diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/CMakeLists.txt b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/CMakeLists.txt
index f81b552b293..729bdeefd51 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/CMakeLists.txt
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/CMakeLists.txt
@@ -16,10 +16,6 @@ qt5_wrap_ui( mesh_simplificationUI_FILES  Mesh_simplification_dialog.ui)
 polyhedron_demo_plugin(mesh_simplification_plugin Mesh_simplification_plugin ${mesh_simplificationUI_FILES})
 target_link_libraries(mesh_simplification_plugin scene_polyhedron_item scene_polyhedron_selection_item)
 
-polyhedron_demo_plugin(mesh_simplification_sm_plugin Mesh_simplification_plugin ${mesh_simplificationUI_FILES})
-target_link_libraries(mesh_simplification_sm_plugin scene_surface_mesh_item scene_surface_mesh_selection_item)
-target_compile_definitions(mesh_simplification_sm_plugin PUBLIC "-DUSE_SURFACE_MESH" )
-
 
 qt5_wrap_ui( remeshingUI_FILES  Remeshing_dialog.ui)
 polyhedron_demo_plugin(remeshing_plugin Remeshing_plugin Remeshing_plugin_cgal_code.cpp Mesher_base.cpp ${remeshingUI_FILES})
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Mesh_simplification_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Mesh_simplification_plugin.cpp
index ce34590f0ad..a1bac43805c 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Mesh_simplification_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Mesh_simplification_plugin.cpp
@@ -1,13 +1,8 @@
 #include <CGAL/Three/Polyhedron_demo_plugin_interface.h>
 
-#ifdef USE_SURFACE_MESH
-#include "Scene_surface_mesh_item.h"
-#else
 #include "Scene_polyhedron_item.h"
-#include "Polyhedron_type.h"
-#endif
-
 #include "Scene_polyhedron_selection_item.h"
+#include "Polyhedron_type.h"
 
 #include <QApplication>
 #include <QMainWindow>
@@ -15,6 +10,7 @@
 #include <QTime>
 #include <QAction>
 
+#include <CGAL/Surface_mesh_simplification/HalfedgeGraph_Polyhedron_3.h>
 #include <CGAL/Surface_mesh_simplification/edge_collapse.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_stop_predicate.h>
@@ -23,18 +19,10 @@
 
 #include "ui_Mesh_simplification_dialog.h"
 
-#ifdef USE_SURFACE_MESH
-typedef Scene_surface_mesh_item Scene_face_graph_item;
-#else
-typedef Scene_polyhedron_item Scene_face_graph_item;
-#endif
-
-typedef Scene_face_graph_item::FaceGraph Face_graph;
-
 class Custom_stop_predicate
 {
   bool m_and;
-  CGAL::Surface_mesh_simplification::Count_stop_predicate<Face_graph> m_count_stop;
+  CGAL::Surface_mesh_simplification::Count_stop_predicate<Polyhedron> m_count_stop;
   CGAL::Surface_mesh_simplification::Edge_length_stop_predicate<double> m_length_stop;
   
 public:
@@ -92,7 +80,7 @@ public:
 
   }
   bool applicable(QAction*) const { 
-    return qobject_cast<Scene_face_graph_item*>(scene->item(scene->mainSelectionIndex()))
+    return qobject_cast<Scene_polyhedron_item*>(scene->item(scene->mainSelectionIndex()))
       || qobject_cast<Scene_polyhedron_selection_item*>(scene->item(scene->mainSelectionIndex()));
   }
 public Q_SLOTS:
@@ -108,15 +96,15 @@ void Polyhedron_demo_mesh_simplification_plugin::on_actionSimplify_triggered()
 {
   const CGAL::Three::Scene_interface::Item_id index = scene->mainSelectionIndex();
   
-  Scene_face_graph_item* poly_item = 
-    qobject_cast<Scene_face_graph_item*>(scene->item(index));
+  Scene_polyhedron_item* poly_item = 
+    qobject_cast<Scene_polyhedron_item*>(scene->item(index));
 
   Scene_polyhedron_selection_item* selection_item =
     qobject_cast<Scene_polyhedron_selection_item*>(scene->item(index));
 
   if (poly_item || selection_item)
   {
-    Face_graph& pmesh = (poly_item != NULL)
+    Polyhedron& pmesh = (poly_item != NULL)
       ? *poly_item->polyhedron()
       : *selection_item->polyhedron();
 
@@ -137,8 +125,8 @@ void Polyhedron_demo_mesh_simplification_plugin::on_actionSimplify_triggered()
                                      + (bbox.ymax()-bbox.ymin())*(bbox.ymax()-bbox.ymin()) +
                                      (bbox.zmax()-bbox.zmin())*(bbox.zmax()-bbox.zmin()));
     
-    ui.m_nb_edges->setValue ((int)(num_halfedges(pmesh) / 4));
-    ui.m_nb_edges->setMaximum ((int)(num_halfedges(pmesh)));
+    ui.m_nb_edges->setValue ((int)(pmesh.size_of_halfedges () / 4));
+    ui.m_nb_edges->setMaximum ((int)(pmesh.size_of_halfedges ()));
     ui.m_edge_length->setValue (diago_length * 0.05);
 
     // check user cancellation
@@ -165,7 +153,7 @@ void Polyhedron_demo_mesh_simplification_plugin::on_actionSimplify_triggered()
       {
         CGAL::Surface_mesh_simplification::Constrained_placement
           <CGAL::Surface_mesh_simplification::LindstromTurk_placement
-           <Face_graph>,
+           <Polyhedron>,
            Scene_polyhedron_selection_item::Is_constrained_map
            <Scene_polyhedron_selection_item::Selection_set_edge> >
           placement (selection_item->constrained_edges_pmap());
@@ -183,7 +171,7 @@ void Polyhedron_demo_mesh_simplification_plugin::on_actionSimplify_triggered()
       }
     
     std::cout << "ok (" << time.elapsed() << " ms, " 
-              << num_edges(pmesh) << " edges)" << std::endl;
+      << pmesh.size_of_halfedges() / 2 << " edges)" << std::endl;
 
     // update scene
     if (poly_item != NULL)