diff --git a/Trimming.cpp b/Trimming.cpp
index 0d9df4c..48d7b46 100644
--- a/Trimming.cpp
+++ b/Trimming.cpp
@@ -3920,8 +3920,50 @@ GetTrimmingSyncInterpolation( const ICurve* pCrvEdge1, const ICurve* pCrvEdge2,
       return false ;
 
   // Recupero i due tratti di curva
-   PtrOwner<CurveComposite> pCompoGuide1( ConvertCurveToBasicComposite( pCrvEdge1->CopyParamRange( dUA, dUC))) ;
-   PtrOwner<CurveComposite> pCompoGuide2( ConvertCurveToBasicComposite( pCrvEdge2->CopyParamRange( dUB, dUD))) ;
+   PtrOwner<CurveComposite> pCompoGuide1( nullptr) ;
+   PtrOwner<CurveComposite> pCompoGuide2( nullptr) ;
+  // se entrambe chiuse
+   if ( pCrvEdge1->IsClosed()  &&  pCrvEdge2->IsClosed()) {
+     // Recupero la porzione di curva di Edge1 di lunghezza minima tra il parametro A e C
+      PtrOwner<CurveComposite> pCompoAC( ConvertCurveToBasicComposite( pCrvEdge1->CopyParamRange( dUA, dUC))) ;
+      PtrOwner<CurveComposite> pCompoCA( ConvertCurveToBasicComposite( pCrvEdge1->CopyParamRange( dUC, dUA))) ;
+      if ( IsNull( pCompoAC)  ||  IsNull( pCompoCA)  ||  ! pCompoAC->IsValid()  ||  ! pCompoCA->IsValid())
+         return false ;
+      double dLenAC ; pCompoAC->GetLength( dLenAC) ;
+      double dLenCA ; pCompoCA->GetLength( dLenCA) ;
+      if ( dLenAC < dLenCA)
+         pCompoGuide1.Set( Release( pCompoAC)) ;
+      else
+         pCompoGuide1.Set( Release( pCompoCA)) ;
+     // Recupero la porzione di curva di Edge2 di lunghezza minima tra il parametro B e D
+      PtrOwner<CurveComposite> pCompoBD( ConvertCurveToBasicComposite( pCrvEdge2->CopyParamRange( dUB, dUD))) ;
+      PtrOwner<CurveComposite> pCompoDB( ConvertCurveToBasicComposite( pCrvEdge2->CopyParamRange( dUD, dUB))) ;
+      if ( IsNull( pCompoBD)  ||  IsNull( pCompoBD)  ||  ! pCompoBD->IsValid()  ||  ! pCompoDB->IsValid())
+         return false ;
+      double dLenBD ; pCompoBD->GetLength( dLenBD) ;
+      double dLenDB ; pCompoDB->GetLength( dLenDB) ;
+      if ( dLenBD < dLenDB)
+         pCompoGuide2.Set( Release( pCompoBD)) ;
+      else
+         pCompoGuide2.Set( Release( pCompoDB)) ;
+   }
+  // se entrambe aperte
+   else if ( ! pCrvEdge1->IsClosed()  &&  ! pCrvEdge2->IsClosed()) {
+      pCompoGuide1.Set( ConvertCurveToBasicComposite( pCrvEdge1->Clone())) ;
+      if ( IsNull( pCompoGuide1)  ||  ! pCompoGuide1->IsValid())
+         return false ;
+      if ( dUA < dUC)
+         pCompoGuide1->TrimStartEndAtParam( dUA, dUC) ;
+      else
+         pCompoGuide1->TrimStartEndAtParam( dUC, dUA) ;
+      pCompoGuide2.Set( ConvertCurveToBasicComposite( pCrvEdge2->Clone())) ;
+      if ( IsNull( pCompoGuide2)  ||  ! pCompoGuide2->IsValid())
+         return false ;
+      if ( dUB < dUD)
+         pCompoGuide2->TrimStartEndAtParam( dUB, dUD) ;
+      else
+         pCompoGuide2->TrimStartEndAtParam( dUD, dUB) ;
+   }
    if ( IsNull( pCompoGuide1)  ||  IsNull( pCompoGuide2)  ||
         ! pCompoGuide1->IsValid()  ||  ! pCompoGuide2->IsValid())
       return false ;
@@ -3935,10 +3977,11 @@ GetTrimmingSyncInterpolation( const ICurve* pCrvEdge1, const ICurve* pCrvEdge2,
       swap( pCompoGuide1, pCompoGuide2) ;
       swap( dLen1, dLen2) ;
    }
-   if ( pCompoGuide2->IsPointOn( ptS1))
-      swap( ptS1, ptE1) ;
-   if ( pCompoGuide2->IsPointOn( ptS2))
-      swap( ptS2, ptE2) ;
+  // Aggiorno gli estremi delle curve
+   pCompoGuide1->GetStartPoint( ptS1) ;
+   pCompoGuide2->GetStartPoint( ptE1) ;
+   pCompoGuide1->GetEndPoint( ptS2) ;
+   pCompoGuide2->GetEndPoint( ptE2) ;
 
    #if DEBUG_SYNC_INTERPOLATION
       VT.clear() ; VC.clear() ;