CGAL users discussion list

["Joe C" <>]

Hi, everyone,

I am testing a simple I/O function of Polyhedron_3. I found that the output has different results from the input. Here is the pseudo code:

// a polyhedron
Polyhedron_3 poly;

// some construction work, not listed....

// test closeness and validity before output
poly.is_closed(); // true
poly.is_valid(); // true

// output
std::ofstream SaveFile("output.off");
SaveFile << poly;
SaveFile.close();

// read in output
poly.clear();
OpenFile.open("output.off");
OpenFile >> poly;
OpenFile.close();

// test closeness and validity after output
poly.is_closed(); // true
poly.is_valid(); // false, different from original one

Notice that the polyhedron "poly" after reading in the output is no longer valid.

Is this CGAL bug or am I missing something here ? My guess is that somehow it messed up because of some numerical problem. I am using Exact_predicates_exact_constructions_kernel.

P.S. if I read in some ".off" model into Polydedron_3, do I lose the original validity of the model as well?

Thanks.
Joe