You can use the Roof by Picking Points tool to create a roof of a custom size and shape by drawing the basic outline of the roof. This option is ideal when you want the roof to cover only a specific area, such as a porch.
To create a roof by picking points:
Make sure the current location is the location containing the walls you want to insert the roof over.
Select Insert > Roofs > Roof by Picking Points, or click the Roofs button on the Building toolbar and select Roof by Picking Points.
In the catalog, select the roof type you want to insert. Note that the catalog does not contain gable roofs. If you want to create a gable roof, insert a hip roof first, then convert it to a gable.
Select a start point for the roof boundary. Typically you would select an exterior wall corner. Continue selecting points until the boundary is defined. (You do not have to select the start point again because the last point you pick is always closed back to the start point.) See example.
Right-click and select Finish.
Note: If the roof you are inserting runs up against any upper-story walls, the roof will cut around the walls. You can adjust the roof to avoid saddle situations, or to ignore the walls. See Changing the Way a Lower-Story Roof is Created.