CGAL users discussion list

[Andreas Fabri <>]

On 03/06/2015 13:12, Mauricio Diaz wrote:
> Thanks Andreas,
> > The AABB tree is only worth it if you have many query segments.
> Yes, that's my case!
>
> > A third alternative is to locate an endpoint in the triangulation
> > and to walk towards the other end point collecting the cells
> > you traverse.
> This alternative sounds interesting. What do you mean with "walk towards"? 
> How can this be done?

When you are in a cell, you determine which of the four faces
is interesected by your segment. You jump to the neighbor cell
and so on.  Note that you might not intersect a single face
but an edge or a vertex.

andreas

> Thanks again,
>
> - Mauricio
>
> ----- Mail original -----
> > De: "Andreas Fabri" 
> > <>
> > À: 
> >
> > Envoyé: Mercredi 3 Juin 2015 11:40:44
> > Objet: Re: [cgal-discuss] Intersection segment and cells from 3D Delaunay 
> > triangulation
> >
> >
> > The AABB tree is only worth it if you have many query segments.
> >
> > A third alternative is to locate an endpoint in the triangulation
> > and to walk towards the other end point collecting the cells
> > you traverse.
> >
> > andreas
> >
> > On 03/06/2015 11:28, Mauricio Diaz wrote:
> > > Hi,
> > > I wonder how to calculate the intersections between a 3D segment and
> > > some cells from a 3D Delaunay triangulation.
> > >   From the documentation, I understand two ways to do it:
> > > - By iterating all over the finite cells of the 3D triangulation and
> > > calculating CGAL::intersection(segment, cell)
> > > - By construction an AABB tree of the cells (the triangle facets) and
> > > finding the intersections with the segment.
> > >
> > > Which of these two options is more efficient? Any different suggestion?
> > > Thanks,
> > >
> > >
> > > - Mauricio DIAZ
> >
> > --
> > Andreas Fabri, PhD
> > Chief Officer, GeometryFactory
> > Editor, The CGAL Project
> >
> > phone: +33.492.954.912    skype: andreas.fabri
> >
> > --
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--
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri