diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index f84e231..4fd7082 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/PolyLine.cpp b/PolyLine.cpp
index 9357389..466f77f 100644
--- a/PolyLine.cpp
+++ b/PolyLine.cpp
@@ -1513,3 +1513,82 @@ SplitPolyLineAtPoint( const PolyLine& plPoly, const Point3d& ptP, double dToler,
    plPoly2.AddUPoint( 0, ptP, false) ;
    return true ;
 }
+
+//----------------------------------------------------------------------------
+bool 
+AssociatePolyLinesMinDistPoints( const PolyLine& PL1, const PolyLine& PL2, PNTIVECTOR& vPnt1, PNTIVECTOR& vPnt2, bool& bCommonInternalPoints)
+{
+  // controllo che le polyline abbiano almeno un punto 
+   int nPnt1 = PL1.GetPointNbr() ;
+   int nPnt2 = PL2.GetPointNbr() ;
+   if ( nPnt1 == 0 || nPnt2 == 0)
+      return false ;
+        
+   bCommonInternalPoints = false ;   // indica la presenza di punti interni in comune tra le due polylines
+
+   vPnt1.reserve( PL1.GetPointNbr()) ;
+   Point3d ptP1 ;
+   bool bF1 = PL1.GetFirstPoint( ptP1) ;
+   while ( bF1) {
+      vPnt1.emplace_back( ptP1, -1) ;
+      bF1 = PL1.GetNextPoint( ptP1) ;
+   }
+   int nTotP1 = int( vPnt1.size()) ;
+
+   vPnt2.reserve( PL2.GetPointNbr()) ;
+   Point3d ptP2 ;
+   bool bF2 = PL2.GetFirstPoint( ptP2) ;
+   while ( bF2) {
+      vPnt2.emplace_back( ptP2, -1) ;
+      bF2 = PL2.GetNextPoint( ptP2) ;
+   }
+   int nTotP2 = int( vPnt2.size()) ;
+
+  // calcoli per prima curva
+   int LastJ = 0 ;
+   vPnt1[0].second = 0 ;
+   for ( int i = 1 ; i < nTotP1 ; ++ i) {
+      double dSqDistMin = SqDist( vPnt1[i].first, vPnt2[LastJ].first) ;
+      double dApprDistMin = ApproxDist( vPnt1[i].first, vPnt2[LastJ].first) ;
+      int MinJ = LastJ ;
+      for ( int j = LastJ + 1 ; j < nTotP2 ; ++ j) {
+         double dSqDist = SqDist( vPnt1[i].first, vPnt2[j].first) ;
+         if ( dSqDist < dSqDistMin - 2 * dApprDistMin * EPS_SMALL) {
+            dSqDistMin = dSqDist ;
+            dApprDistMin = ApproxDist( vPnt1[i].first, vPnt2[j].first) ;
+            MinJ = j ;
+         }
+         else if ( dSqDist > 16 * dSqDistMin)
+            break ;
+      }
+      if ( i < nTotP1 - 1  &&  dSqDistMin < EPS_SMALL)
+         bCommonInternalPoints = true ;
+      vPnt1[i].second = MinJ ;
+      LastJ = MinJ ;
+   }
+   
+  // calcoli per seconda curva
+   int LastI = 0 ;
+   vPnt2[0].second = 0 ;
+   for ( int j = 1 ; j < nTotP2 ; ++ j) {
+      double dSqDistMin = SqDist( vPnt2[j].first, vPnt1[LastI].first) ;
+      double dApprDistMin = ApproxDist( vPnt2[j].first, vPnt1[LastI].first) ;
+      int MinI = LastI ;
+      for ( int i = LastI + 1 ; i < nTotP1 ; ++ i) {
+         double dSqDist = SqDist( vPnt2[j].first, vPnt1[i].first) ;
+         if ( dSqDist < dSqDistMin - 2 * dApprDistMin * EPS_SMALL) {
+            dSqDistMin = dSqDist ;
+            dApprDistMin = ApproxDist( vPnt2[j].first, vPnt1[i].first) ;
+            MinI = i ;
+         }
+         else if ( dSqDist > 16 * dSqDistMin)
+            break ;
+      }
+      if ( j < nTotP2 - 1  &&  dSqDistMin < EPS_SMALL)
+         bCommonInternalPoints = true ;
+      vPnt2[j].second = MinI ;
+      LastI = MinI ;
+   }
+
+   return true ;
+}
\ No newline at end of file
diff --git a/SurfTriMesh.cpp b/SurfTriMesh.cpp
index aa72184..2acf8db 100644
--- a/SurfTriMesh.cpp
+++ b/SurfTriMesh.cpp
@@ -2141,79 +2141,26 @@ SurfTriMesh::CreateByTwoCurves( const PolyLine& PL1, const PolyLine& PL2, int nR
    ResetHashGrids3d() ;
 
   // se rigata a minima distanza tra le due curve
-   if ( nRuledType == RLT_MINDIST) {
+   if ( nRuledType == RLT_MINDIST) {      
      // verifico ci siano almeno due punti diversi per curva
       if ( ( PL1.IsClosed()  &&  PL1.GetPointNbr() < 3)  ||  PL1.GetPointNbr() < 2)
          return false ;
       if ( ( PL2.IsClosed()  &&  PL2.GetPointNbr() < 3)  ||  PL2.GetPointNbr() < 2)
-         return false ;
-
+         return false ;    
+      
      // flag di curve entrambe chiuse e correzione conseguente a numero totale punti differenti
       bool bClosed = PL1.IsClosed() && PL2.IsClosed() ;
 
-     // vettori punti con primo punto dell'altra curva a distanza minima
-      PNTUVECTOR vPnt1 ;
-      vPnt1.reserve( PL1.GetPointNbr()) ;
-      Point3d ptP1 ;
-      bool bF1 = PL1.GetFirstPoint( ptP1) ;
-      while ( bF1) {
-         vPnt1.emplace_back( ptP1, -1) ;
-         bF1 = PL1.GetNextPoint( ptP1) ;
-      }
-      int nTotP1 = int( vPnt1.size()) ;
-      PNTUVECTOR vPnt2 ;
-      vPnt2.reserve( PL2.GetPointNbr()) ;
-      Point3d ptP2 ;
-      bool bF2 = PL2.GetFirstPoint( ptP2) ;
-      while ( bF2) {
-         vPnt2.emplace_back( ptP2, -1) ;
-         bF2 = PL2.GetNextPoint( ptP2) ;
-      }
+     // vettori punti con indice del primo punto dell'altra curva a distanza minima
+      PNTIVECTOR vPnt1, vPnt2 ;
+      bool bCommonInternalPoints ; 
+      if ( ! AssociatePolyLinesMinDistPoints( PL1, PL2, vPnt1, vPnt2, bCommonInternalPoints))
+         return false ;
+     // verifico che non ci siano punti interni in comune
+      if ( bCommonInternalPoints)
+         return false ;
+      int nTotP1 = int( vPnt1.size()) ; 
       int nTotP2 = int( vPnt2.size()) ;
-     // calcoli per prima curva
-      int LastJ = 0 ;
-      vPnt1[0].second = 0 ;
-      for ( int i = 1 ; i < nTotP1 ; ++ i) {
-         double dSqDistMin = SqDist( vPnt1[i].first, vPnt2[LastJ].first) ;
-         double dApprDistMin = ApproxDist( vPnt1[i].first, vPnt2[LastJ].first) ;
-         int MinJ = LastJ ;
-         for ( int j = LastJ + 1 ; j < nTotP2 ; ++ j) {
-            double dSqDist = SqDist( vPnt1[i].first, vPnt2[j].first) ;
-            if ( dSqDist < dSqDistMin - 2 * dApprDistMin * EPS_SMALL) {
-               dSqDistMin = dSqDist ;
-               dApprDistMin = ApproxDist( vPnt1[i].first, vPnt2[j].first) ;
-               MinJ = j ;
-            }
-            else if ( dSqDist > 16 * dSqDistMin)
-               break ;
-         }
-         if ( i < nTotP1 - 1  &&  dSqDistMin < EPS_SMALL)
-            return false ;
-         vPnt1[i].second = MinJ ;
-         LastJ = MinJ ;
-      }
-     // calcoli per seconda curva
-      int LastI = 0 ;
-      vPnt2[0].second = 0 ;
-      for ( int j = 1 ; j < nTotP2 ; ++ j) {
-         double dSqDistMin = SqDist( vPnt2[j].first, vPnt1[LastI].first) ;
-         double dApprDistMin = ApproxDist( vPnt2[j].first, vPnt1[LastI].first) ;
-         int MinI = LastI ;
-         for ( int i = LastI + 1 ; i < nTotP1 ; ++ i) {
-            double dSqDist = SqDist( vPnt2[j].first, vPnt1[i].first) ;
-            if ( dSqDist < dSqDistMin - 2 * dApprDistMin * EPS_SMALL) {
-               dSqDistMin = dSqDist ;
-               dApprDistMin = ApproxDist( vPnt2[j].first, vPnt1[i].first) ;
-               MinI = i ;
-            }
-            else if ( dSqDist > 16 * dSqDistMin)
-               break ;
-         }
-         if ( j < nTotP2 - 1  &&  dSqDistMin < EPS_SMALL)
-            return false ;
-         vPnt2[j].second = MinI ;
-         LastI = MinI ;
-      }
  
      // Costruisco la mesh
       int nVertNbr =  nTotP1 + nTotP2 ;
@@ -2317,7 +2264,7 @@ SurfTriMesh::CreateByTwoCurves( const PolyLine& PL1, const PolyLine& PL2, int nR
       if ( ! VerifyPolylinesForTwoCurves( PL1, PL2))
          return false ;
 
-     // flag di curve chiuse
+     // flag di curve chiuse 
       bool bClosed = PL1.IsClosed() && PL2.IsClosed() ;
      // recupero i parametri delle due polilinee
       double dU1F ; PL1.GetFirstU( dU1F) ;