CGAL users discussion list

[Monique Teillaud <>]

I would like to stress again the fact that all this is written 
explicitely in the manual --- ref manual, but also user manual, which 
introduces basic choices of representation, to be read before starting.

Also, the stp::pair used to represent a facet is not specific to CGAL.
The triple used for edge is a natural generalization of a pair.

Manuel Caroli wrote:
> Hi Dennis,
>
> Dennis Endt wrote:
> > Last Question:
> >
> > Finite_facets_iterator it:
> > I would like to get the edges of a facet. What`s the correct method for
> > this?
>
> I don't think this is the right question to ask. As you will have 
> figured out from the manual neither edges nor facets are stored 
> explicitly in the data structure.
> So an edge is nothing but a triple (Cellhandle c, int i, int j) where 
> c->vertex(i) and c->vertex(j) are the vertices connected by the edge.
> So if you want to know these endpoints this is the answer to your question.
>
> Be aware of the strong separation between geometric and combinatorial 
> primitives at this point: vertices, edges, facets, and cells are purely 
> combinatorial primitives. That is also the reason why they don't contain 
> geometric information like e.g. coordinates, and why you do not find 
> them in the kernel. On the other hand you have points, segments, 
> triangles, tetrahedra etc. as geometric primitives.
>
> hope this helps
>
> Manuel