From: bangerth Date: Wed, 27 Feb 2013 04:00:16 +0000 (+0000) Subject: Add one comment. X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f37904f12cb8f90cd52c3f1e44673be38a315dd1;p=dealii-svn.git Add one comment. git-svn-id: https://svn.dealii.org/trunk@28594 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/examples/step-49/step-49.cc b/deal.II/examples/step-49/step-49.cc index a79b4031e7..26fb610365 100644 --- a/deal.II/examples/step-49/step-49.cc +++ b/deal.II/examples/step-49/step-49.cc @@ -197,6 +197,21 @@ void grid_3 () triangulation.set_boundary (1); } +// There is one snag to doing things as shown above: If one moves the nodes on +// the boundary as shown here, one often ends up with cells in the interior +// that are badly distorted since the interior nodes were not moved around. This +// is not that much of a problem in the current case since the mesh did not +// contain any internal nodes when the nodes were moved -- it was the coarse +// mesh and it so happened that all vertices are at the boundary. It's also +// the case that the movement we had here was, compared to the average cell +// size not overly dramatic. Nevertheless, sometimes one does want to move +// vertices by a significant distance, and in that case one needs to move +// internal nodes as well. One way to do that automatically is to call the +// function GridGenerator::laplace_transformation that takes a set of +// transformed nodes and moves all of the other nodes in such a way that the +// resulting mesh has, in some sense, a small distortion. + + // @sect4{grid_4: Demonstrating extrude_triangulation}