Add warning to convert_hypercube_to_simplex_mesh

diff --git a/include/deal.II/grid/grid_generator.h b/include/deal.II/grid/grid_generator.h
index 5ba2a7a074a226760742ad964b6924b1ab8f96ea..d17c7e5d02366cdf055361b58e6efc264875638c 100644 (file)
--- a/include/deal.II/grid/grid_generator.h
+++ b/include/deal.II/grid/grid_generator.h
@@ -1927,6 +1927,15 @@ namespace GridGenerator
    *
    * @param in_tria The triangulation containing hex elements.
    * @param out_tria The converted triangulation containing tet elements.
+   *
+   * @note No manifold objects are copied by this function: you must
+   *   copy existing manifold objects from @p in_tria to @p out_tria, e.g.,
+   *   with the following code:
+   * @code
+   * for (const auto i : in_tria.get_manifold_ids())
+   *   if (i != numbers::flat_manifold_id)
+   *     out_tria.set_manifold(i, in_tria.get_manifold(i));
+   * @endcode
    */
   template <int dim, int spacedim>
   void