CGAL users discussion list

[Laurent Saboret <>]

Hi Paulo,

The first step to use CGAL surface mesh parameterization is to convert 
your data to CGAL Polyhedron_3 
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Polyhedron/Chapter_main.html

You have several ways :
* Save your data in a .OFF file and let Polyhedron_3 read it (the 
easiest) 
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Polyhedron/Chapter_main.html#Section_23.4
* Convert your data by code (as you started below) using Euler 
operations 
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Polyhedron/Chapter_main.html#Subsection_23.3.7
* Convert your data by code using Polyhedron_incremental_builder_3 
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Polyhedron/Chapter_main.html#Subsection_23.6.2

Best regards,
Laurent Saboret



 wrote:
> Hello,
>
> I'm using CGAL's parameterization package.
> There's a very nice page explaining how to use if with OFF files, but that's
> not my case.
> So, instead of loading a mesh from a file, I'm trying to pass my vertices and
> faces to CGAL.
>
> My data is formatted in a opengl typical pattern. I have a vertex array, one 
> or
> more arrays of triangular faces. These faces contain no more than indexes to
> the vertex array.
>
> What I'm doing is to pass the face like:
> typedef CGAL::... Poly;
> Poly poly;
> for all my faces 
>     get the face vertexes (pa, pb and pc)
>     poly.make_triangle(Point(pa.x, pa.y, pa.z), Point(pb.x, pb.y, pb.z),
> Point(pc.x, pc.y, pc.z));
>
> Of course this repeats vertexes (points), and does not give any information
> about the faces connectivity.
> In the end, running the algorithm I get: "Parameterization requires a convex
> border"
> The mesh I'm using right now is just a couple of coplanar triangles, or if you
> want, a tessellated unit square.
>
> But I can't seem to be able to find how to pass the vertexes and the faces
> separately.
> Nor do I know how to specify the border.
> Is there an example of this somewhere?
> I am searching the examples and demos, but some help would be greatly
> appreciated.
>
> Thank you
> Paulo
>
>   

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