CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On Thursday 28 January 2010 08:50:40 Simon Perkins wrote:
> Dear All
> 
> Is it possible to perform an exact copy of the vertices and cells between
> two different 3D Triangulation types? For example, I want to use the Mesh_3
> package to tetrahedralize a domain and then copy the Mesh_3 Triangulation
> into a customized Triangulation_3. It doesn't seem possible to do this via
> the constructor, copy() and swap() functions. I also attempted this with
>  the output and input streams, by outputting a Mesh_3 Triangulation and
>  trying to input the same into a Triangulation_3, but this did not work due
>  to a failed assertion.

The problem with "outputing" a triangulation to a file and then reload it 
form 
that file, is that I/O operations in ascii mode usually rounds numbers. It 
has 
the consequence that the reloaded triangulation can be invalid, due to 
geometric inversion of triangles.

To workaround that issue, you can use I/O operations in binary mode. You can 
also set the decimal precision of the output stream to 23 (which is the 
maximum precision for doubles, if I remember well).


-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/