1) The option to remove INTERNAL edges from the faces of the result of Offset operati...

1) The option to remove INTERNAL edges from the faces of the result of Offset operation has been added into Offset API.
By default these edges will be kept in the result.
To remove these edges make sure to set the corresponding flag to TRUE when initializing the Offset algo.

void BRepOffset_MakeOffset::Initialize(const TopoDS_Shape&    S,
                                       const Standard_Real    Offset,
                                       const Standard_Real    Tol,
                                       const BRepOffset_Mode  Mode,
                                       const Standard_Boolean Inter,
                                       const Standard_Boolean SelfInter,
                                       const GeomAbs_JoinType Join,
                                       const Standard_Boolean RemoveIntEdges,
                                       const Standard_Boolean Thickening)

2) Due to the small inaccuracy of the calculation of the bi-normal direction (direction inside the face on the edge) the criterion on the coincidence of these directions has been weakened.

3) Make the possibility to produce empty result in case of any invalidity (spikes, self-intersections, faces inversion) optional.