CGAL users discussion list

[Andreas Fabri <>]

There is a symbolic vertex at infinity with a cell per triangle
face on the convex hull.

When you use the constructor or insert function with
an iterator range the points get sorted along a
space filling curve.  If you insert them point bty
point it should maintain your order.

andreas


 wrote:
> I am trying to use CGAL in some program. I tried to compute simple example to 
> understand structure of the results which CGAL gives. This example was 
> Delaunay triangulation of pyramid with vertices
>   1  0  0
>   0  1  0
>  -1  0  0
>   0 -1  0
>   0  0  1  .
>
> CGAL has given results
>
> 5
>   0  0  1
>  -1  0  0
>   0  1  0
>   1  0  0
>   0 -1  0
> 8
>   0 1 3 4
>   3 2 1 0
>   2 1 0 5
>   5 1 0 4
>   5 0 3 4
>   1 5 3 4
>   1 2 3 5
>   2 0 3 5
>
> The list of cells created by CGAL contains six various indices (0..5) into  list of vertices. But the list of vertices contains only five vertices. I don’t understand correspondence between the indices and the vertices. 
>
> The list of vertices contains vertices in different order than is the order in which I inserted them into list of points from which triangulation is constructed. I don’t know if I have made some mistake during insertion of vertices into the list or the different order has some meaning. 
>
> Arnost Vecerka