CGAL users discussion list

[Helmi Ben Hmida <>]

Hi Philipp,
Thanks for u re replay,
In fact, I want to write an off file onto a Polydehron. Unfortuantely, 
at the beganning, we don´t have theses OFF files, just we have a VRML 
and x3d file that we re converting to OFF files. We have made a forst 
attempt to convert the faces of the VRML to OFF, but, we re getting 
always an empty Polyhderon, based on Nicholas´s suggestions,  it works 
with a triangulated faces, just with this compbination (see example). I 
tried to simulate others faces combination, but getting an empty Polyhderon.
The question was, is there some specific restrictions, or algorithm to 
create theses faces.

Hpepefully that it´s clear

Thanks in advance for u re help, we r blocked here for 2 weeks

Am 14.03.2012 23:40, schrieb Philipp Moeller:
> Helmi Ben 
> Hmida<>
>   writes:
>
> > Hello every Body,
> > I´m trying to weel create the edges in an OFF files respecting this
> > template (functional example) in order to convert it to a
> > polyderon. To do, an algorithm creating edges has to be automatically
> > implemented.
> > The standard example sent is this one
> > OFF
> > 8 10 0
> > 19.454456 9.214429 9.195417
> > 19.454456 9.214429 6
> > 19.629456 9.214429 6
> > 19.629456 9.214429 9.195417
> > 19.629456 13.049429 6
> > 19.629456 13.049429 8.724564
> > 19.454456 13.049429 6
> > 19.454456 13.049429 8.724564
> > 3 0 1 2
> > 3 2 3 0
> > 3 3 2 4
> > 3 4 5 3
> > 3 5 4 6
> > 3 6 7 5
> > 3 7 6 1
> > 3 1 0 7
> > 3 3 5 7
> > 3 7 0 3
> > 3 7 0 3
> >
> >
> > The problem is with the 4 last edges, is there any relations between
> > them to be created automatically by an algorithm, since we have a
> > verayty of 3D points number (not always 8)
> >
> > Thanks in advance
> > H.
> It's hard to understand what you want to do. Do you want to read or
> write an OFF file from or into a Polyhedron? Polyhedron overloads
> operator<<  and operator>>  for those tasks [1].
>
> If this has absolutely no relevance to your question, I misunderstood
> you.
>
> HTH,
> Philipp Moeller
> GeometryFactory
>
> [1] : 
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Polyhedron/Chapter_main.html#Section_25.4