CGAL 5.1.3  3D Alpha Shapes

#include <CGAL/Fixed_alpha_shape_vertex_base_3.h>
Vb.
The class Fixed_alpha_shape_vertex_base_3
is the default model for the concept FixedAlphaShapeVertex_3
.
Traits  is the geometric traits class that is provided to the Alpha_shape_3 class. 
Vb  must be a vertex base class adapted to the type of triangulation that is being used. By default, it is instantiated with Triangulation_vertex_base_3<Traits> , which is appropriate for basic alpha shapes. 