diff --git a/apps/sample/trimesh_curvature/trimesh_curvature.cpp b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
index 8569c6e5..47104819 100644
--- a/apps/sample/trimesh_curvature/trimesh_curvature.cpp
+++ b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
@@ -23,46 +23,86 @@
 /*! \file trimesh_curvature.cpp
 \ingroup code_sample
 
-\brief an example showing the various techniques for computing curvatures
+\brief an example showing various techniques for computing curvatures
 
 */
 #include <vcg/complex/complex.h>
 
 #include <vcg/complex/algorithms/create/platonic.h>
 #include <vcg/complex/algorithms/update/curvature.h>
+#include <vcg/complex/algorithms/update/curvature_fitting.h>
 
-#include<wrap/io_trimesh/export_off.h>
+#include<wrap/io_trimesh/export_ply.h>
 
-class MyEdge;
 class MyFace;
 class MyVertex;
 struct MyUsedTypes : public vcg::UsedTypes<	vcg::Use<MyVertex>   ::AsVertexType,
-                                            vcg::Use<MyEdge>     ::AsEdgeType,
                                             vcg::Use<MyFace>     ::AsFaceType>{};
 
-class MyVertex  : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::VFAdj, vcg::vertex::CurvatureDirf, vcg::vertex::Curvaturef, vcg::vertex::BitFlags  >{};
-class MyFace    : public vcg::Face< MyUsedTypes, vcg::face::FFAdj, vcg::face::VFAdj, vcg::face::VertexRef, vcg::face::BitFlags > {};
-class MyEdge    : public vcg::Edge<MyUsedTypes>{};
-class MyMesh    : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> , std::vector<MyEdge>  > {};
+class MyVertex  : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::VFAdj, vcg::vertex::Qualityf, vcg::vertex::CurvatureDirf, vcg::vertex::BitFlags  >{};
+class MyFace    : public vcg::Face< MyUsedTypes, vcg::face::FFAdj, vcg::face::VFAdj, vcg::face::Normal3f, vcg::face::VertexRef, vcg::face::BitFlags > {};
+class MyMesh    : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> > {};
 
 int main( int /*argc*/, char **/*argv*/ )
 {
   MyMesh m;
-  vcg::tri::Torus(m,30,10);
+  // in a torus with radii 1 and 4
+  // on the outside the principal curvature should be 1 and  1/5 
+  // and internally the principal curvature  should be 1 and -1/3
+  // Gaussian range -0.333 ..  0.200
+  // mean     range  0.333 ..  0.600
+  //vcg::tri::Torus(m,4,1,32,16);
+  
+  
+  // in a sphere of radius 2 the curvature is everywhere 0.5
+  // Gaussian 0.25
+  // Mean     0.5
+  vcg::tri::Sphere(m,5);
+  vcg::tri::UpdatePosition<MyMesh>::Scale(m, 2.0);
   
   vcg::tri::UpdateTopology<MyMesh>::FaceFace(m);
   vcg::tri::UpdateTopology<MyMesh>::VertexFace(m);
+  vcg::tri::UpdateNormal<MyMesh>::PerVertexNormalizedPerFaceNormalized(m); 
+  vcg::Distribution<float> distr;
+  printf("Starting mesh  vn:%i fn:%i\n",m.VN(),m.FN());
   
-  // Two different techniques for computing Discrete Gaussian and Mean Curvature
-  // they require the presence of the vertex::Curvature component
-  vcg::tri::UpdateCurvature<MyMesh>::PerVertex(m);
+  // Method 1 (discrete - Optimizing 3d triangulations using discrete curvature analysis 2003) 
+  vcg::tri::UpdateCurvature<MyMesh>::PerVertexAbsoluteMeanAndGaussian(m);
+  vcg::tri::UpdateQuality<MyMesh>::VertexFromAttributeName(m,"KG");
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Gaussian Curvature method 1 Min %f Max %f\n",distr.Min(),distr.Max());
+  vcg::tri::UpdateQuality<MyMesh>::VertexFromAttributeName(m,"KH");
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Mean     Curvature method 1 Min %f Max %f\n",distr.Min(),distr.Max());
+  
+  // Method 2 (discrete - Discrete Differential-Geometry Operators for Triangulated 2-Manifolds 2002)
   vcg::tri::UpdateCurvature<MyMesh>::MeanAndGaussian(m);
+  vcg::tri::UpdateQuality<MyMesh>::VertexFromAttributeName(m,"KG");
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Gaussian Curvature method 2 Min %f Max %f\n",distr.Min(),distr.Max());
+  vcg::tri::UpdateQuality<MyMesh>::VertexFromAttributeName(m,"KH");
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Mean     Curvature method 2 Min %f Max %f\n",distr.Min(),distr.Max());
+  vcg::tri::io::ExporterPLY<MyMesh>::Save(m,"Torus_Discrete_Mean2.ply",vcg::tri::io::Mask::IOM_VERTQUALITY);
   
-  // Two different techniques for computing Principal Curvature Directions 
-  // they require the presence of the vertex::CurvatureDir component
+  // Method 3 (directions - Estimating the Tensor of Curvature of a Surface from a Polyhedral Approximation - 1995)
   vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirections(m);
+  vcg::tri::UpdateQuality<MyMesh>::VertexGaussianFromCurvatureDir(m);
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Gaussian Curvature method 3 Min %f Max %f\n",distr.Min(),distr.Max());
+  vcg::tri::UpdateQuality<MyMesh>::VertexMeanFromCurvatureDir(m);
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Mean     Curvature method 3 Min %f Max %f\n",distr.Min(),distr.Max());
+  
+  // Method 4 (directions - Restricted delaunay triangulations and normal cycle )
   vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirectionsNormalCycle(m);
-  printf("Input mesh  vn:%i fn:%i\n",m.VN(),m.FN());
-
+  vcg::tri::UpdateQuality<MyMesh>::VertexGaussianFromCurvatureDir(m);
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Gaussian Curvature method 4 Min %f Max %f\n",distr.Min(),distr.Max());
+  vcg::tri::UpdateQuality<MyMesh>::VertexMeanFromCurvatureDir(m);
+  vcg::tri::Stat<MyMesh>::ComputePerVertexQualityDistribution(m,distr);
+  printf("Mean     Curvature method 4 Min %f Max %f\n",distr.Min(),distr.Max());
+  
+  
   return 0;
 }
diff --git a/apps/sample/trimesh_curvature/trimesh_curvature.pro b/apps/sample/trimesh_curvature/trimesh_curvature.pro
index 8342dfa4..343a355e 100644
--- a/apps/sample/trimesh_curvature/trimesh_curvature.pro
+++ b/apps/sample/trimesh_curvature/trimesh_curvature.pro
@@ -1,3 +1,3 @@
 include(../common.pri)
 TARGET = trimesh_curvature
-SOURCES += trimesh_curvature.cpp
+SOURCES += trimesh_curvature.cpp ../../../wrap/ply/plylib.cpp