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[Manuel Bourgault <>]

Thank you for your answer, i will post the points.

Before that, can you tell me what this error mean ? I juste dont understand

Le 2014-09-10 01:19, "Sebastien Loriot (GeometryFactory)" <> a écrit :

Posting the point set would indeed help.

Sebastien

On 09/09/2014 10:33 PM, manuelB wrote:

Hello everybody,

I discovered CGAL a couple of weeks ago, very great library !
I needed something that can build mesh from a set of points (also heard
about the normal things..). So, i installed it on my Ubuntu machine.
I succeed compiling the "poisson reconstruction example" using the
kitten.xyz file, works really great !

My problem appears when I try to use my own custom .xyz file..
Basically, this is what i have done:
  - I wrote an STL file importer ( i get face list with normals )
  - I wrote a simple algorythm that creates a set of points
    from those faces and compute their normals from the
    corresponding faces wich touches that point in the stl file.
  - OK, now I have a set of points with normals..

          --  Here comes CGAL --

  - I ran the simple example for poisson processing ( the same
    I tried with the kitten.xyz file... and voila:

             terminate called after throwing an instance of
'CGAL::Precondition_excpetion'
                 what():   CGAL_ERROR: precondition violation!
             Expr: dimesion() == 3
             File: /usr/include/CGAL/Triangulation_3.h
             Line: 463

The first thing i was thinking was that my set of point was probably wrong,
so i started thinking.. The output file of the kitten.xyz (kitten.off) was
really small
and maybe thats because my points were representing a mesh that was too big
!
No luck... Same error.

After that, I tried writing a .xyz file to see if the
CGAL::read_xyz_points_and_normals()
does something I wasnt doing when I was copying the points.
Same error..

The code above is the same as the example:


/* CGAL INCLUDES */
#include <CGAL/trace.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/IO/Polyhedron_iostream.h>
#include <CGAL/Surface_mesh_default_triangulation_3.h>
#include <CGAL/make_surface_mesh.h>
#include <CGAL/Implicit_surface_3.h>
#include <CGAL/IO/output_surface_facets_to_polyhedron.h>
#include <CGAL/Poisson_reconstruction_function.h>
#include <CGAL/Point_with_normal_3.h>
#include <CGAL/property_map.h>
#include <CGAL/IO/read_xyz_points.h>
#include <CGAL/compute_average_spacing.h>
#include <CGAL/Vector_3.h>

#include <CGAL/pca_estimate_normals.h>
#include <CGAL/mst_orient_normals.h>
#include <CGAL/property_map.h>
#include <CGAL/IO/read_xyz_points.h>

/* standard C++ includes */
#include <utility> // defines std::pair
#include <vector>
#include <fstream>

// usefull types
typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef Kernel::FT FT;
typedef Kernel::Point_3 Point;
typedef Kernel::Vector_3 Vector;
typedef CGAL::Point_with_normal_3<Kernel> Point_with_normal;
typedef Kernel::Sphere_3 Sphere;
typedef std::vector<Point_with_normal> PointList;
typedef CGAL::Polyhedron_3<Kernel> Polyhedron;
typedef CGAL::Poisson_reconstruction_function<Kernel>
Poisson_reconstruction_function;
typedef CGAL::Surface_mesh_default_triangulation_3 STr;
typedef CGAL::Surface_mesh_complex_2_in_triangulation_3<STr> C2t3;
typedef CGAL::Implicit_surface_3<Kernel,Poisson_reconstruction_function>
Surface_3;

// Point with normal vector stored in a std::pair.
typedef std::pair<Point, Vector> PointVectorPair;


int main()
{
     FT sm_angle = 20.0; // Min triangle angle in degrees.
     FT sm_radius = 30; // Max triangle size w.r.t. point set average
spacing.
     FT sm_distance = 0.375; // Surface Approximation error w.r.t. point set
average spacing.

     PointList points;
     std::ifstream stream("/home/manuel/Desktop/points.xyz");
     if (!stream ||
     !CGAL::read_xyz_points_and_normals(
     stream,
     std::back_inserter(points),

CGAL::make_normal_of_point_with_normal_pmap(std::back_inserter(points))))
     {
         std::cerr << "Error: cannot read file points.xyz" << std::endl;
         return -1;
     }

     CGAL::make_normal_of_point_with_normal_pmap(std::back_inserter(points));

     Poisson_reconstruction_function function(points.begin(), points.end(),
         CGAL::make_normal_of_point_with_normal_pmap(points.begin()));

     **** ERROR HAPPEN HERE ****
     if (!function.compute_implicit_function()) *** <----- ***
     {
         return -1;
     }

     // Computes average spacing
     FT average_spacing = CGAL::compute_average_spacing(points.begin(),
points.end(), 6 /* knn = 1 ring */);

     Point inner_point = function.get_inner_point();
     Sphere bsphere = function.bounding_sphere();
     FT radius = std::sqrt(bsphere.squared_radius());

     FT sm_sphere_radius = 5.0 * radius;
     FT sm_dichotomy_error = sm_distance*average_spacing/1000.0; // Dichotomy
error must be << sm_distance

     Surface_3 surface(function,
         Sphere(inner_point,sm_sphere_radius*sm_sphere_radius),
         sm_dichotomy_error/sm_sphere_radius);

     CGAL::Surface_mesh_default_criteria_3<STr> criteria(sm_angle, // Min
triangle angle (degrees)
         sm_radius*average_spacing, // Max triangle size
         sm_distance*average_spacing); // Approximation error

     STr tr; // 3D Delaunay triangulation for surface mesh generation
     C2t3 c2t3(tr); // 2D complex in 3D Delaunay triangulation

     CGAL::make_surface_mesh(c2t3, // reconstructed mesh
         surface, // implicit surface
         criteria, // meshing criteria
         CGAL::Manifold_with_boundary_tag());

     if(tr.number_of_vertices() == 0)
         return -1;

     std::ofstream out("/home/manuel/Desktop/points.off");
     Polyhedron output_mesh;
     CGAL::output_surface_facets_to_polyhedron(c2t3, output_mesh);

     out << output_mesh;

     return 0;
}

--------------------------------------------------------------------------------------------------

I dont know was i am doing wrong, and tobe honnest I have
absolutly no idea about the meaning of this error. Thank you
for your time.

PS: i can post the points.xyz file if wanted.





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