CGAL users discussion list

[Andreas Fabri <>]

Hi Alexandre,

the orientation of the faces is not coherent.
The first face has a halfedge from vertex 0 to 3.
So the fifth face should have the opposite
orientation as it should have a halfedge from
vertex 3  to 0.

It might be a good idea that we reorient
faces automatically.
best,

andreas


On 25/11/2014 20:11, Alexandre Lapene wrote:
> Hi,
>
> I'm struggling opening an off file that I have generated.
> Here is the simple piece of work that does not work
>
>         Polyhedron mesh;
>         std::ifstream input("file.off");
>         if (!input) {
>                 cerr << "Cannot open file!\n";
>                 return EXIT_FAILURE;
>         }
>         if (!(input >> mesh) || mesh.empty()) {
>                 std::cerr << "Not a valid off file." << std::endl;
>                 return EXIT_FAILURE;
>         }
>
> The code exists at the second test as the file is found but appears not
> correct and it's seen as empty.
> Below is my off file
>
> OFF
> 8 6 0
>
> 5.59796 5.80733 -0.000205
> 5.94914 5.35456 -0.000225
> 5.94926 5.35465 0.094035
> 5.59808 5.80742 0.094055
> 5.54866 5.76909 -0.000107
> 5.89984 5.31632 -0.000127
> 5.89996 5.31641 0.094133
> 5.54878 5.76918 0.094153
> 4 0 3 2 1
> 4 4 7 6 5
> 4 1 0 4 5
> 4 3 2 6 7
> 4 0 3 7 4
> 4 1 2 6 5
>
> Just a simple box. I have tried to open it and save it as off in Meshlab but
> it does change the result.
> I have also tried with a cube
>
> OFF
> 8 6 0
>
> 0 1 0
> 0 0 0
> 0 0 1
> 1 0 0
> 1 0 1
> 0 1 1
> 1 1 0
> 1 1 1
> 4  3 4 2 1
> 4  0 6 3 1
> 4  6 0 5 7
> 4  5 0 1 2
> 4  7 5 2 4
> 4  7 4 3 6
>
> It works with this cube.
>
> So, my question is what's wrong with my off file? And is there some debug
> info I can access to know what's wrong in general in one off file I would
> like to open and use
>
> Thanks in advance
>
>
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> --
> View this message in context: 
> http://cgal-discuss.949826.n4.nabble.com/struggling-opening-off-file-tp4660163.html
> Sent from the cgal-discuss mailing list archive at Nabble.com.

--
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri