diff --git a/WaterJetting.cpp b/WaterJetting.cpp
index 25ef9cc..fc9cca7 100644
--- a/WaterJetting.cpp
+++ b/WaterJetting.cpp
@@ -1311,17 +1311,27 @@ WaterJetting::ProcessPath( int nPathId, int nPvId, int nClId)
    double dThick ;
    pCompo->GetThickness( dThick) ;
 
-  // se percorso chiuso con inizio/fine su angolo interno, porto la partenza a metą del primo lato
+  // se percorso chiuso con lavorazione all'interno, porto la partenza a metą del lato pił lungo
    if ( pCompo->IsClosed()) {
-      Vector3d vtStart, vtEnd ;
-      pCompo->GetStartDir( vtStart) ;
-      pCompo->GetEndDir( vtEnd) ;
-      if ( ! AreSameVectorApprox( vtStart, vtEnd)) {
-         bool bAngCCW = ( ( vtEnd ^ vtStart) * vtTool > 0.0) ;
-         if ( m_Params.m_nWorkSide == WJET_WS_CENTER  ||
-              ( m_Params.m_nWorkSide == WJET_WS_RIGHT  &&  ! bAngCCW)  ||
-              ( m_Params.m_nWorkSide == WJET_WS_LEFT  &&  bAngCCW))
-            pCompo->ChangeStartPoint( 0.5) ;
+      double dArea ;
+      if ( pCompo->GetAreaXY( dArea)  &&
+           ( ( dArea < 0  &&  m_Params.m_nWorkSide == WJET_WS_RIGHT) ||
+             ( dArea > 0  &&  m_Params.m_nWorkSide == WJET_WS_LEFT))) {
+         int i = 0 ;
+         int nMax = - 1 ;
+         double dLenMax = 0 ;
+         const ICurve* pCrv = pCompo->GetFirstCurve() ;
+         while ( pCrv != nullptr) {
+            double dLen ;
+            if ( pCrv->GetLength( dLen)  &&  dLen > dLenMax) {
+               dLenMax = dLen ;
+               nMax = i ;
+            }
+            ++ i ;
+            pCrv = pCompo->GetNextCurve() ;
+         }
+         if ( nMax >= 0)
+            pCompo->ChangeStartPoint( nMax + 0.5) ;
       }
    }