diff --git a/CurveAux.cpp b/CurveAux.cpp
index 56a9448..dc6fba1 100644
--- a/CurveAux.cpp
+++ b/CurveAux.cpp
@@ -136,5 +136,182 @@ ArcToBezierCurve( const ICurve* pCrv, ICurve*& pCrvNew)
       pCrvNew = Release( pCrvCompo) ;
    }
 
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+NurbsCurveCanonicalize( CNurbsData& cnData)
+{
+  // se periodica
+   if ( cnData.bPeriodic) {
+     // va trasformata in non-periodica (clamped)
+     // vedere The NurbsBook di Les Piegl e Tiller
+     // mancano esempi per testare
+      return false ;
+   }
+  // se con nodi extra
+   if ( cnData.bExtraKnotes) {
+      int nKnotesNbr = int( cnData.vU.size()) ;
+      if ( nKnotesNbr < 4)
+         return false ;
+      cnData.bExtraKnotes = false ;
+      for ( int i = 0 ; i < nKnotesNbr - 2 ; ++ i)
+         cnData.vU[i] = cnData.vU[i+1] ;
+      cnData.vU.resize( nKnotesNbr - 2) ;
+      return true ;
+   }
+
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+NurbsToBezierCurve( const CNurbsData& cnData, ICurve*& pCrvNew)
+{
+  // la curva Nurbs deve essere in forma canonica
+   if ( cnData.bPeriodic  ||  cnData.bExtraKnotes)
+      return false ;
+  // numero dei nodi
+   int nU = int( cnData.vCP.size()) + cnData.nDeg - 1 ;
+  // controllo relazione nodi - punti di controllo
+   if ( nU != int( cnData.vU.size()))
+      return false ;
+  // numero degli intervalli
+   int nInt = nU - 2 * cnData.nDeg + 1 ;
+
+  // se 1 solo intervallo, la Nurbs è già una curva di Bezier
+   if ( nInt == 1) {
+     // creo la curva di Bezier
+      PtrOwner<ICurveBezier> pCrvBez( CreateCurveBezier()) ;
+      if ( ! IsValid( pCrvBez))
+         return false ;
+     // la inizializzo
+      if ( ! pCrvBez->Init( cnData.nDeg, cnData.bRat))
+         return false ;
+      for ( int i = 0 ; i <= cnData.nDeg ; ++ i) {
+         if ( ! cnData.bRat) {
+            if ( ! pCrvBez->SetControlPoint( i, cnData.vCP[i]))
+               return false ;
+         }
+         else {
+            if ( ! pCrvBez->SetControlPoint( i, cnData.vCP[i], cnData.vW[i]))
+               return false ;
+         }
+      }
+     // restituisco la curva
+      pCrvNew = Release( pCrvBez) ;
+      return true ;
+   }
+
+  // altrimenti è equivalente ad una curva composita, la creo
+   PtrOwner<ICurveComposite> pCrvCompo( CreateCurveComposite()) ;
+   if ( ! IsValid( pCrvCompo))
+      return false ;
+
+  // vettore dei punti di controllo della curva di Bezier
+   PNTVECTOR vBC ;
+   vBC.resize( cnData.nDeg + 1) ;
+   DBLVECTOR vBW ;
+   vBW.resize( cnData.nDeg + 1) ;
+   if ( ! cnData.bRat) {
+      for ( int i = 0 ; i <= cnData.nDeg ; ++ i)
+         vBC[i] = cnData.vCP[i] ;
+   }
+   else {
+      for ( int i = 0 ; i <= cnData.nDeg ; ++ i) {
+         vBC[i] = cnData.vCP[i] * cnData.vW[i] ;
+         vBW[i] = cnData.vW[i] ;
+      }
+   }
+  // primi coefficienti della successiva
+   PNTVECTOR vNextBC ;
+   vNextBC.resize( cnData.nDeg - 1) ;
+   DBLVECTOR vNextBW ;
+   vNextBW.resize( cnData.nDeg - 1) ;
+  // ...
+   DBLVECTOR vAlfa ;
+   vAlfa.resize( cnData.nDeg - 1) ;
+   int a = cnData.nDeg - 1 ;
+   int b = cnData.nDeg ;
+  // ciclo
+   while ( b < nU - 1) {
+      int i = b ;
+      while ( b < nU - 1  &&  fabs( cnData.vU[b+1] - cnData.vU[b]) < EPS_ZERO)
+         ++ b ;
+      int mult = std::min( b - i + 1, cnData.nDeg) ;
+      if ( mult < cnData.nDeg) {
+        // numeratore di alfa
+         double numer = cnData.vU[b] - cnData.vU[a] ;
+        // calcola e salva gli alfa
+         for ( int j = cnData.nDeg ; j > mult ; -- j)
+            vAlfa[j-mult-1] = numer / ( cnData.vU[a+j] - cnData.vU[a]) ;
+        // inserisco il nodo r volte
+         int r = cnData.nDeg - mult ;
+         for ( int j = 1 ; j <= r ; ++ j) {
+            int save = r - j ;
+            int s = mult + j ;
+            for ( int k = cnData.nDeg ; k >= s ; -- k)
+               vBC[k] = vAlfa[k-s] * vBC[k] + ( 1 - vAlfa[k-s]) * vBC[k-1] ;
+            if ( cnData.bRat) {
+               for ( int k = cnData.nDeg ; k >= s ; -- k)
+                  vBW[k] = vAlfa[k-s] * vBW[k] + ( 1 - vAlfa[k-s]) * vBW[k-1] ;
+            }
+            if ( b < nU - 1) {
+               vNextBC[save] = vBC[cnData.nDeg] ;
+               if ( cnData.bRat)
+                  vNextBW[save] = vBW[cnData.nDeg] ;
+            }
+         }
+      }
+
+     // costruisco la curva di Bezier e la inserisco nella curva composita
+      PtrOwner<ICurveBezier> pCrvBez( CreateCurveBezier()) ;
+      if ( ! IsValid( pCrvBez))
+         return false ;
+     // la inizializzo
+      if ( ! pCrvBez->Init( cnData.nDeg, cnData.bRat))
+         return false ;
+      if ( ! cnData.bRat) {
+         for ( int i = 0 ; i <= cnData.nDeg ; ++ i) {
+            if ( ! pCrvBez->SetControlPoint( i, vBC[i]))
+               return false ;
+         }
+      }
+      else {
+         for ( int i = 0 ; i <= cnData.nDeg ; ++ i) {
+            if ( ! pCrvBez->SetControlPoint( i, vBC[i] / vBW[i], vBW[i]))
+               return false ;
+         }
+      }
+     // la aggiungo alla curva composita
+      if ( ! pCrvCompo->AddCurve( Release( pCrvBez)))
+         return false ;
+
+     // inizializzazioni per la prossima curva di Bezier
+      if ( b < nU - 1) {
+         if ( ! cnData.bRat) {
+            for ( int i = 0 ; i < cnData.nDeg - 1 ; ++ i)
+               vBC[i] = vNextBC[i] ;
+            for ( int i = cnData.nDeg - mult ; i <= cnData.nDeg ; ++ i)
+               vBC[i] = cnData.vCP[b-cnData.nDeg+i+1] ;
+         }
+         else {
+            for ( int i = 0 ; i < cnData.nDeg - 1 ; ++ i) {
+               vBC[i] = vNextBC[i] ;
+               vBW[i] = vNextBW[i] ;
+            }
+            for ( int i = cnData.nDeg - mult ; i <= cnData.nDeg ; ++ i) {
+               vBC[i] = cnData.vCP[b-cnData.nDeg+i+1] * cnData.vW[b-cnData.nDeg+i+1] ;
+               vBW[i] = cnData.vW[b-cnData.nDeg+i+1] ;
+            }
+         }
+         a = b ;
+         ++ b ;
+      }
+   }
+
+  // restituisco la curva composita
+   pCrvNew = Release( pCrvCompo) ;
    return true ;
 }
\ No newline at end of file
diff --git a/CurveAux.h b/CurveAux.h
index 0caf30e..5e6219a 100644
--- a/CurveAux.h
+++ b/CurveAux.h
@@ -13,14 +13,10 @@
 
 #pragma once
 
-#include "/EgtDev/Include/EGkCurve.h"
+#include "/EgtDev/Include/EgkCurveAux.h"
 
 //----------------------------------------------------------------------------
 bool IsClosed( const ICurve& crvC) ;
 bool GetTang( const ICurve& crvC, double dU, ICurve::Side nS, Vector3d& vtTang) ;
 bool GetPointTang( const ICurve& crvC, double dU, ICurve::Side nS, Point3d& ptPos, Vector3d& vtTang) ;
 bool GetPointDiffGeom( const ICurve& crvC, double dU, ICurve::Side nS, CrvPointDiffGeom& oDiffG) ;
-
-//----------------------------------------------------------------------------
-// trasforma un arco in una curva di Bezier semplice o composta
-bool ArcToBezierCurve( const ICurve* pArc, ICurve*& pCrvNew) ;
diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index 82ec3a5..abea144 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/EgtGeomKernel.vcxproj b/EgtGeomKernel.vcxproj
index e4059da..f4633cd 100644
--- a/EgtGeomKernel.vcxproj
+++ b/EgtGeomKernel.vcxproj
@@ -278,6 +278,7 @@ copy $(TargetPath) \EgtProg\Dll64</Command>
     <ClInclude Include="..\Include\EGkColor.h" />
     <ClInclude Include="..\Include\EgkCurve.h" />
     <ClInclude Include="..\Include\EgkCurveArc.h" />
+    <ClInclude Include="..\Include\EgkCurveAux.h" />
     <ClInclude Include="..\Include\EgkCurveBezier.h" />
     <ClInclude Include="..\Include\EgkCurveComposite.h" />
     <ClInclude Include="..\Include\EgkCurveLine.h" />
diff --git a/EgtGeomKernel.vcxproj.filters b/EgtGeomKernel.vcxproj.filters
index cef2e26..eeaf350 100644
--- a/EgtGeomKernel.vcxproj.filters
+++ b/EgtGeomKernel.vcxproj.filters
@@ -407,6 +407,9 @@
     <ClInclude Include="..\Include\EGkPointGrid3d.h">
       <Filter>File di intestazione</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\EgkCurveAux.h">
+      <Filter>File di intestazione</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="EgtGeomKernel.rc">