Derived Overhang Shapes

Overhang shapes are derived from cylinder shapes and are formed from part of a cylinder's outer perimeter.  When created the overhang shape is placed directly on the cylinder's surfaces.  A typical use is to create a roof style on a half-shape cylinder intended to be a building structure. 

Creating an Overhang Shape

First create a cylinder shape (usually a half-shape), apply any scaling or transformations.
Example cylinder half-shapes

With cylinder shape selected as Object A go to menu Solid: New: Derive Overhang, or use icon on the quick commands bar to open the Derive Overhang dialog.

Resulting overhangs (shown in blue) derived from cylinder shapes

Shaping features on Overhang shapes

With Overhang object selected as Object A use Primitive Shaping panel controls to modify the overhang structure

Note: 'Front', 'Back' refer to negative/positive Y sides of the overhang shape and are relative to the current view position & direction.