diff --git a/SurfTriMesh.cpp b/SurfTriMesh.cpp
index 16f22f2..4402b1e 100644
--- a/SurfTriMesh.cpp
+++ b/SurfTriMesh.cpp
@@ -852,6 +852,9 @@ SurfTriMesh::GetTempInt( int nTriaId, int& nTempInt) const
 bool
 SurfTriMesh::GetTriangleSmoothNormal( int nT, int nV, Vector3d& vtN) const 
 {
+  // flag di pesatura con angolo al vertice
+   bool bAngWeighted = true ;
+   
   // recupero tutti i triangoli attorno al vertice
    bool bCirc ;
    INTVECTOR vT ;
@@ -871,14 +874,21 @@ SurfTriMesh::GetTriangleSmoothNormal( int nT, int nV, Vector3d& vtN) const
       return false ;
 
   // medio le normali, finchè non incontro degli spigoli
-   vtN = m_vTria[nT].vtN ;
+   double dAngW = 1 ;
+   if ( bAngWeighted)
+      GetTriangleVertexAngle( nT, nV, dAngW) ;
+   vtN = dAngW * m_vTria[nT].vtN ;
    // parto dal triangolo e vado in direzione positiva
    int nLim = nPos ;
    for ( int i = NextIndAroundVertex( nPos, nTria, bCirc) ;
          i != nPos && i < int( vT.size()) ;
          i = NextIndAroundVertex( i, nTria, bCirc)) {
-      if ( m_vTria[vT[nPos]].vtN * m_vTria[vT[i]].vtN >= m_dCosSmAng)
-         vtN += m_vTria[vT[i]].vtN ;
+      if ( m_vTria[nT].vtN * m_vTria[vT[i]].vtN >= m_dCosSmAng) {
+         int nK ; double dAngW = 1 ;
+         if ( bAngWeighted  &&  FindVertexInTria( m_vTria[nT].nIdVert[nV], vT[i], nK))
+            GetTriangleVertexAngle( vT[i], nK, dAngW) ;
+         vtN += dAngW * m_vTria[vT[i]].vtN ;
+      }
       else
          break ;
       nLim = i ;
@@ -887,8 +897,12 @@ SurfTriMesh::GetTriangleSmoothNormal( int nT, int nV, Vector3d& vtN) const
    for ( int i = PrevIndAroundVertex( nPos, nTria, bCirc) ;
          i != nLim && i >= 0 ;
          i = PrevIndAroundVertex( i, nTria, bCirc)) {
-      if ( m_vTria[vT[nPos]].vtN * m_vTria[vT[i]].vtN >= m_dCosSmAng)
-         vtN += m_vTria[vT[i]].vtN ;
+      if ( m_vTria[nT].vtN * m_vTria[vT[i]].vtN >= m_dCosSmAng) {
+         int nK ; double dAngW = 1 ;
+         if ( bAngWeighted  &&  FindVertexInTria( m_vTria[nT].nIdVert[nV], vT[i], nK))
+            GetTriangleVertexAngle( vT[i], nK, dAngW) ;
+         vtN += dAngW * m_vTria[vT[i]].vtN ;
+      }
       else
          break ;
    }
@@ -897,6 +911,23 @@ SurfTriMesh::GetTriangleSmoothNormal( int nT, int nV, Vector3d& vtN) const
    return true ;
 }
 
+//----------------------------------------------------------------------------
+bool
+SurfTriMesh::GetTriangleVertexAngle( int nT, int nV, double& dAng) const 
+{
+  // verifico esistenza del triangolo e validità vertice
+   if ( nT < 0  ||  nT >= GetTriangleSize()  ||  m_vTria[nT].nIdVert[0] == SVT_DEL  ||  nV < 0  ||  nV > 2)
+      return false ;
+  // determino i vettori dei due lati che partono dal vertice
+   Point3d ptVert = m_vVert[ m_vTria[nT].nIdVert[nV]].ptP ;
+   Point3d ptPrev = m_vVert[ m_vTria[nT].nIdVert[Prev( nV)]].ptP ;
+   Point3d ptNext = m_vVert[ m_vTria[nT].nIdVert[Next( nV)]].ptP ;
+   Vector3d vtPrev = ptPrev - ptVert ;
+   Vector3d vtNext = ptNext - ptVert ;
+  // determino l'angolo tra i due lati
+   return vtPrev.GetAngle( vtNext, dAng) ;
+}
+
 //----------------------------------------------------------------------------
 SurfTriMesh*
 SurfTriMesh::CloneTriangle( int nT) const
diff --git a/SurfTriMesh.h b/SurfTriMesh.h
index 49b92a7..3ab9637 100644
--- a/SurfTriMesh.h
+++ b/SurfTriMesh.h
@@ -414,6 +414,7 @@ class SurfTriMesh : public ISurfTriMesh, public IGeoObjRW
       int  NextIndAroundVertex( int nInd, int nSize, bool bCirc) const ;
       int  PrevIndAroundVertex( int nInd, int nSize, bool bCirc) const ;
       bool GetTriangleSmoothNormal( int nT, int nV, Vector3d& vtN) const ;
+      bool GetTriangleVertexAngle( int nT, int nV, double& dAng) const ;
       bool MarchAlongLoop( int nT, int nV, int nTimeStamp, PolyLine& PL) const ;
       bool MarchOneTria( int& nT, int& nV, int nTimeStamp, PolyLine& PL, bool& bEnd) const ;
       bool VerifyPolylinesForTwoCurves( const PolyLine&  PL1, const PolyLine&  PL2) const ;
diff --git a/VolZmapVolume.cpp b/VolZmapVolume.cpp
index bd28b54..2fa726a 100644
--- a/VolZmapVolume.cpp
+++ b/VolZmapVolume.cpp
@@ -1697,6 +1697,9 @@ VolZmap::Comp_5AxisMilling( int nGrid, const Point3d& ptS, const Point3d& ptE, c
         PtrOwner<CurveBezier> cBezTipEndF1(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipEndF1, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTipStartF2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipStartF2, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTipEndF2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipEndF2, nDegU, bRat)));
+       // !!!! DA SISTEMARE !!!!  
+        if ( IsNull( cBezTipStartF1)  ||  IsNull( cBezTipEndF1)  ||  IsNull( cBezTipStartF2)  ||  IsNull( cBezTipEndF2))
+           return true ;
         // archi inferiori back
         CurveArc cArcTipStartB1, cArcTipEndB1, cArcTipStartB2, cArcTipEndB2;
         cArcTipStartB1.SetC2PN(ptP1T, vPntTipStartBack[0], vPntTipStartBack[1], vtLs);
@@ -1707,6 +1710,9 @@ VolZmap::Comp_5AxisMilling( int nGrid, const Point3d& ptS, const Point3d& ptE, c
         PtrOwner<CurveBezier> cBezTipEndB1(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipEndB1, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTipStartB2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipStartB2, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTipEndB2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTipEndB2, nDegU, bRat)));
+       // !!!! DA SISTEMARE !!!!  
+        if ( IsNull( cBezTipStartB1)  ||  IsNull( cBezTipEndB1)  ||  IsNull( cBezTipStartB2)  ||  IsNull( cBezTipEndB2))
+           return true ;
         // archi superiori front
         CurveArc cArcTopStartF1, cArcTopEndF1, cArcTopStartF2, cArcTopEndF2;
         cArcTopStartF1.SetC2PN(ptS, vPntTopStartFront[0], vPntTopStartFront[1], vtLs);
@@ -1717,6 +1723,9 @@ VolZmap::Comp_5AxisMilling( int nGrid, const Point3d& ptS, const Point3d& ptE, c
         PtrOwner<CurveBezier> cBezTopEndF1(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopEndF1, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTopStartF2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopStartF2, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTopEndF2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopEndF2, nDegU, bRat)));
+       // !!!! DA SISTEMARE !!!!  
+        if ( IsNull( cBezTopStartF1)  ||  IsNull( cBezTopEndF1)  ||  IsNull( cBezTopStartF2)  ||  IsNull( cBezTopEndF2))
+           return true ;
         // archi superiori back
         CurveArc cArcTopStartB1, cArcTopEndB1, cArcTopStartB2, cArcTopEndB2;
         cArcTopStartB1.SetC2PN(ptS, vPntTopStartBack[0], vPntTopStartBack[1], vtLs);
@@ -1727,6 +1736,9 @@ VolZmap::Comp_5AxisMilling( int nGrid, const Point3d& ptS, const Point3d& ptE, c
         PtrOwner<CurveBezier> cBezTopEndB1(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopEndB1, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTopStartB2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopStartB2, nDegU, bRat)));
         PtrOwner<CurveBezier> cBezTopEndB2(GetBasicCurveBezier(ArcToBezierCurve(&cArcTopEndB2, nDegU, bRat)));
+       // !!!! DA SISTEMARE !!!!  
+        if ( IsNull( cBezTopStartB1)  ||  IsNull( cBezTopEndB1)  ||  IsNull( cBezTopStartB2)  ||  IsNull( cBezTopEndB2))
+           return true ;
 
         if ( n5AxisType == Move5Axis::NO_BASE_INTERS || n5AxisType == Move5Axis::ACROSS) {
             // inferiori