CGAL users discussion list

> as.get_alpha_shape_cells(back_inserter(cells), Alpha_shape_3::EXTERIOR);
> Could anybody, please, clarify the meaning of this flag in the context of
> 3D Alpha Shape?
It means "those cells that are in the delaunay complex of my point cloud
but are not in the alpha complex for the current alpha". There is a third
argument "a" wich defaults to "this->alpha()" if you want to specify
anoter "level".
In other words you could also say "those cells in the Delaunay complex for
wich there is no sphere with a smaller radius than alpha^2 whose border
contains the four vertices".

> Do these cells logically contribute to the volume of the alpha shape?
No