CGAL users discussion list

[Matthieu Chavent <>]

Thank you for your answers.

I use the exact_predicates_inexacte_constructions kernel. I though that 
this kernel was enough to perform what I want: a convex hull of few 
points. I don't create any other points.. The very strange thing is when 
I disable the post conditions, I obtain only triangles as facets of my 
polyhedron so I don't understand why I can have the "strongly_convex" 
error.. The creation of the convex_hull is a part of a bigger program so 
I isolate the part and I try if I obtain the error: if it is the case I 
send the program and the sets of points.

Best Regards,

    Matthieu Chavent


Andreas Fabri a écrit :
> Hello,
>
> Besides the question concerning the kernel you have chosen,
> did you use the static, incremental, or dynamic version.
>
> If the data set is not huge, please send me data set and
> testprogram so that we can reproduce and fix it.
>
> best regards,
>
> andreas
>
>
> Matthieu Chavent wrote:
> > I resolved my problem with compiling with -DCGAL_CH_NO_POSTCONDITIONS
> > and now it's work well but I would like to know how this problem appears
> > and if I disable this option it possible to have concave objects?
> >
> > Thank you in advance!
> >
> > Matthieu Chavent a écrit :
> > > Hello cgal users!
> > >
> > > I performed a convex hull of a set a 3D points. I know that the set 
> > > of points define a convex volume. I use the function 
> > > CGAL::convex_hull_3 on my points list. I  obtain a Polyhedron_3 in 
> > > almost cases but one time a have the error message:
> > >
> > > CGAL error: postcondition violation!
> > > Expr: is_strongly_convex_3(P, traits)
> > > File: /home/Chavent_Matthieu/CGAL-3.2.1/include/CGAL/convex_hull_3.h
> > > Line: 468
> > > Aborted (core dumped)
> > >
> > > It is very strange because I know that the sets of points that form 
> > > the Polyhedron define a convex volume: So, I would like to know if 
> > > somebody had the same problem and How can I get through this error.
> > >
> > > Thank you in advance!
> >
> >
> >
> > ---------------------------
> >
> > Matthieu Chavent
> > LORIA
> > PhD student
> >
> > tel: ++33(0)3-54-95-86-05
> >
> > ---------------------------