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[Adam Hopkins <>]

Hi Daniel and Sebastien:

Again, thank you for your answers. When I say external vertexes, I am refering to all vertexes in external faces, is to say: using the example code of my first email, I can compute the external cells of a triangulation, and each of them has an external face defined for three vertexes, which are the external vertexes.

For example assume that I have a triangulation of a sphere, I want to know which are the vertexes in the external surface. Please, see the code in my first email for more references.

thank in advance and waiting suggestions

A.

On Mon, Jan 30, 2012 at 3:58 PM, Sebastien Loriot (GeometryFactory) <> wrote:

What is your definition of external vertices?

Sebastien.

On 01/30/2012 03:41 PM, Adam Hopkins wrote:

Hi Daniel:

Thank you for your help, but I think that it is not the correct way to
solve my problem. When the convex hull is computed not all the external
vertexes are included. For this reason, I need other form to know which
are the real external vertexes of a triangulation.

Regards and waiting more suggestions
A.

On Mon, Jan 30, 2012 at 3:29 PM, Daniel Duque <

<mailto:>> wrote:

   On Monday 30 January 2012 15:20:52 Adam Hopkins wrote:
    > Hi all,
    >
    > Thank you for your previous answers, but I have a last issue
   related with
    > triangulations.
    >
    > Using the example code below, I can know which are the external
   cells of a
    > triangulations, but I also need to know which are the external
   vertex of
    > the same triangulation.

   I guess you mean the vertices that form the convex hull. Have a look
   here:

   http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_2/Chapter_main.html#Subsection_36.4.2

   Best,

   Daniel


    > Is there any form to know which are the external
    > facets of each of these cells in order to know which are the most
   external
    > vertexes of this triangulation?
    >
    > Concretely, How Can I know which are the external vertices of a
    > triangulation?
    >
    > std::vector<Cell_handle> infinite_cells;
    > T.incident_cells(T.infinite_vertex(),
   std::back_inserter(infinite_cells));
    >
    > for(int ii = 0; ii < (int)infinite_cells.size(); ii++)
    > {
    > Cell_handle c = infinite_cells[ii];
    > Cell_handle e = c->neighbor(c->index(T.infinite_vertex()));
    > }
    >
    > Regards and thank you for all
    > A.

   --
   http://dcain.etsin.upm.es/~daniel

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