CGAL users discussion list

[Daniel Russel <>]

> >  Surface_3 surface(ellipsoid_function, // pointer to function
> >                  Sphere_3(CGAL::ORIGIN, 3.5)); // bounding sphere
>
> Your bounding sphere is defined with a *squared* radius of 3.5, and  
> clearly
> that sphere does not bound the surface. In my opinion, you need at  
> least 10 as
> *squared* radius of the sphere.
>
> http://www.cgal.org/Manual/3.4/doc_html/cgal_manual/Kernel_23_ref/Class_Sphere_3.html
As someone who gets bitten by this periodically when using the surface  
mesher, I would really appreciate if there is were a test in the code  
which could give a better error message if you mess this up. Many  
spheres provided by other libraries use radius and even the min sphere  
of spheres in CGAL does, so it is a quite easy mistake to make.  
Especially since the surface mesher is particularly likely to be used  
without heavy use of the rest of the CGAL library.

Perhaps a test when the sphere is used to prevent a point from being  
added. Find a nearby point on the sphere and make sure that it is on  
the correct side of the isosurface.