CGAL users discussion list

["François-Xavier Coudert" <>]

Sorry for the first email, which was incomplete. I didn't even quote the 
error message! The code described below compiles OK, but when run it gives:

CGAL error: assertion violation!
Expression : 
File       : /opt/CGAL-3.9/include/CGAL/Skin_surface_base_3.h
Line       : 483
Explanation: intersection: no intersection.


Can someone help me track down that issue?

Thanks in advance,
FX






Le 29 nov. 2011 à 13:05, FX a écrit :

> Dear CGAL team and users,
> 
> I have encountered an assertion violation in CGAL's meshing the union of a 
> set of balls. I have reduced my much larger original code to a minimal 
> testcase that always fails on my system. The following testcase tries to 
> mesh the union of 4 balls:
> 
>> #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
>> #include <CGAL/Skin_surface_3.h>
>> #include <CGAL/Union_of_balls_3.h>
>> #include <CGAL/Polyhedron_3.h>
>> #include <CGAL/mesh_skin_surface_3.h>
>> #include <CGAL/subdivide_skin_surface_mesh_3.h>
>> #include <CGAL/IO/Polyhedron_iostream.h>
>> 
>> int main (void)
>> {
>> typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
>> typedef CGAL::Skin_surface_traits_3<K> Traits;
>> typedef CGAL::Union_of_balls_3<Traits> Skin_surface_3;
>> typedef Skin_surface_3::FT FT;
>> typedef Skin_surface_3::Weighted_point Weighted_point;
>> typedef Weighted_point::Point Bare_point;
>> typedef CGAL::Polyhedron_3<K, 
>> CGAL::Skin_surface_polyhedral_items_3<Skin_surface_3> > Polyhedron;
>> 
>> std::list<Weighted_point> list;
>> list.push_front(Weighted_point(Bare_point(0.30700,  6.45800,  6.45800), 
>> 1)); 
>> list.push_front(Weighted_point(Bare_point(0.07400,  5.03900,  5.03900), 
>> 1)); 
>> list.push_front(Weighted_point(Bare_point(0.30700, 19.37400, 19.37400), 
>> 1)); 
>> list.push_front(Weighted_point(Bare_point(0.07400, 20.79300, 20.79300), 
>> 1)); 
>> 
>> Polyhedron p;
>> Skin_surface_3 skin_surface(list.begin(), list.end());
>> CGAL::mesh_skin_surface_3(skin_surface, p);
>> CGAL::subdivide_skin_surface_mesh_3(skin_surface, p, 1);
>> 
>> std::cout << "Mesh has " << p.size_of_facets() << " facets" << std::endl;
>> 
>> return 0;
>> }
> 
> I compile it against CGAL-3.9 on a x86_64 Mac OS 10.7 system, with Apple's 
> default G++ 4.2.1 compiler. Boost is 1.46.1, GMP is 5.0.2, MPFR is 3.1.0 (+ 
> available patches). The compilation command-line is:
> 
>> g++ bug.cpp -I/opt/CGAL-3.9/include -I/opt/boost-1.46.1/include 
>> -L/opt/CGAL-3.9/lib -lCGAL -L/opt/boost-1.46.1/lib -lboost_thread -lmpfr 
>> -lgmp -frounding-math && ./a.out
> 
> 
> I hope you can help me understand what's going wrong, and whether I used 
> the CGAL functions right (I tried to stick to the examples as much as 
> possible).
> 
> Thanks in advance,
> FX Coudert
> 
> 
> 
> PS: the CGAL doc says that GMP and MPFR are recommended, implying that 
> building without them is possible. However, when I tried to do so, the 
> build system complains that CGAL_Core depends on GMP, and compilation will 
> not succeed. Did I miss something?

-- 
Dr. François-Xavier Coudert
CNRS & Chimie ParisTech
http://www.chimie-paristech.fr/molsim/
Phone: +33 1 44 27 65 99 / +33 6 28 04 58 18