CGAL users discussion list

[Helmi Ben Hmida <>]

Hi,
Yes, yes, it will be a closed  polyhedron for sure since also vrml does 
not suport open geometries.
I have tried Bertrand OFF file even u re update, always an empty 
polyhedron !!!

 Am 09.03.2012 10:54, schrieb Nicholas Mario Wardhana:
> On 9 March 2012 17:33, Helmi Ben Hmida
> <>
>   wrote:
> > Hello again,
> > Thanks for your reactions to my mail. I ll try to put u in the big picture.
> > Theses off files are generated from a VRML file containing the set of
> > elements composing a scene.
> > I´´m creating a small parser taking a vrml file as input and generating a
> > set of off files as output correspondinf to the differents geometries
> > existing inside.
> > Unfortuantely, there arealso  duplicates points, but is it here the problem,
> > since even the corrected OFF resent to me does not correspond to a
> > Polydehron.
> >
> > PS: The form is not always a cube, but i´m sure it´s a closed one.
> > PS: Please find one element from the vrml file (if u d like all the vrml
> > file, i can provide it to you)
> > Best
> >
> > Thanks in adavance
> >
> >   DEF Oid806_IfcWall_Wand__Mauerziegel_d_17_5_cm__i
> >   Shape
> >   {
> >    appearance Appearance
> >    {
> >     material Material
> >     {
> >      diffuseColor 0.8 0.8 0.8
> >     } # Material
> >    } # Appearance
> >    geometry IndexedFaceSet
> >    {
> >     ccw    TRUE
> >     convex TRUE
> >     solid  TRUE
> >     coordIndex
> >     [
> >      0 1 2 3 -1,
> >      4 5 6 7 -1,
> >      8 9 10 11 -1,
> >      12 13 14 15 -1,
> >      16 17 18 19 -1,
> >      20 21 22 23 -1
> >     ] # coordIndex
> >     coord Coordinate
> >     {
> >      point
> >      [
> >       19.454456 9.214429 9.195417,
> >       19.454456 9.214429 6,
> >       19.629456 9.214429 6,
> >       19.629456 9.214429 9.195417,
> >       19.629456 9.214429 9.195417,
> >       19.629456 9.214429 6,
> >       19.629456 13.049429 6,
> >       19.629456 13.049429 8.724564,
> >       19.629456 13.049429 8.724564,
> >       19.629456 13.049429 6,
> >       19.454456 13.049429 6,
> >       19.454456 13.049429 8.724564,
> >       19.454456 13.049429 8.724564,
> >       19.454456 13.049429 6,
> >       19.454456 9.214429 6,
> >       19.454456 9.214429 9.195417,
> >       19.454456 9.214429 6,
> >       19.454456 13.049429 6,
> >       19.629456 13.049429 6,
> >       19.629456 9.214429 6,
> >       19.629456 9.214429 9.195417,
> >       19.629456 13.049429 8.724564,
> >       19.454456 13.049429 8.724564,
> >       19.454456 9.214429 9.195417
> >      ] # Point
> >     } # Coordinate
> >     normal Normal
> >     {
> >      vector
> >      [
> >       -0 -1 0,
> >       -0 -1 0,
> >       -0 -1 0,
> >       -0 -1 0,
> >       1 -0 -0,
> >       1 -0 -0,
> >       1 -0 -0,
> >       1 -0 -0,
> >       0 1 0,
> >       0 1 0,
> >       0 1 0,
> >       0 1 0,
> >       -1 0 0,
> >       -1 0 0,
> >       -1 0 0,
> >       -1 0 0,
> >       0 0 -1,
> >       0 0 -1,
> >       0 0 -1,
> >       0 0 -1,
> >       0 0.121862767485053 0.992546959040671,
> >       0 0.121862767485053 0.992546959040671,
> >       0 0.121862767485053 0.992546959040671,
> >       0 0.121862767485053 0.992546959040671
> >      ] # Vector
> >     } # Normals
> >    } # Geometry
> >   } # Shape
> Hi Helmi,
>
> My apology that it seems like my previous e-mail was sent to your
> private inbox, instead of to CGAL mailing list.
>
> Unfortunately I am not familiar enough with VRML to comment on your
> VRML script, but if I understand correctly, your "polyhedron" will be
> nowhere near being closed. Indeed if you manufacture the object, it
> will be closed, but topologically speaking, the existence of boundary
> halfedges in the form of rectangles' bounding edges means that your
> "polyhedron" is just disconnected open meshes. In other words, your
> "polyhedron" is not a polyhedron.
>
> BTW, have you tried Bertrand's OFF file? Although I suppose the second
> line should have been "8 6 12" (without the double quotes).
>
> Best regards,
> Nicholas