[Libmesh-users] Question regarding Subdivision Implementation in libMesh

[Lee, J. H. <jae...@li...>]

I tried the subdivision example provided in libMesh, and I had some questions about the example that I wasn’t able to find an answer to by myself.

In the example (that follows Cirak’s paper from 2000), I see that there are the following steps before the subdivision mesh gets prepared:

// Quadrisect the mesh triangles a few times to obtain a

// finer mesh. Subdivision surface elements require the

// refinement data to be removed afterward.

MeshRefinement mesh_refinement(mesh);

mesh_refinement.uniformly_refine(3);

MeshTools::Modification::flatten(mesh);


Here, what’s the exact effect of the mesh refinement? I just tried increasing the refinement to 5 or 6, and the solution started deviating quite a lot (by orders of magnitudes) from the analytical solution. I was just wondering if it’s due to just the nature of subdivision or due to the way libMesh works/handles it? Is there a reason 3 is chosen for refinement?

Thank you,
Mike