CGAL users discussion list

Section 1 of the user manual of 3D Triangulation is about 
representation, and it says just after a few lines
---------
As in the underlying combinatorial triangulation (see Chapter 28), edges 
(1-faces) and facets (2-faces) are not explicitly represented: a facet 
is given by a cell and an index (the facet i of a cell c is the facet of 
c that is opposite to the vertex with index i) and an edge is given by a 
cell and two indices (the edge (i,j) of a cell c is the edge whose 
endpoints are the vertices of c with indices i and j). See Figure 28.1.
---------
and this is written again in the introduction of the ref manual

And the typedef for Facet, mentioned by Laurent in his answer, is 
documented at the beginning of the ref manual of Triangulation_3 and TDS_3.

So, for this precise question, I think there is no way the manual could 
give a better answer.

Andreas Fabri wrote:
> Hi Matthieu,
>
> My question about the quality of the documentation was serious.
> Did you happy programming before reading the documentation (what
> I admittedly often do), or did you try to find it in the manual,
> and gave up after a couple of minutes?
>
> andreas
>
>
> Matthieu Chavent wrote:
>
> > Thanks to Andreas Fabri and Laurent Rineau and sorry for neewbies 
> > questions.
> >
> > Regards,
> >
> >          Matthieu Chavent.
> >
> > Laurent Rineau a écrit :
> >
> > > On Tuesday 16 October 2007 17:16:07 Matthieu Chavent wrote:
> > >  
> > >
> > > > Good afternoon,
> > > > I use triangulation_3 and and use a facet_iterator. I would like to 
> > > > know
> > > > if it possible to retrieve from a facet the two cell_handles of the two
> > > > cells which  have the facet in common, in a simple manner.
> > > >     
> > >
> > >
> > > Well, I quote here the definition of Facet, from the reference page 
> > > "TriangulationDataStructure_3":
> > >
> > > "typedef std::pair<Cell_handle, int> Facet;
> > >        (c,i) is the facet of c opposite to the vertex of index i."
> > >
> > > So, if "f_it" is a facet iterator, "f_it->first" is one of the two 
> > > cells you request, and "f_it->first->neighbor(f_it->second)" is the 
> > > other one (see the reference page 
> > > "TriangulationDataStructure_3::Cell" for a description of 
> > > Cell::neighbor).
> > >
> > > Best regards,
> > >
> > >