your roof in a side view i e.