CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

Le Vendredi 05 Mars 2010 20:16:56, Ramin H a écrit :
> Hi everyone,
> I have the handle to a facet of a 3D triangulation and would like to find
> the normal vector of the facet. This is how I am doing it but it looks like
> the normal is incorrect.
> 
> // const Facet& f is passed to this function in the function argument ...
> const Point_3& p1 = f.first->vertex((f.second+1)&3)->point();
> const Point_3& p2 = f.first->vertex((f.second+2)&3)->point();
> const Point_3& p3 = f.first->vertex((f.second+3)&3)->point();
> Vector_3 v1 = CGAL::normal(p1, p2, p3);
> 
> Am I missing something?
> 
> -Ramin

Hi Ramin,

Who wrong is the normal vector you get? The computation seems right.

Did you want a *unit* normal vector? Did you want coherent orientations of 
all 
the normal vector you compute?

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