From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Fri, 21 Oct 2016 21:22:25 +0000 (-0500)
Subject: Add a comment.
X-Git-Tag: v8.5.0-rc1~551^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a65af67af063953a8605b3025efd546c93211e5;p=dealii.git

Add a comment.
---

diff --git a/source/grid/grid_generator.cc b/source/grid/grid_generator.cc
index 89fca82001..dad0f4a50a 100644
--- a/source/grid/grid_generator.cc
+++ b/source/grid/grid_generator.cc
@@ -4134,7 +4134,14 @@ namespace GridGenerator
         s.boundary_quads.push_back(quad);
       }
 
-    // use all of this to finally create the extruded 3d triangulation
+    // use all of this to finally create the extruded 3d
+    // triangulation.  it is not necessary to call
+    // GridReordering<3,3>::reorder_cells because the cells we have
+    // constructed above are automatically correctly oriented. this is
+    // because the 2d base mesh is always correctly oriented, and
+    // extruding it automatically yields a correctly oriented 3d mesh,
+    // as discussed in the edge orientation paper mentioned in the
+    // introduction to the GridReordering class.
     result.create_triangulation (points,
                                  cells,
                                  s);