## CGAL::Arr_face_overlay_traits<Arr_A,Arr_B,Arr_R,OvlFaceData>

### Definition

An instance of *Arr_face_overlay_traits<Arr_A,Arr_B,Arr_R,OvlFaceData>* should be used for overlaying two arrangements
of types *Arr_A* and *Arr_B*, which are instantiated using the same
geometric traits-class and with the DCEL classes *Dcel_A* and
*Dcel_B* respetively, in order to store their overlay in an arrangement
of type *Arr_R*, which is instantiated using a third DCEL class
*Dcel_R*. All three DCEL classes are assumed to be instantiations of the
*Arr_face_extended_dcel* template with types *FaceData_A*,
*FaceData_B* and *FaceData_R*, respectively.

This class gives empty implementation for all overlay traits-class functions,
except the function that computes the overlay of two faces. In this case,
it uses the functor *OvlFaceData*, which accepts a *FaceData_A* object
and a *FaceData_B* object and computes a corresponding *FaceData_R*
object, in order to set the auxiliary data of the overlay face.

*#include <CGAL/Arr_default_overlay_traits.h>*

### Is Model for the Concepts

*OverlayTraits*

### See Also

*overlay*

*CGAL::Arr_face_extended_dcel<Traits,FData,V,H,F>*