CGAL: How to get segmentation within polyline like CGAL Demo does?

Question

I have a surface mesh with some sharp features. I want segment the mesh within the polyline composed of these features. In CGAL Demo, "Detect Sharp Features" function can fulfill my requirement, as the pic shows. Right now, I can get the polyline with domain.detect_features() which calls add_features_from_split_graph_into_polylines() internally. But how can i get the surface patch inside the polyline and cut them? CGAL Demo Result

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Mesh_triangulation_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>
#include <CGAL/Polyhedral_mesh_domain_with_features_3.h>
#include <CGAL/make_mesh_3.h>
#include <CGAL/IO/output_to_vtu.h>

#include <CGAL/IO/facets_in_complex_3_to_triangle_mesh.h>
#include <CGAL/Surface_mesh.h>


// Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Mesh_polyhedron_3<K>::type Polyhedron;
typedef CGAL::Polyhedral_mesh_domain_with_features_3<K> Mesh_domain;
#ifdef CGAL_CONCURRENT_MESH_3
typedef CGAL::Parallel_tag Concurrency_tag;
#else
typedef CGAL::Sequential_tag Concurrency_tag;
#endif
// Triangulation
typedef CGAL::Mesh_triangulation_3<Mesh_domain, CGAL::Default, Concurrency_tag>::type Tr;
typedef CGAL::Mesh_complex_3_in_triangulation_3<
    Tr, Mesh_domain::Corner_index, Mesh_domain::Curve_index> C3t3;
// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;
// To avoid verbose function and named parameters call
using namespace CGAL::parameters;

//Mesh
typedef CGAL::Surface_mesh<K::Point_3> Mesh;

int main(int argc, char*argv[])
{
    const char* fname = (argc > 1) ? argv[1] : "data/fandisk.off";
    std::ifstream input(fname);
    Polyhedron polyhedron;
    input >> polyhedron;
    if (input.fail()) {
        std::cerr << "Error: Cannot read file " << fname << std::endl;
        return EXIT_FAILURE;
    }
    if (!CGAL::is_triangle_mesh(polyhedron)) {
        std::cerr << "Input geometry is not triangulated." << std::endl;
        return EXIT_FAILURE;
    }
    // Create domain
    Mesh_domain domain(polyhedron);
    // Get sharp features
    domain.detect_features();
    // Mesh criteria
    Mesh_criteria criteria(edge_size = 0.025,
        facet_angle = 25, facet_size = 0.05, facet_distance = 0.005,
        cell_radius_edge_ratio = 3, cell_size = 0.05);
    // Mesh generation
    C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria);
    
    // use cgal demo open vtu file can't get desired result
    // Output
    /*std::ofstream file("out.vtu");
    CGAL::output_to_vtu(file, c3t3, CGAL::IO::ASCII);*/

    //use function below can get mesh but doesn't contain segmentation info
    Mesh mesh;
    facets_in_complex_3_to_triangle_mesh(c3t3, mesh);
    std::ofstream output("mesh_smoothed.off");
    output.precision(17);
    output << mesh;


    // Could be replaced by:
    // c3t3.output_to_medit(file);
    return EXIT_SUCCESS;
}

Answer 1

The function sharp_edges_segmentation() should do something similar.