CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Hamid G wrote:
> On Mon, Nov 14, 2011 at 8:38 AM, Sebastien Loriot (GeometryFactory)
> <>
>  wrote:
> > What do you want to do precisely?
> > A simple translation of the points in the mesh?
>
> Yes, just offset them by a fixed (x0, y0, z0).

You can directly hack weighted points in vertices of the underlying
regular triangulation.

Here is an example code, assuming your kernel is K:

typedef C3t3::Triangulation::Weighted_point Weighted_point;
typrdef C3t3::Triangulation::Finite_vertices_iterator Vertices_iterator;

for (Vertices_iterator itv=c3t3.triangulation().finite_vertices_begin(), 

                     itv_end=c3t3.triangulation().finite_vertices_end();
     itv!=itv_end;++itv)
{
  itv->point()=
    Weighted_point(itv->point().point()+K::Vector_3(x0,y0,z0),
                   itv->point().weight());
}



Related documentation pages are here:
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3_ref/Concept_MeshComplex_3InTriangulation_3.html
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Triangulation_3_ref/Class_Regular_triangulation_3.html

Note that using offset in this context is confusing because it might
refer to the offset of a solid for example, whereas "translate" is
the perfect word here.

Sebastien.

> > > I am using CGAL to create tetrahedral meshes off of grayscale images.
> > > After mesh is generated I need to translate the vertices to match
> > > coordinate system of
> > > the imaging machine (MRI, CT, ...)
> > >
> > > I do this by adding a fixed offset point(x,y,z) to all vertices in a
> > > post-processing step
> > > outside CGAL using the MEDIT file.
> > >
> > > I was wondering if this can be done within CGAL/C++ so I don't have to use
> > > Matlab/Python to perform this step.
> > >
> > > thanks in advance,
> > > Hamid
> >
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