diff --git a/EgtMachKernel.rc b/EgtMachKernel.rc
index 0a9e3ae..ec1857e 100644
Binary files a/EgtMachKernel.rc and b/EgtMachKernel.rc differ
diff --git a/OperationCL.cpp b/OperationCL.cpp
index 97635c5..08e8bc0 100644
--- a/OperationCL.cpp
+++ b/OperationCL.cpp
@@ -256,14 +256,21 @@ Operation::AddArcMove( const Point3d& ptP, const Point3d& ptCen, double dAngCen,
    PtrOwner<ICurveArc> pArc( CreateCurveArc()) ;
    if ( IsNull( pArc))
       return GDB_ID_NULL ;
+  // verifico normale arco rispetto a versore utensile, ed eventualmente modifico opportunamente
+   Vector3d vtMyN = vtN ;
+   double dMyAngCen = dAngCen ;
+   if ( vtMyN * m_vtTool < - EPS_ZERO) {
+      vtMyN = - vtMyN ;
+      dMyAngCen = - dMyAngCen ;
+   }
   // assegno i dati dell'arco
-   double dDeltaZ = ( ptP - m_ptCurr) * vtN ;
-   if ( ! pArc->SetCPAN( ptCen, m_ptCurr, dAngCen, dDeltaZ, vtN))
+   double dDeltaZ = ( ptP - m_ptCurr) * vtMyN ;
+   if ( ! pArc->SetCPAN( ptCen, m_ptCurr, dMyAngCen, dDeltaZ, vtMyN))
       return GDB_ID_NULL ;
    Point3d ptFin ;
    if ( ! pArc->GetEndPoint( ptFin)  ||  ! AreSamePointApprox( ptFin, ptP))
       return GDB_ID_NULL ;
-   int nMove = ( dAngCen > 0 ? 3 : 2) ;
+   int nMove = ( dMyAngCen > 0 ? 3 : 2) ;
   // inserisco l'oggetto nel DB geometrico
    int nId = m_pGeomDB->AddGeoObj( GDB_ID_NULL, m_nPathId, Release( pArc)) ;
    if ( nId == GDB_ID_NULL)
@@ -279,9 +286,9 @@ Operation::AddArcMove( const Point3d& ptP, const Point3d& ptCen, double dAngCen,
    pCam->SetAuxDir( m_vtAux) ;
    pCam->SetEndPoint( ptP) ;
    pCam->SetCenter( ptCen) ;
-   pCam->SetAngCen( dAngCen) ;
+   pCam->SetAngCen( dMyAngCen) ;
    pCam->SetDeltaN( dDeltaZ) ;
-   pCam->SetNormDir( vtN) ;
+   pCam->SetNormDir( vtMyN) ;
    pCam->SetFeed( m_dFeed) ;
    pCam->SetFlag( m_nFlag) ;
   // associo questo oggetto a quello geometrico