CGAL users discussion list

[Andreas Fabri <>]

Hello,

On 30/11/2016 08:16, Thomas Holzmann wrote:
> So if I additionally add the cell neighbors and the infinite cells, it
> should work like I did it?

Does tetgen produce a tetrahedrization of the convex hull of the points?
The infinite cells are outside of the convex hull.

You probably also have to set the cell incident to each vertex.

best,

andreas

> Thanks!
>
> Thomas
>
>
> On 11/29/2016 05:26 PM, Andreas Fabri wrote:
> > Not only you are responsible for the neighbor, but CGAL has
> > also the infinite cells, incident to the infinite vertex,
> > in case tetgen has no infinite vertex.
> >
> > andreas
> >
> >
> > On 29/11/2016 17:23, Thomas Holzmann wrote:
> > > Hi all,
> > >
> > > I created a constrained Delaunay triangulation in 3D with Tetgen and
> > > want to convert it now to a CGAL triangulation. As it is no Delaunay
> > > triangulation anymore, I try to create an unrestricted
> > > CGAL::Triangulation_3<CGAL::Exact_predicates_inexact_constructions_kernel,CGAL::Triangulation_data_structure_3<Vbh,
> > >
> > > Cb> > wit the data from the CDT.
> > >
> > > When I use the "normal" insert function to incrementally create the
> > > triangulation, I cannot directly influence the structure of the
> > > triangulation and therefore, as I want to keep the structure, this is
> > > not an option for me (am I right?).
> > >
> > > So I tried to directly add the vertices and cells in the TDS using:
> > >
> > > v1 = cgalTriangulation.tds().create_vertex(cgal_pt);
> > > ...
> > > cell = cgalTriangulation.tds().create_cell(v1, v2, v3, v4);
> > >
> > > However, it seems as if the cells are not added.
> > >
> > > Here are the statistics of the triangulation after adding the data:
> > >
> > > number_of_vertices() = 253792
> > >
> > > number_of_finite_facets () = 0
> > >
> > > number_of_finite_cells () = 0
> > >
> > >
> > > cgalTriangulation.is_valid(true) says:
> > > valid data structure
> > > valid triangulation
> > >
> > > Do I also need to set the cell neighbors and/or facets? Or am I
> > > completely wrong with my approach?
> > >
> > > Any help would be appreciated!
> > >
> > > Thomas
> > >
> > > --
> > > ====================================================
> > > Dipl.-Ing. Thomas Holzmann
> > > TU Graz - Institut fuer Maschinelles Sehen und Darstellen
> > > Graz University of Technology - Institute for Computer Graphics & Vision
> > > Inffeldgasse 16/II, 8010 Graz, Austria
> > >
> > > http://www.icg.tugraz.at/
> > > phone: +43 316 873 5091
> > > ====================================================

--
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri