diff --git a/apps/sample/sample.pro b/apps/sample/sample.pro
index ab414706..07e6859b 100644
--- a/apps/sample/sample.pro
+++ b/apps/sample/sample.pro
@@ -1,9 +1,11 @@
 
 TEMPLATE      = subdirs
 SUBDIRS       = trimesh_base  \
-                trimesh_topology\
+                trimesh_topology \
                 trimesh_smooth \
                 trimesh_curvature \
+                trimesh_normal \
+                trimesh_inertia \
                 trimesh_refine \
                 trimesh_clustering \
                 trimesh_isosurface \
diff --git a/apps/sample/trimesh_attribute/trimesh_attribute.cpp b/apps/sample/trimesh_attribute/trimesh_attribute.cpp
index b4507443..a846fe7e 100644
--- a/apps/sample/trimesh_attribute/trimesh_attribute.cpp
+++ b/apps/sample/trimesh_attribute/trimesh_attribute.cpp
@@ -20,6 +20,15 @@
 * for more details.                                                         *
 *                                                                           *
 ****************************************************************************/
+/*! \file trimesh_attribute.cpp
+\ingroup code_sample
+
+\brief the minimal example of using the attributes
+
+Attributes are a simple mechanism to associate user-defined 'attributes' to the simplicies and to the mesh.
+\ref attributes for more Details
+
+*/
 
 #include<vcg/complex/complex.h>
 
@@ -59,13 +68,13 @@ int main()
    ih[&*vi]= 1.0f;  //                or a pointer to it
    ih[i]   = 1.0f;  //                or an integer index
   }
-    
-  // Once created with AddPerVertexAttribute, an handle to the attribute can be obtained as follows
-  MyMesh::PerVertexAttributeHandle<float> rh = vcg::tri::Allocator<MyMesh>::GetPerVertexAttribute<float>(m,"Radiosity");
 
   // you can query if an attribute is present or not
   bool hasRadiosity = vcg::tri::HasPerVertexAttribute(m,"Radiosity");
 
+  // Once created with AddPerVertexAttribute, an handle to the attribute can be obtained as follows
+  MyMesh::PerVertexAttributeHandle<float> rh = vcg::tri::Allocator<MyMesh>::GetPerVertexAttribute<float>(m,"Radiosity");
+
   // you can delete an attibute by name
   vcg::tri::Allocator<MyMesh>::DeletePerVertexAttribute(m,"Radiosity");
 
diff --git a/apps/sample/trimesh_base/trimesh_base.cpp b/apps/sample/trimesh_base/trimesh_base.cpp
index 13f120a8..756390f7 100644
--- a/apps/sample/trimesh_base/trimesh_base.cpp
+++ b/apps/sample/trimesh_base/trimesh_base.cpp
@@ -21,9 +21,10 @@
 *                                                                           *
 ****************************************************************************/
 /*! \file trimesh_base.cpp
-\brief the minimal example of using the lib
 \ingroup code_sample
 
+\brief the minimal example of using the lib
+
 This file contain a minimal example of the library
 
 */
diff --git a/apps/sample/trimesh_curvature/trimesh_curvature.cpp b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
index 2485ea84..15b1cb73 100644
--- a/apps/sample/trimesh_curvature/trimesh_curvature.cpp
+++ b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
@@ -60,6 +60,11 @@ int main( int argc, char **argv )
 
   tri::UpdateTopology<MyMesh>::FaceFace(m);
   tri::UpdateCurvature<MyMesh>::PerVertex(m);
+  tri::UpdateCurvature<MyMesh>::MeanAndGaussian(m);
+  tri::UpdateCurvature<MyMesh>::PrincipalDirections(m);
+  tri::UpdateCurvature<MyMesh>::PrincipalDirectionsNormalCycle(m);
+  tri::UpdateCurvature<MyMesh>::PrincipalDirectionsPCA(m,m.bbox.Diag()/100);
+
   tri::UpdateNormal<MyMesh>::PerVertexNormalized(m);
   printf("Input mesh  vn:%i fn:%i\n",m.VN(),m.FN());
   printf( "Mesh has %i vert and %i faces\n", m.VN(), m.FN() );
diff --git a/apps/sample/trimesh_smooth/trimesh_smooth.cpp b/apps/sample/trimesh_smooth/trimesh_smooth.cpp
index c1b0a98d..187c038e 100644
--- a/apps/sample/trimesh_smooth/trimesh_smooth.cpp
+++ b/apps/sample/trimesh_smooth/trimesh_smooth.cpp
@@ -1,3 +1,33 @@
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004-2012                                           \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* This program is free software; you can redistribute it and/or modify      *
+* it under the terms of the GNU General Public License as published by      *
+* the Free Software Foundation; either version 2 of the License, or         *
+* (at your option) any later version.                                       *
+*                                                                           *
+* This program is distributed in the hope that it will be useful,           *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of            *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
+* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/*! \file trimesh_smooth.cpp
+\ingroup code_sample
+
+\brief the minimal example of using the lib
+
+This file contain a minimal example of the library
+
+*/
 
 #include<vcg/complex/complex.h>
 #include <vcg/complex/algorithms/update/topology.h>
@@ -17,9 +47,8 @@ using namespace std;
 
 class MyFace;
 class MyVertex;
-struct MyUsedTypes : public UsedTypes<	Use<MyVertex>::AsVertexType,
-																				Use<MyFace>::AsFaceType>{};
 
+struct MyUsedTypes : public UsedTypes<	Use<MyVertex>::AsVertexType, Use<MyFace>::AsFaceType>{};
 class MyVertex  : public Vertex< MyUsedTypes, vertex::VFAdj, vertex::Coord3f, vertex::Normal3f, vertex::BitFlags  >{};
 class MyFace    : public Face  < MyUsedTypes, face::VFAdj, face::Normal3f, face::VertexRef, face::BitFlags > {};
 class MyMesh    : public vcg::tri::TriMesh<vector<MyVertex>, vector<MyFace> > {};
@@ -32,6 +61,8 @@ int main(int argc,char ** argv)
     return 0;
   }
 
+  int Step= atoi(argv[2]);
+
   MyMesh m;
 
   //open a mesh
@@ -45,7 +76,6 @@ int main(int argc,char ** argv)
   int dup = tri::Clean<MyMesh>::RemoveDuplicateVertex(m);
   int unref = tri::Clean<MyMesh>::RemoveUnreferencedVertex(m);
   printf("Removed %i duplicate and %i unreferenced vertices from mesh %s\n",dup,unref,argv[1]);
-  int Step= atoi(argv[2]);
 
   tri::UpdateTopology<MyMesh>::VertexFace(m);