CGAL users discussion list

[Andreas Fabri <>]

Hello,

The coordinates must be integers. In your case they are
all rounded to 0 or 1.

andreas



 wrote:
> Hello,
>
>
> I'm unsuccessfully trying to create Nef_Polyhedron_3 object from Polyhedron_3, which is in turn read form cube.off file. 
>
> It turns out that when the coordinates of the vertices (by abs value) are 
> smaller than one, I receive segmentation fault, or some other kind of error, 
> which depends on Kernel that is used.
>
> Same problem appears when I start nef_3 demo. Using following syntax:
>
> $./nef_3 loadoff cube01.off
>
>
> I receive the following error:
>
> Error !!!!!!!!!!!!!!!!!!!!!!!
> Error !!!!!!!!!!!!!!!!!!!!!!!
> Error !!!!!!!!!!!!!!!!!!!!!!!
> Error !!!!!!!!!!!!!!!!!!!!!!!
> Error !!!!!!!!!!!!!!!!!!!!!!!
> Error !!!!!!!!!!!!!!!!!!!!!!!
> wrong cycle
>   PointH3(0, 0, 0, 1)
>   PointH3(0, 0, 0, 1)
>   PointH3(0, 0, 0, 1)
>   PointH3(0, 0, 0, 1)
> CGAL error: assertion violation!
> Expr: !pe_prev->facet()->plane().is_degenerate()
> File: /usr/local/CGAL/include/CGAL/Nef_3/polyhedron_3_to_nef_3.h
> Line: 149
> Aborted
>
>
>
> The file cube01.off is same as cube.off, found in demo/Nef_3 directory, 
> except for the scaled coordinates of vertices:
> OFF
> 8 6 0
> # vertices
>  -0.1 -0.1  0.1
>  -0.1  0.1  0.1
>   0.1  0.1  0.1
>   0.1 -0.1  0.1
>  -0.1 -0.1 -0.1
>  -0.1  0.1 -0.1
>   0.1  0.1 -0.1
>   0.1 -0.1 -0.1
> # facets
>   4  3 2 1 0
>   4  0 1 5 4
>   4  6 5 1 2
>   4  3 7 6 2
>   4  4 7 3 0
>   4  4 5 6 7
> #-----------------------------
>
>
> Program that triggers same behavior is modified version from users manual:
> //----------------------cut-----------------
> // *read Polyhedron_3 from std::cin, 
> // *convert it into Nef_Polyhedron_3
> //
> #include <CGAL/Gmpz.h>
> #include <CGAL/Cartesian.h>
> #include <CGAL/Homogeneous.h>
> #include <CGAL/Extended_homogeneous.h>
> #include <CGAL/Nef_polyhedron_3.h>
> #include <CGAL/Polyhedron_3.h>
> #include <CGAL/IO/Polyhedron_iostream.h>
> #include <CGAL/IO/Nef_polyhedron_iostream_3.h>
> #include <fstream>
>
> typedef CGAL::Gmpz  NT;
> //typedef CGAL::Homogeneous<NT>  SK;
> typedef CGAL::Cartesian<double> SK;
> typedef CGAL::Extended_homogeneous<NT>  EK;
> typedef CGAL::Nef_polyhedron_3<SK>  Nef_polyhedron_S;
> //typedef CGAL::Nef_polyhedron_3<EK>  Nef_polyhedron_E;
>
> typedef CGAL::Polyhedron_3<SK>        Polyhedron;
>
> int main() {
>
>   //  debugthread=29;
>   Polyhedron P;
>
>   std::cin >> P;
>
>   Nef_polyhedron_S S(P);
>   std::cout << S;
>
> }
> //----------------cut--------------
>
>
>
> Am I missing something?
>
>
>
>
> Thanks in advance, 
>
> Gordan Sikic