CGAL users discussion list

["Audette, Michel A." <>]

Dear CGAL users,

I would like to use Mesh_3 to produce a tetrahedral mesh with controlled resolution.

The example in the website where the mesh resolution is controlled is the following...

  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);
  

Please help me interpret these thresholds. I would think that for a triangle, or facet, whose area is related to edge size, whose objective is s (s=0.025 here) it would be given by s^2*sqrt(3)/4, and that the volume of a tetrahedron of edge size s would be given by sqrt(2)/12 *s^3, and yet, in this example, facet and cell sizes appear to be 2*s. Also, could someone also explain the facet_distance concept to me: is there an intuitive relationship with edge size?

I also found that even when I choose this way of invoking make_mesh_3, i.e.: providing it with a surface mesh input which contrains the volumetric meshing,

  C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria);

for some reason, the volumetric meshing remeshes the surface mesh as well, thereby introducing other points that produce small elements near sharp boundaries. Is it possible for me to tell it to leave alone the boundary meshing and only insert nodes within the boundary?

Thanks for your kind support.

Best wishes,

Michel

Michel Audette, Ph.D.

Assistant Professor,

Department of Modeling, Simulation and Visualization Engineering,

Old Dominion University,

Norfolk, VA.