After defining the dormer, the angles of the surfaces that make up the dormer roof can be edited with the Change Dormer Roof Angles command.
Click the Change Dormer Roof Angles icon from the dormer toolbar .
Roof angle modification is valid for single, double and triple dormer objects.
There is no surface angle in round and spline types. Click one of these objects.
A dialog will open where you can change the angle of the surface according to the dormer type you selected.
Enter values in degrees or percentages in the dialog.
Click the OK button.