CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 10/30/2013 06:08 PM, Marius Kintel wrote:
> On 2013-10-30, at 12:41 PM, KeithSloan52 
> <>
>  wrote:
> > But I am still a bit confused because OpenSCAD seems to be making the same
> > call to Convex_hull, but when viewing its output the facets look to be
> > mostly 4 sided.
> Could it be that the 4-sided faces you see is an illusion due to CGAL 
> providing separate edge information, which we use to render edges?
>
> See CGAL/Nef_polyhedron_3.h:561, CGAL/Nef_3/SCN_external_structure.h and 
> CGAL/Nef_3/SNC_simplify.h which could be responsible for this edge 
> construction. The code is really hard to read and as far as I can see not 
> documented, but perhaps someone here knows what's going on..
>
>   -Marius
As I said Nef_3 removes non-necessary edges. That is if two incident 
triangles are in the same plane, the common edges will be removed.

Sebastien.