diff --git a/Pocketing.cpp b/Pocketing.cpp
index 061da4a..eac4738 100644
--- a/Pocketing.cpp
+++ b/Pocketing.cpp
@@ -3690,6 +3690,9 @@ Pocketing::GetRadiusForStartEndElevation( void) const
 bool
 Pocketing::GetMidOfLongestOpenSide( const ICurveComposite* pCompo, Point3d& ptMid, Vector3d& vtMidOrt)
 {
+  // recupero il vettore estrusione
+   Vector3d vtExtr = Z_AX ;
+   pCompo->GetExtrusion( vtExtr) ;
   // richiedo lunghezza superiore a diametro utensile pił doppio offset radiale
    double dMaxLen = m_TParams.m_dDiam + 2 * GetOffsR() - EPS_SMALL ;
   // ciclo sulle singole curve
@@ -3701,8 +3704,9 @@ Pocketing::GetMidOfLongestOpenSide( const ICurveComposite* pCompo, Point3d& ptMi
          if ( pCrv->GetLength( dLen)  &&  dLen > dMaxLen) {
             dMaxLen = dLen ;
             pCrv->GetMidPoint( ptMid) ;
+           // vettore ortogonale verso l'esterno (ruotato -90deg rispetto a estrusione9
             pCrv->GetMidDir( vtMidOrt) ;
-            vtMidOrt.Rotate( Z_AX, 0, -1) ;
+            vtMidOrt.Rotate( vtExtr, 0, -1) ;
             bFound = true ;
          }
       }