diff --git a/Mesh_3/include/CGAL/Mesh_3/Has_features.h b/Mesh_3/include/CGAL/Mesh_3/Has_features.h
index 72423b89fdc..31322e90f58 100644
--- a/Mesh_3/include/CGAL/Mesh_3/Has_features.h
+++ b/Mesh_3/include/CGAL/Mesh_3/Has_features.h
@@ -29,9 +29,9 @@
 #include <CGAL/tags.h>
 
 namespace CGAL {
-
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
+
   // A type has_Has_features to check if type 'Has_features' is a nested
   // type of any class
   BOOST_MPL_HAS_XXX_TRAIT_DEF(Has_features)
@@ -47,8 +47,9 @@ namespace Mesh_3 {
   struct Has_features<Mesh_domain, false> : public CGAL::Tag_false
     // when Mesh_domain does not have the nested type Has_features
   {};
-} // end namespace internal::Mesh_3
+
 } // end namespace internal
+} // end namespace Mesh_3
 } // end namespace CGAL
 
 #endif // CGAL_MESH_3_HAS_FEATURES_H
diff --git a/Mesh_3/include/CGAL/Mesh_3/initialize_triangulation_from_labeled_image.h b/Mesh_3/include/CGAL/Mesh_3/initialize_triangulation_from_labeled_image.h
index 8954a9f6ad3..4ad47fde92c 100644
--- a/Mesh_3/include/CGAL/Mesh_3/initialize_triangulation_from_labeled_image.h
+++ b/Mesh_3/include/CGAL/Mesh_3/initialize_triangulation_from_labeled_image.h
@@ -67,7 +67,7 @@ void init_tr_from_labeled_image_call_init_features(C3T3& c3t3,
                                                    const MeshCriteria& criteria,
                                                    CGAL::Tag_true)
 {
-  CGAL::internal::Mesh_3::init_c3t3_with_features(c3t3,
+  CGAL::Mesh_3::internal::init_c3t3_with_features(c3t3,
                                                   domain,
                                                   criteria);
   std::cout << c3t3.triangulation().number_of_vertices()
@@ -110,7 +110,7 @@ void initialize_triangulation_from_labeled_image(C3T3& c3t3,
   if(protect_features) {
     init_tr_from_labeled_image_call_init_features
       (c3t3, domain, criteria,
-       CGAL::internal::Mesh_3::Has_features<Mesh_domain>());
+       CGAL::Mesh_3::internal::Has_features<Mesh_domain>());
   }
 
   const double max_v = (std::max)((std::max)(image.vx(),
@@ -250,7 +250,7 @@ void initialize_triangulation_from_labeled_image(C3T3& c3t3,
   {
     std::cout << "  not enough points: triangulation.dimension() == "
               << c3t3.triangulation().dimension() << std::endl;
-    CGAL::internal::Mesh_3::init_c3t3(c3t3, domain, criteria, 20);
+    CGAL::Mesh_3::internal::init_c3t3(c3t3, domain, criteria, 20);
     std::cout << "  -> " << tr.number_of_vertices() << " initial points." << std::endl;
   }
 }
diff --git a/Mesh_3/include/CGAL/Mesh_3/polylines_to_protect.h b/Mesh_3/include/CGAL/Mesh_3/polylines_to_protect.h
index f7b76857999..fc904bcc478 100644
--- a/Mesh_3/include/CGAL/Mesh_3/polylines_to_protect.h
+++ b/Mesh_3/include/CGAL/Mesh_3/polylines_to_protect.h
@@ -198,7 +198,7 @@ polylines_to_protect(const CGAL::Image_3& cgal_image,
   const int image_dims[3] = { xdim, ydim, zdim };
 
   Graph graph;
-  internal::Mesh_3::Graph_manipulations<Graph, Point_3> g_manip(graph);
+  Mesh_3::internal::Graph_manipulations<Graph, Point_3> g_manip(graph);
 
   std::size_t
     case4 = 0, // 4 colors
@@ -571,7 +571,7 @@ polylines_to_protect(std::vector<std::vector<P> >& polylines,
   typedef typename std::iterator_traits<PolylineInputIterator>::value_type Polyline;
 
   Graph graph;
-  internal::Mesh_3::Graph_manipulations<Graph, Point_3> g_manip(graph);
+  Mesh_3::internal::Graph_manipulations<Graph, Point_3> g_manip(graph);
 
   for (PolylineInputIterator poly_it = existing_polylines_begin;
        poly_it != existing_polylines_end; ++poly_it)
diff --git a/Mesh_3/include/CGAL/Mesh_3/utilities.h b/Mesh_3/include/CGAL/Mesh_3/utilities.h
index 7b95f621c3d..c0e827d7057 100644
--- a/Mesh_3/include/CGAL/Mesh_3/utilities.h
+++ b/Mesh_3/include/CGAL/Mesh_3/utilities.h
@@ -33,7 +33,6 @@
 #include <sstream>
 
 namespace CGAL {
-
 namespace Mesh_3 {
 namespace internal {
   
@@ -125,8 +124,6 @@ public:
 
 } // end namespace internal  
 } // end namespace Mesh_3
-
-
 } //namespace CGAL
 
 #endif // CGAL_MESH_3_UTILITIES_H
diff --git a/Mesh_3/include/CGAL/Mesh_domain_with_polyline_features_3.h b/Mesh_3/include/CGAL/Mesh_domain_with_polyline_features_3.h
index 5bb495239c3..27fc326fc2d 100644
--- a/Mesh_3/include/CGAL/Mesh_domain_with_polyline_features_3.h
+++ b/Mesh_3/include/CGAL/Mesh_domain_with_polyline_features_3.h
@@ -50,8 +50,8 @@
 namespace CGAL {
 
 /// @cond DEVELOPERS
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template <typename Kernel>
 class Polyline
@@ -509,8 +509,8 @@ struct Display_incidences_to_curves_aux<MDwPF, false> {
                   const Container&) const;
 };
 
-} // end of namespace CGAL::internal::Mesh_3
 } // end of namespace CGAL::internal
+} // end of namespace CGAL::Mesh_3
 /// @endcond
 
 /*!
@@ -843,13 +843,13 @@ private:
 private:
   typedef std::map<Point_3,Corner_index> Corners;
 
-  typedef internal::Mesh_3::Polyline<Gt> Polyline;
+  typedef Mesh_3::internal::Polyline<Gt> Polyline;
   typedef std::map<Curve_index, Polyline> Edges;
   typedef std::map<Curve_index, Surface_patch_index_set > Edges_incidences;
   typedef std::map<Corner_index, std::set<Curve_index> > Corners_tmp_incidences;
   typedef std::map<Corner_index, Surface_patch_index_set > Corners_incidences;
 
-  typedef internal::Mesh_3::Mesh_domain_segment_of_curve_primitive<
+  typedef Mesh_3::internal::Mesh_domain_segment_of_curve_primitive<
     Gt,
     typename Edges::const_iterator> Curves_primitives;
 
@@ -1271,8 +1271,8 @@ get_corner_incident_curves(Corner_index id,
 /// @endcond
 
 /// @cond DEVELOPERS
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template <typename MDwPF_, bool curve_id_is_streamable>
 // here 'curve_id_is_streamable' is true
@@ -1337,7 +1337,8 @@ operator()(std::ostream& os, Point p, typename MDwPF_::Curve_index id,
      << " surface patch(es).\n";
 }
 
-}} // end namespaces internal::Mesh_3:: and internal::
+} // end namespace internal
+} // end namespace Mesh_3
 /// @endcond
 
 /// @cond DEVELOPERS
@@ -1350,7 +1351,7 @@ display_corner_incidences(std::ostream& os, Point_3 p, Corner_index id)
   typedef is_streamable<Surface_patch_index> i_s_spi;
   typedef is_streamable<Curve_index> i_s_csi;
 
-  using namespace internal::Mesh_3;
+  using namespace Mesh_3::internal;
   typedef Display_incidences_to_curves_aux<Mdwpf,i_s_csi::value> D_i_t_c;
   typedef Display_incidences_to_patches_aux<Mdwpf,i_s_spi::value> D_i_t_p;
   D_i_t_c()(os, p, id, corners_tmp_incidences_[id]);
diff --git a/Mesh_3/include/CGAL/Mesh_edge_criteria_3.h b/Mesh_3/include/CGAL/Mesh_edge_criteria_3.h
index 461bee39995..e10c69f12e0 100644
--- a/Mesh_3/include/CGAL/Mesh_edge_criteria_3.h
+++ b/Mesh_3/include/CGAL/Mesh_edge_criteria_3.h
@@ -32,9 +32,8 @@
 #include <boost/type_traits.hpp>
 
 namespace CGAL {
-
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
   // Those two classes are designed to handle dynamic initialization of 
   // Sizing_field type (using named parameters of make_mesh_3 for example)
@@ -91,9 +90,10 @@ namespace Mesh_3 {
   private:
     Sizing_field s_;
   };
-  
-}} // end namespace internal::Mesh_3
-  
+
+} // end namespace internal
+} // end namespace Mesh_3
+
 template < typename Tr >
 class Mesh_edge_criteria_3
 {
@@ -107,7 +107,7 @@ public:
   
   /// Constructors
   Mesh_edge_criteria_3(const FT& value)
-    : p_size_(new internal::Mesh_3::Sizing_field_container<
+    : p_size_(new Mesh_3::internal::Sizing_field_container<
                 Mesh_constant_domain_field_3<Gt,Index> >(value))
   {}
   
@@ -124,7 +124,7 @@ public:
     CGAL_static_assertion((boost::is_same<typename Sizing_field::Index,
                                           Index>::value));
                           
-    p_size_ = new internal::Mesh_3::Sizing_field_container<Sizing_field>(size);
+    p_size_ = new Mesh_3::internal::Sizing_field_container<Sizing_field>(size);
   }
 
   Mesh_edge_criteria_3(const Self& rhs)
@@ -141,7 +141,7 @@ public:
   { return (*p_size_)(p,dim,index); }
   
 private:
-  typedef internal::Mesh_3::Sizing_field_interface<FT,Point_3,Index>
+  typedef Mesh_3::internal::Sizing_field_interface<FT,Point_3,Index>
     Sizing_field_interface;
   
   // A pointer to Sizing_field_interface to handle dynamic wrapping of
diff --git a/Mesh_3/include/CGAL/Mesh_vertex_base_3.h b/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
index c3ee8219589..38ccb42877f 100644
--- a/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
+++ b/Mesh_3/include/CGAL/Mesh_vertex_base_3.h
@@ -281,7 +281,7 @@ operator>>(std::istream &is, Mesh_vertex_base_3<GT,MD,Vb>& v)
   CGAL_assertion(v.in_dimension() >= -1);
   CGAL_assertion(v.in_dimension() < 4);
   typename Vertex::Index index =
-    internal::Mesh_3::Read_mesh_domain_index<MD>()(v.in_dimension(), is);
+    Mesh_3::internal::Read_mesh_domain_index<MD>()(v.in_dimension(), is);
   v.set_index(index);
   return is;
 }
@@ -302,7 +302,7 @@ operator<<(std::ostream &os, const Mesh_vertex_base_3<GT,MD,Vb>& v)
   } else {
     CGAL::write(os, v.in_dimension());
   }
-  internal::Mesh_3::Write_mesh_domain_index<MD>()(os, 
+  Mesh_3::internal::Write_mesh_domain_index<MD>()(os,
                                                   v.in_dimension(),
                                                   v.index());
   return os;
diff --git a/Mesh_3/include/CGAL/Polyhedral_complex_mesh_domain_3.h b/Mesh_3/include/CGAL/Polyhedral_complex_mesh_domain_3.h
index bbc75e5d332..82e2aeeec68 100644
--- a/Mesh_3/include/CGAL/Polyhedral_complex_mesh_domain_3.h
+++ b/Mesh_3/include/CGAL/Polyhedral_complex_mesh_domain_3.h
@@ -57,8 +57,8 @@
 
 namespace CGAL {
 /// @cond DEVELOPERS
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template <typename Graph>
 void dump_graph_edges(std::ostream& out, const Graph& g)
@@ -202,8 +202,8 @@ struct Extract_polyline_with_context_visitor
 };
 
 
-} // end CGAL::internal::Mesh_3
-} // end CGAL::internal
+} // end namespace internal
+} // end namespace Mesh_3
 
 /// @endcond
 
@@ -889,7 +889,7 @@ detect_features(FT angle_in_degree,
   BOOST_FOREACH(Polyhedron_type& p, poly)
   {
     initialize_ts(p);
-    using internal::Mesh_3::Get_face_index_pmap;
+    using Mesh_3::internal::Get_face_index_pmap;
     Get_face_index_pmap<Polyhedron_type> get_face_index_pmap(p);
 #ifdef CGAL_MESH_3_VERBOSE
     std::size_t poly_id = &p-&poly[0];
@@ -911,7 +911,7 @@ detect_features(FT angle_in_degree,
       .vertex_incident_patches_map(vip_map)
       .vertex_feature_degree_map(vertex_feature_degree_map));
 
-    internal::Mesh_3::Is_featured_edge<Polyhedron_type> is_featured_edge(p);
+    Mesh_3::internal::Is_featured_edge<Polyhedron_type> is_featured_edge(p);
 
     add_featured_edges_to_graph(p, is_featured_edge, g_copy, p2vmap);
   }
@@ -1034,12 +1034,12 @@ add_features_from_split_graph_into_polylines(Featured_edges_copy_graph& g_copy)
 {
   std::vector<Polyline_with_context> polylines;
 
-  internal::Mesh_3::Extract_polyline_with_context_visitor<
+  Mesh_3::internal::Extract_polyline_with_context_visitor<
     Polyhedral_complex_mesh_domain_3,
     Polyline_with_context,
     Featured_edges_copy_graph
     > visitor(g_copy, polylines);
-  internal::Mesh_3::Angle_tester<GT_> angle_tester;
+  Mesh_3::internal::Angle_tester<GT_> angle_tester;
   split_graph_into_polylines(g_copy, visitor, angle_tester);
 
   this->add_features_with_context(polylines.begin(),
@@ -1120,7 +1120,7 @@ add_featured_edges_to_graph(const Polyhedron_type& p,
 
 #if CGAL_MESH_3_PROTECTION_DEBUG > 1
   {// DEBUG
-    internal::Mesh_3::dump_graph_edges("edges-graph.polylines.txt", g_copy);
+    Mesh_3::internal::dump_graph_edges("edges-graph.polylines.txt", g_copy);
   }
 #endif
 }
diff --git a/Mesh_3/include/CGAL/Polyhedral_mesh_domain_3.h b/Mesh_3/include/CGAL/Polyhedral_mesh_domain_3.h
index 8e90cb7fa87..b95f27cd997 100644
--- a/Mesh_3/include/CGAL/Polyhedral_mesh_domain_3.h
+++ b/Mesh_3/include/CGAL/Polyhedral_mesh_domain_3.h
@@ -127,11 +127,10 @@ struct IGT_generator<Gt,CGAL::Tag_false>
 };
 
 }  // end namespace details
-
 }  // end namespace Mesh_3
 
-
-namespace internal { namespace Mesh_3 {
+namespace Mesh_3 {
+namespace internal {
 
 template <typename Polyhedron_type,
           bool = boost::graph_has_property<Polyhedron_type,
@@ -168,8 +167,8 @@ private:
   Map face_ids;
 };
 
-} // end namespace Mesh_3
 } // end namespace internal
+} // end namespace Mesh_3
 
 /**
  * @class Polyhedral_mesh_domain_3
diff --git a/Mesh_3/include/CGAL/Polyhedral_mesh_domain_with_features_3.h b/Mesh_3/include/CGAL/Polyhedral_mesh_domain_with_features_3.h
index 72ed02ffe8b..97e11339411 100644
--- a/Mesh_3/include/CGAL/Polyhedral_mesh_domain_with_features_3.h
+++ b/Mesh_3/include/CGAL/Polyhedral_mesh_domain_with_features_3.h
@@ -60,9 +60,8 @@
 
 
 namespace CGAL {
-
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template <typename Kernel>
 struct Angle_tester
@@ -184,8 +183,8 @@ struct Extract_polyline_with_context_visitor
 };
 
 
-} // end CGAL::internal::Mesh_3
-} // end CGAL::internal
+} // end namespace internal
+} // end namespace Mesh_3
 
 /**
  * @class Polyhedral_mesh_domain_with_features_3
@@ -463,7 +462,7 @@ detect_features(FT angle_in_degree, std::vector<Polyhedron>& poly)
     typedef typename boost::property_map<Polyhedron,CGAL::vertex_incident_patches_t<P_id> >::type VIPMap;
     typedef typename boost::property_map<Polyhedron, CGAL::edge_is_feature_t>::type EIFMap;
 
-    using internal::Mesh_3::Get_face_index_pmap;
+    using Mesh_3::internal::Get_face_index_pmap;
     Get_face_index_pmap<Polyhedron> get_face_index_pmap(p);
 
     PIDMap pid_map = get(face_patch_id_t<Tag_>(), p);
@@ -478,7 +477,7 @@ detect_features(FT angle_in_degree, std::vector<Polyhedron>& poly)
       .face_index_map(get_face_index_pmap(p))
       .vertex_incident_patches_map(vip_map));
 
-    internal::Mesh_3::Is_featured_edge<Polyhedron> is_featured_edge(p);
+    Mesh_3::internal::Is_featured_edge<Polyhedron> is_featured_edge(p);
 
     add_featured_edges_to_graph(p, is_featured_edge, g_copy, p2vmap);
   }
@@ -508,12 +507,12 @@ add_features_from_split_graph_into_polylines(Featured_edges_copy_graph& g_copy)
 {
   std::vector<Polyline_with_context> polylines;
 
-  internal::Mesh_3::Extract_polyline_with_context_visitor<
+  Mesh_3::internal::Extract_polyline_with_context_visitor<
     Polyhedral_mesh_domain_with_features_3,
     Polyline_with_context,
     Featured_edges_copy_graph
     > visitor(g_copy, polylines);
-  internal::Mesh_3::Angle_tester<GT_> angle_tester;
+  Mesh_3::internal::Angle_tester<GT_> angle_tester;
   split_graph_into_polylines(g_copy, visitor, angle_tester);
 
   this->add_features_with_context(polylines.begin(),
diff --git a/Mesh_3/include/CGAL/internal/Mesh_3/Graph_manipulations.h b/Mesh_3/include/CGAL/internal/Mesh_3/Graph_manipulations.h
index 0e4dcf3b2e1..ea8c6e4a91e 100644
--- a/Mesh_3/include/CGAL/internal/Mesh_3/Graph_manipulations.h
+++ b/Mesh_3/include/CGAL/internal/Mesh_3/Graph_manipulations.h
@@ -33,8 +33,8 @@
 #include <map>
 
 namespace CGAL {
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template <typename Graph, typename Point_3>
 struct Graph_manipulations
@@ -116,8 +116,8 @@ struct Graph_manipulations
   }
 }; // struct template Graph_manipulations
 
-} // namespace Mesh_3
 } // namespace internal
+} // namespace Mesh_3
 } // namespace CGAL
 
 #endif //CGAL_INTERNAL_MESH_3_INTERNAL_GRAPH_MANIPULATIONS
diff --git a/Mesh_3/include/CGAL/internal/Mesh_3/check_weights.h b/Mesh_3/include/CGAL/internal/Mesh_3/check_weights.h
index 8aa8b602ec0..b9b0ad67dec 100644
--- a/Mesh_3/include/CGAL/internal/Mesh_3/check_weights.h
+++ b/Mesh_3/include/CGAL/internal/Mesh_3/check_weights.h
@@ -35,8 +35,8 @@
 #include <boost/type_traits/is_same.hpp>
 
 namespace CGAL {
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 
 template<typename Triangulation, typename MeshDomain>
@@ -68,9 +68,9 @@ bool has_non_protecting_weights(const Triangulation& tr,
 }
 
 
-}//end namespace Mesh_3
-}//end namespace internal
-}//end namespace CGAL
+} // end namespace internal
+} // end namespace Mesh_3
+} // end namespace CGAL
 
 #endif //CGAL_INTERNAL_MESH_3_CHECK_WEIGHTS_H
 
diff --git a/Mesh_3/include/CGAL/internal/Mesh_3/get_index.h b/Mesh_3/include/CGAL/internal/Mesh_3/get_index.h
index db9b6cf8e05..5290ebf429e 100644
--- a/Mesh_3/include/CGAL/internal/Mesh_3/get_index.h
+++ b/Mesh_3/include/CGAL/internal/Mesh_3/get_index.h
@@ -35,10 +35,10 @@
 #include <CGAL/IO/io.h>
 
 namespace CGAL {
-namespace internal {
 namespace Mesh_3 {
-  
-  
+namespace internal {
+
+
 template <typename T, typename Boost_variant>
 const T& get_index(const Boost_variant& x,
                    typename boost::disable_if<boost::is_same<T, Boost_variant> >::type * = 0)
@@ -167,8 +167,8 @@ struct Write_mesh_domain_index<Mesh_domain, false> {
 
 
 
-}
-}
-}
+} // end namespace internal
+} // end namespace Mesh_3
+} // end namespace CGAL
 
 #endif
diff --git a/Mesh_3/include/CGAL/lloyd_optimize_mesh_3.h b/Mesh_3/include/CGAL/lloyd_optimize_mesh_3.h
index 0c059121831..187c4058571 100644
--- a/Mesh_3/include/CGAL/lloyd_optimize_mesh_3.h
+++ b/Mesh_3/include/CGAL/lloyd_optimize_mesh_3.h
@@ -76,7 +76,7 @@ lloyd_optimize_mesh_3_impl(C3T3& c3t3,
                            , const bool do_freeze)
 {
   CGAL_precondition(
-    !internal::Mesh_3::has_non_protecting_weights(c3t3.triangulation(), domain));
+    !Mesh_3::internal::has_non_protecting_weights(c3t3.triangulation(), domain));
 
   typedef typename C3T3::Triangulation  Tr;
   
diff --git a/Mesh_3/include/CGAL/make_mesh_3.h b/Mesh_3/include/CGAL/make_mesh_3.h
index 1699fcd63e6..f792ef2718e 100644
--- a/Mesh_3/include/CGAL/make_mesh_3.h
+++ b/Mesh_3/include/CGAL/make_mesh_3.h
@@ -110,7 +110,7 @@ namespace parameters {
   {
     typedef typename internal::Domain_features_generator<
       MeshDomain,
-      CGAL::internal::Mesh_3::has_Has_features<MeshDomain>::value > Generator;
+      CGAL::Mesh_3::internal::has_Has_features<MeshDomain>::value > Generator;
 
     return Generator()();
   }
@@ -134,8 +134,8 @@ CGAL_PRAGMA_DIAG_POP
 // -----------------------------------
 // Initialize c3t3 stuff
 // -----------------------------------
-namespace internal {
 namespace Mesh_3 {
+namespace internal {
 
 template < typename C3T3, typename MeshDomain, typename MeshCriteria >
 void
@@ -315,7 +315,8 @@ struct C3t3_initializer < C3T3, MD, MC, true, CGAL::Tag_false >
   }
 };
 
-}} // end namespace internal::Mesh_3
+} // end namespace internal
+} // end namespace Mesh_3
 
 
 // -----------------------------------
@@ -456,11 +457,11 @@ void make_mesh_3_impl(C3T3& c3t3,
 #endif
 
   // Initialize c3t3
-  internal::Mesh_3::C3t3_initializer<
+  Mesh_3::internal::C3t3_initializer<
     C3T3,
     MeshDomain,
     MeshCriteria,
-    internal::Mesh_3::has_Has_features<MeshDomain>::value > () (c3t3,
+    Mesh_3::internal::has_Has_features<MeshDomain>::value > () (c3t3,
             domain,
             criteria,
             with_features,
diff --git a/Mesh_3/include/CGAL/odt_optimize_mesh_3.h b/Mesh_3/include/CGAL/odt_optimize_mesh_3.h
index 76a3d14bb8e..d19d6492588 100644
--- a/Mesh_3/include/CGAL/odt_optimize_mesh_3.h
+++ b/Mesh_3/include/CGAL/odt_optimize_mesh_3.h
@@ -76,7 +76,7 @@ odt_optimize_mesh_3_impl(C3T3& c3t3,
                          const bool do_freeze )
 {
   CGAL_precondition(
-    !internal::Mesh_3::has_non_protecting_weights(c3t3.triangulation(), domain));
+    !Mesh_3::internal::has_non_protecting_weights(c3t3.triangulation(), domain));
 
   typedef typename C3T3::Triangulation  Tr;
   
diff --git a/Mesh_3/include/CGAL/perturb_mesh_3.h b/Mesh_3/include/CGAL/perturb_mesh_3.h
index 5190ecf56bf..64795d7e920 100644
--- a/Mesh_3/include/CGAL/perturb_mesh_3.h
+++ b/Mesh_3/include/CGAL/perturb_mesh_3.h
@@ -107,7 +107,7 @@ perturb_mesh_3_impl(C3T3& c3t3,
                     const PPerturbationVector& perturbation_vector)
 {
   CGAL_precondition(
-    !internal::Mesh_3::has_non_protecting_weights(c3t3.triangulation(), domain));
+    !Mesh_3::internal::has_non_protecting_weights(c3t3.triangulation(), domain));
 
   typedef MeshDomain Md;
   typedef SliverCriterion Sc;
diff --git a/Mesh_3/test/Mesh_3/test_meshing_polyhedral_complex.cpp b/Mesh_3/test/Mesh_3/test_meshing_polyhedral_complex.cpp
index b4946e6c08a..d058ba21bbe 100644
--- a/Mesh_3/test/Mesh_3/test_meshing_polyhedral_complex.cpp
+++ b/Mesh_3/test/Mesh_3/test_meshing_polyhedral_complex.cpp
@@ -101,7 +101,7 @@ struct Polyhedral_complex_tester : public Tester<K>
     // Mesh generation
     C3t3 c3t3;
 
-    CGAL::internal::Mesh_3::init_c3t3_with_features(c3t3, domain, criteria,
+    CGAL::Mesh_3::internal::init_c3t3_with_features(c3t3, domain, criteria,
       true /*nonlinear_growth_of_balls*/);
     domain.add_vertices_to_c3t3_on_patch_without_feature_edges(c3t3);
 
diff --git a/Mesh_3/test/Mesh_3/test_meshing_polylines_only.cpp b/Mesh_3/test/Mesh_3/test_meshing_polylines_only.cpp
index e3cbc677b06..d2b056095f1 100644
--- a/Mesh_3/test/Mesh_3/test_meshing_polylines_only.cpp
+++ b/Mesh_3/test/Mesh_3/test_meshing_polylines_only.cpp
@@ -82,15 +82,12 @@ int main(int argc, char** argv)
   // Mesh criteria
   Mesh_criteria criteria(edge_size = 0.1);
   typedef Mesh_criteria::Edge_criteria Edge_criteria;
-  typedef CGAL::internal::Mesh_3::Edge_criteria_sizing_field_wrapper<Edge_criteria> Sizing_field;
-  CGAL::Mesh_3::Protect_edges_sizing_field<C3t3,
-					   Mesh_domain,
-					   Sizing_field>
-    protect_edges(c3t3, domain, Sizing_field(criteria.edge_criteria_object()),
-		  0.01);
+  typedef CGAL::Mesh_3::internal::Edge_criteria_sizing_field_wrapper<Edge_criteria> Sizing_field;
+  CGAL::Mesh_3::Protect_edges_sizing_field<C3t3, Mesh_domain, Sizing_field>
+    protect_edges(c3t3, domain, Sizing_field(criteria.edge_criteria_object()), 0.01);
   protect_edges(true);
 
-  // CGAL::internal::Mesh_3::init_c3t3_with_features(c3t3, domain, criteria);
+  // CGAL::Mesh_3::internal::init_c3t3_with_features(c3t3, domain, criteria);
 
   // Output
   std::ofstream medit_file("out-mesh-polylines.mesh");
diff --git a/Periodic_3_mesh_3/include/CGAL/make_periodic_3_mesh_3.h b/Periodic_3_mesh_3/include/CGAL/make_periodic_3_mesh_3.h
index 0872dc50632..0bacffb7f51 100644
--- a/Periodic_3_mesh_3/include/CGAL/make_periodic_3_mesh_3.h
+++ b/Periodic_3_mesh_3/include/CGAL/make_periodic_3_mesh_3.h
@@ -37,9 +37,8 @@
 #include <iterator>
 
 namespace CGAL {
-
-namespace internal {
 namespace Periodic_3_mesh_3 {
+namespace internal {
 
 template<typename C3T3>
 void give_dummy_points_artificial_index(C3T3& c3t3)
@@ -56,21 +55,36 @@ void give_dummy_points_artificial_index(C3T3& c3t3)
   }
 }
 
+template <typename C3T3, typename MeshDomain, typename MeshCriteria>
+void init_c3t3_with_features(C3T3& c3t3,
+                             const MeshDomain& domain,
+                             const MeshCriteria& criteria,
+                             bool nonlinear = false)
+{
+  typedef typename MeshCriteria::Edge_criteria                                Edge_criteria;
+  typedef Mesh_3::internal::Edge_criteria_sizing_field_wrapper<Edge_criteria> Sizing_field;
+
+  CGAL::Periodic_3_mesh_3::Protect_edges_sizing_field<C3T3, MeshDomain, Sizing_field>
+    protect_edges(c3t3, domain, Sizing_field(criteria.edge_criteria_object()));
+  protect_edges.set_nonlinear_growth_of_balls(nonlinear);
+
+  protect_edges(true);
+}
+
 // C3t3_initializer: initialize c3t3
 template < typename C3T3,
            typename MeshDomain,
            typename MeshCriteria,
            bool MeshDomainHasHasFeatures,
            typename HasFeatures = int>
-class C3t3_initializer
-  : public CGAL::internal::Mesh_3::C3t3_initializer<
+struct C3t3_initializer_base
+  : public CGAL::Mesh_3::internal::C3t3_initializer<
       C3T3, MeshDomain, MeshCriteria, MeshDomainHasHasFeatures, HasFeatures>
 {
-  typedef CGAL::internal::Mesh_3::C3t3_initializer<
+  typedef CGAL::Mesh_3::internal::C3t3_initializer<
             C3T3, MeshDomain, MeshCriteria,
             MeshDomainHasHasFeatures, HasFeatures>              Base;
 
-public:
   void operator()(C3T3& c3t3,
                   const MeshDomain& domain,
                   const MeshCriteria& criteria,
@@ -80,7 +94,6 @@ public:
   {
     c3t3.triangulation().set_domain(domain.periodic_bounding_box());
     c3t3.triangulation().insert_dummy_points();
-
     give_dummy_points_artificial_index(c3t3);
 
     // Call the basic initialization from c3t3, which handles features and
@@ -92,6 +105,7 @@ public:
 
 } // namespace Periodic_3_mesh_3
 } // namespace internal
+} // namespace Periodic_3_mesh_3
 
 // -----------------------------------
 // make_periodic_3_mesh_3 stuff
@@ -225,9 +239,9 @@ void make_periodic_3_mesh_3_impl(C3T3& c3t3,
                                    manifold_options = parameters::internal::Manifold_options())
 {
   // Initialize c3t3
-  internal::Periodic_3_mesh_3::C3t3_initializer<
+  Periodic_3_mesh_3::internal::C3t3_initializer<
     C3T3, MeshDomain, MeshCriteria,
-    internal::Mesh_3::has_Has_features<MeshDomain>::value>()(c3t3,
+    Mesh_3::internal::has_Has_features<MeshDomain>::value>()(c3t3,
                                                              domain,
                                                              criteria,
                                                              with_features,