diff --git a/EGkDistPointCurve.h b/EGkDistPointCurve.h
index e0dca1c..b4b5b47 100644
--- a/EGkDistPointCurve.h
+++ b/EGkDistPointCurve.h
@@ -49,22 +49,23 @@ class DistPointCurve
       // Il flag bIsSegment vale solo per linee.
 
    public :
-      EGK_EXPORT bool GetSqDist( double& dSqDist) ;
-      EGK_EXPORT bool GetDist( double& dDist) ;
-      EGK_EXPORT bool IsEpsilon( double dTol)
-                        { double dSqDist ; return ( GetSqDist( dSqDist) && ( dSqDist < SQ_EPS_ZERO || dSqDist < dTol * dTol)) ; }
-      EGK_EXPORT bool IsSmall( void)
-                        { return IsEpsilon( EPS_SMALL) ; }
-      EGK_EXPORT bool IsZero( void)
-                        { return IsEpsilon( EPS_ZERO) ; }
-      EGK_EXPORT int  GetNbrMinDist( void) { return (int) m_Info.size() ; }
-      EGK_EXPORT bool GetMinDistPoint( int nInd, Point3d& ptMinDist, int& nFlag) ;
-      EGK_EXPORT bool GetMinDistPoint( double dNearParam, Point3d& ptMinDist, int& nFlag) ;
-      EGK_EXPORT bool GetParamAtMinDistPoint( int nInd, double& dParam, int& nFlag) ;
-      EGK_EXPORT bool GetParamAtMinDistPoint( double dNearParam, double& dParam, int& nFlag) ;
-      EGK_EXPORT bool GetSideAtMinDistPoint( int nInd, const Vector3d& vtN, int& nSide) ;
-      EGK_EXPORT bool GetSideAtMinDistPoint( double dNearParam, const Vector3d& vtN, int& nSide) ;
-      EGK_EXPORT bool GetMinDistInfo( int nInd, MinDistPCInfo& aInfo) ;
+      EGK_EXPORT bool GetSqDist( double& dSqDist) const ;
+      EGK_EXPORT bool GetDist( double& dDist) const ;
+      EGK_EXPORT bool IsEpsilon( double dTol) const
+                         { double dSqDist ; return ( GetSqDist( dSqDist) && ( dSqDist < SQ_EPS_ZERO || dSqDist < dTol * dTol)) ; }
+      EGK_EXPORT bool IsSmall( void) const
+                         { return IsEpsilon( EPS_SMALL) ; }
+      EGK_EXPORT bool IsZero( void) const
+                         { return IsEpsilon( EPS_ZERO) ; }
+      EGK_EXPORT int  GetNbrMinDist( void) const
+                         { return (int) m_Info.size() ; }
+      EGK_EXPORT bool GetMinDistPoint( int nInd, Point3d& ptMinDist, int& nFlag) const ;
+      EGK_EXPORT bool GetMinDistPoint( double dNearParam, Point3d& ptMinDist, int& nFlag) const ;
+      EGK_EXPORT bool GetParamAtMinDistPoint( int nInd, double& dParam, int& nFlag) const ;
+      EGK_EXPORT bool GetParamAtMinDistPoint( double dNearParam, double& dParam, int& nFlag) const ;
+      EGK_EXPORT bool GetSideAtMinDistPoint( int nInd, const Vector3d& vtN, int& nSide) const ;
+      EGK_EXPORT bool GetSideAtMinDistPoint( double dNearParam, const Vector3d& vtN, int& nSide) const ;
+      EGK_EXPORT bool GetMinDistInfo( int nInd, MinDistPCInfo& aInfo) const ;
 
    private :
       DistPointCurve( void) ;
diff --git a/EGkDistPointSurfTm.h b/EGkDistPointSurfTm.h
index c8ec942..43d7a1f 100644
--- a/EGkDistPointSurfTm.h
+++ b/EGkDistPointSurfTm.h
@@ -37,16 +37,16 @@ class DistPointSurfTm
       EGK_EXPORT DistPointSurfTm( const Point3d& ptP, const ISurfTriMesh& tmSurf) ;
 
    public :
-      EGK_EXPORT bool GetDist( double& dDist) ;
-      EGK_EXPORT bool IsEpsilon( double dTol)
+      EGK_EXPORT bool GetDist( double& dDist) const ;
+      EGK_EXPORT bool IsEpsilon( double dTol) const
                        { return ( m_dDist >= 0.  &&  ( m_dDist < EPS_ZERO || m_dDist < dTol)) ; }
-      EGK_EXPORT bool IsSmall( void)
+      EGK_EXPORT bool IsSmall( void) const
                        { return IsEpsilon( EPS_SMALL) ; }
-      EGK_EXPORT bool IsZero( void)
+      EGK_EXPORT bool IsZero( void) const
                        { return IsEpsilon( EPS_ZERO) ; }
-      EGK_EXPORT bool GetMinDistPoint( Point3d& ptMinDistPoint) ;
-      EGK_EXPORT bool GetMinDistTriaIndex( int& nMinDistTriaIndex) ;
-      EGK_EXPORT bool IsPointInside( void)
+      EGK_EXPORT bool GetMinDistPoint( Point3d& ptMinDistPoint) const ;
+      EGK_EXPORT bool GetMinDistTriaIndex( int& nMinDistTriaIndex) const ;
+      EGK_EXPORT bool IsPointInside( void) const
                         { return m_bIsInside ; }
 
    private :
diff --git a/EGkPolyLine.h b/EGkPolyLine.h
index a26e6dd..88de9de 100644
--- a/EGkPolyLine.h
+++ b/EGkPolyLine.h
@@ -136,8 +136,9 @@ class PolyLine
 
 //----------------------------------------------------------------------------
 // Raccolte di PolyLine
-typedef std::vector<PolyLine>  POLYLINEVECTOR ;   // vettore di PolyLine
-typedef std::list<PolyLine>    POLYLINELIST ;     // lista di PolyLine
+typedef std::vector<PolyLine>        POLYLINEVECTOR ;   // vettore di PolyLine
+typedef std::list<PolyLine>          POLYLINELIST ;     // lista di PolyLine
+typedef std::vector<POLYLINEVECTOR>  POLYLINEMATRIX ;   // matrice di PolyLine
 
 //----------------------------------------------------------------------------
 EGK_EXPORT bool DistPointPolyLine( const Point3d& ptP, const PolyLine& plPoly, double& dDist) ;
diff --git a/EGkStmFromTriangleSoup.h b/EGkStmFromTriangleSoup.h
index f417910..e444c0a 100644
--- a/EGkStmFromTriangleSoup.h
+++ b/EGkStmFromTriangleSoup.h
@@ -36,14 +36,13 @@ class StmFromTriangleSoup
       EGK_EXPORT bool Start( int nBuckets = GRID_STD_BUCKETS) ;
       EGK_EXPORT bool AddTriangle( const Triangle3d& Tria) ;
       EGK_EXPORT bool AddTriangle( const Point3d& ptP0, const Point3d& ptP1, const Point3d& ptP2,
-                 const double dU0 = -1, const double dV0 = -1, const double dU1 = -1, const double dV1 = -1,
-                 const double dU2 = -1, const double dV2 = -1) ;
+                                   double dU0 = -1, double dV0 = -1, double dU1 = -1, double dV1 = -1, double dU2 = -1, double dV2 = -1) ;
       EGK_EXPORT bool AddSurfTriMesh( const ISurfTriMesh& stmSource) ;
       EGK_EXPORT bool End( void) ;
       EGK_EXPORT ISurfTriMesh* GetSurf( void) ;
 
    private :
-      inline int AddVertex( const Point3d& ptP, const double dU = -1, const double dV = -1) ;
+      inline int AddVertex( const Point3d& ptP, double dU = -1, double dV = -1) ;
 
    private :
       ISurfTriMesh* m_pSTM ;
diff --git a/EGkSurfTriMesh.h b/EGkSurfTriMesh.h
index b9def3d..3510e12 100644
--- a/EGkSurfTriMesh.h
+++ b/EGkSurfTriMesh.h
@@ -43,7 +43,7 @@ class __declspec( novtable) ISurfTriMesh : public ISurf
       virtual void SetLinearTolerance( double dLinTol) = 0 ;
       virtual void SetBoundaryAngle( double dBoundaryAngDeg) = 0 ;
       virtual void SetSmoothAngle( double dSmoothAngDeg) = 0 ;
-      virtual int  AddVertex( const Point3d& ptVert, const double dU = -1, const double dV = -1) = 0 ;
+      virtual int  AddVertex( const Point3d& ptVert, double dU = -1, double dV = -1) = 0 ;
       virtual bool MoveVertex( int nInd, const Point3d& ptNewVert) = 0 ;
       virtual int  AddTriangle( const int nIdVert[3], int nTFlag = 0) = 0 ;
       virtual bool RemoveTriangle( int nId) = 0 ;
diff --git a/EgtExecMgr.h b/EgtExecMgr.h
index 92ad538..c54d5e9 100644
--- a/EgtExecMgr.h
+++ b/EgtExecMgr.h
@@ -37,7 +37,7 @@ class ExecManager
              { return m_pExecMap.insert( std::pair< std::string, Exec>( sName, eFunc)).second ; }
 
       int Execute( T& Executor, const std::string& sCmd1, const std::string& sCmd2, const STRVECTOR& vsParams)
-             { KeyExecMap::iterator Iter = m_pExecMap.find( sCmd1) ;
+             { const auto Iter = m_pExecMap.find( sCmd1) ;
                if ( Iter != m_pExecMap.end()  &&  (Iter->second) != nullptr) {
                   if ( ( Executor.*(Iter->second))( sCmd2, vsParams))
                      return ER_OK ;
diff --git a/EgtLogger.h b/EgtLogger.h
index 3d44e0a..66a6051 100644
--- a/EgtLogger.h
+++ b/EgtLogger.h
@@ -109,8 +109,7 @@ namespace egtlogger
          
          void ClearOutputStreams( void)
          {
-            std::vector<StreamInfo>::iterator iter ;
-            for ( iter = m_outputStreams.begin(); iter < m_outputStreams.end() ; ++iter) {
+            for ( auto iter = m_outputStreams.cbegin() ; iter < m_outputStreams.cend() ; ++iter) {
                if ( iter->bOwned)
                   delete iter->pStream ;
             }
@@ -127,8 +126,7 @@ namespace egtlogger
          {
             m_threadProtect.Lock() ;
 
-            std::vector<StreamInfo>::iterator iter ;
-            for ( iter = m_outputStreams.begin() ; iter < m_outputStreams.end() ; ++iter) {
+            for ( auto iter = m_outputStreams.cbegin() ; iter < m_outputStreams.cend() ; ++iter) {
                if ( nLevel < iter->nLevel)
                   continue ;