You can use slope arrows to create slopes on a roof. See Creating a Sloped Surface Using a Slope Arrow.
The following example shows a roof that you can create in Revit using a slope arrow.

Creating a Roof with Different Eave Heights
You can create a roof with slope-defined lines at different elevations by joining 2 separate roofs.

(Finish Edit Mode). 
(Finish Edit Mode).
Geometry panel
(Join/Unjoin Roof). 

You now have a single roof with different eave heights.

Finished house in a rendered view
Creating a Four-Sided Gable Roof
Use slope arrows to create a 4-sided gable roof.


Draw panel
(Slope Arrow). 
(Finish Edit Mode). 
Completed roof

Completed roof on a model