CGAL users discussion list

[Bob Bill <>]

Dear all,

I notice that if I compute the volume bounded by a Surface_mesh with CGAL::Polygon_mesh_processing::volume(surface_mesh)

I have a result that is different w.r.t what I get if I first mesh the inside and then sum the volume of each tetrahedron, i.e. 

using K = CGAL::Exact_predicates_inexact_constructions_kernel;

using Triangulation_3 = CGAL::Triangulation_3<K>;

double sum =0.;

Triangulation_3 tria;

tria.insert(sm.points().begin(), sm.points().end());

for (const auto &c : tr_q.finite_cell_handles())

{

const auto &tet = tr_q.tetrahedron(c);

sum += std::abs(tet.volume());

}

What is the reason for that? I spent a whole day but I really cannot figure it out. 

Best, BoB