CGAL::perturb_mesh_3

Definition

The function perturb_mesh_3 is a mesh optimizer that improves the quality of a Delaunay mesh by changing the mesh vertices positions.

The perturber tries to improve the dihedral angles of the worst cells in the mesh degree by degree: the step number n is considered as successful if after this step the worst tetrahedron of the mesh has a minimal dihedral angle larger than n degrees. The perturber exits if this is not the case.

#include <CGAL/perturb_mesh_3.h>

Precondition

Parameters

Parameter C3T3 is required to be a model of the concept MeshComplex_3InTriangulation_3. The argument c3t3, passed by reference, provides the initial mesh and is modified by the algorithm to represent the final optimized mesh.

Parameter MeshDomain_3 is required to be a model of the concept MeshDomain_3. The argument domain must be the MeshDomain_3 object used to create the c3t3 parameter.

The function has two optional parameters which are named parameters (we use the Boost.Parameter library). Therefore, when calling the function, the parameters can be provided in any order provided that the names of the parameters are used (see example at the bottom of this page).

• Parameter time_limit whose name is parameters::time_limit, is used to set up, in seconds, a CPU time limit after which the optimization process is stopped. This time is measured using CGAL::Timer. The default value is 0 and means that there is no time limit.
• Parameter sliver_bound, whose name is parameters::sliver_bound, is designed to give, in degree, a targeted lower bound on dihedral angles of mesh cells. The function perturb_mesh_3 runs as long as steps are successful and step number sliver_bound (after which the worst tetrahedron in the mesh has a smallest angle larger than sliver_bound degrees) has not been reached. The default value is 0 and means that there is no targeted bound: the perturber then runs as long as steps are successful.

Return Values

• BOUND_REACHED when the targeted bound for the smallest dihedral angle in the mesh is reached.
• TIME_LIMIT_REACHED when the time limit is reached.
• CANT_IMPROVE_ANYMORE when the perturbation process stops because the last step is unsuccessful.

Example

// Perturb until every dihedral angle of the mesh is >= 10 degrees
// No time bound is set
perturb_mesh_3(c3t3, domain, parameters::sliver_bound=10);

See Also

CGAL::Mesh_optimization_return_code
CGAL::make_mesh_3
CGAL::refine_mesh_3
CGAL::exude_mesh_3
CGAL::lloyd_optimize_mesh_3
CGAL::odt_optimize_mesh_3