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git-svn-id: https://svn.dealii.org/trunk@22785 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/grid/grid_tools.h b/deal.II/include/deal.II/grid/grid_tools.h
index 68ea24e2ff87afc22c68584ed8280e708a9ea8e0..ea4db5ce47ff83f8901664d31c5afa92985ec93d 100644 (file)
--- a/deal.II/include/deal.II/grid/grid_tools.h
+++ b/deal.II/include/deal.II/grid/grid_tools.h
@@ -809,6 +809,29 @@ class GridTools
                                      * It also builds a mapping linking the
                                      * cells on the surface mesh to the
                                      * corresponding faces on the volume one.
+                                     *
+                                     * @note The function builds the surface
+                                     * mesh by creating a coarse mesh from
+                                     * the selected faces of the coarse cells
+                                     * of the volume mesh. It copies the
+                                     * boundary indicators of these faces to
+                                     * the cells of the coarse surface
+                                     * mesh. The surface mesh is then refined
+                                     * in the same way as the faces of the
+                                     * volume mesh are. In order to ensure
+                                     * that the surface mesh has the same
+                                     * vertices as the volume mesh, it is
+                                     * therefore important that you assign
+                                     * appropriate boundary objects through
+                                     * Triangulation::set_boundary to the
+                                     * surface mesh object before calling
+                                     * this function. If you don't, the
+                                     * refinement will happen under the
+                                     * assumption that all faces are straight
+                                     * (i.e using the StraightBoundary class)
+                                     * rather than any curved boundary object
+                                     * you may want to use to determine the
+                                     * location of new vertices.
                                      */
     template <int dim, int spacedim>
     static void