diff --git a/SurfRoughing.cpp b/SurfRoughing.cpp
index 777bc7f..ae7771c 100644
--- a/SurfRoughing.cpp
+++ b/SurfRoughing.cpp
@@ -1764,6 +1764,9 @@ SurfRoughing::CalcPaths( const INTINTVECTOR& vPocket, const ICRVCOMPOPOVECTOR& v
    for ( auto& vId : vPocket) {
 
      // recupero la superficie da lavorare
+      const ISurfFlatRegion* pSfrPock = GetSurfFlatRegion( m_pGeomDB->GetGeoObj( vId.first)) ;
+      if ( pSfrPock == nullptr  ||  ! pSfrPock->IsValid())
+         continue ;
       vStepInfo[nInd].pSfrPock.Set( CloneSurfFlatRegion( m_pGeomDB->GetGeoObj( vId.first))) ;
      // controllo se la regione è relativa ad uno step base o ad uno step intermedio
       vStepInfo[nInd].bIsSubStep = ( vStepInfo[nInd].pSfrPock->GetTempProp( 0) == 1) ;
@@ -1833,17 +1836,6 @@ SurfRoughing::CalcPaths( const INTINTVECTOR& vPocket, const ICRVCOMPOPOVECTOR& v
             return false ;
          }
       }
-     // se la svuotatura è di tipo conformal ZigZag ma la geometria non è valida
-      if ( nSubType == SURFROU_SUB_CONFORMAL_ZIGZAG  &&  vStepInfo[nInd].vPaths.empty()) {
-         if ( vStepInfo[nInd].bIsSubStep) {
-            string sWarn = "Warning in SurfRoughing : invalid Conformal ZigZag at substep (" + ToString( vStepInfo[nInd].dDepth, 1) + ")" ;
-            m_pMchMgr->SetWarning( 3056, sWarn) ;
-         }
-         else {
-            m_pMchMgr->SetLastError( 3030, "Error in SurfRoughing : Conformal ZigZag not valid at step (" + ToString( vStepInfo[nInd].dDepth, 1) + ")") ;
-            return false ;
-         }
-      }
      // se non ho ottenuto percorsi, allora passo allo step successivo ( nInd non viene aggiornato!)
       if ( vCrvPaths.empty())
          continue ;
@@ -2108,8 +2100,21 @@ SurfRoughing::AddPocket( const INTINTVECTOR& vPocket, const Vector3d& vtTool, co
                   dCurrElev = dSafeZ ;
                   double dNextElev = dSafeZ ;
                   if ( bSafe) {
-                     if ( bSamePlane  &&  ! vStepInfo[i].vPaths[j+1].bOutStart)
-                        dCurrElev -= currStep.dRelativeDepth ;
+                     /* Questo controllo serve se passando da un chunk all'altro si interseca un ulteriore
+                        Chunk non ancora svuotato; per ora non capita mai...
+                     */
+                     //if ( bSamePlane) {
+                     //   dCurrElev -= currStep.dRelativeDepth ;
+                     //   dNextElev = dCurrElev ;
+                     //}
+                     if ( bSamePlane) {
+                        if ( ( ( currStep.nSubType == SURFROU_SUB_SPIRALIN  ||  currStep.nSubType == SURFROU_SUB_SPIRALOUT) &&
+                               ! vStepInfo[i].vPaths[j+1].bOutStart)  ||
+                             ( currStep.nSubType != SURFROU_SUB_SPIRALIN  &&  currStep.nSubType != SURFROU_SUB_SPIRALOUT)) {
+                           dCurrElev -= currStep.dRelativeDepth ;
+                           dNextElev = dCurrElev ;
+                        }
+                     }
                      else if ( bNextIsBelow)
                         dNextElev += ( ptEnd - ptDest) * vtTool ;
                      else {
@@ -3143,7 +3148,7 @@ SurfRoughing::VerifyLeadInLeadOut( const ICurve* pCrv, const ICurveComposite* pC
       return false ;
 
   // calcolo la Fat Curve del tratto lineare e la porto in globale
-   PtrOwner<ISurfFlatRegion> pSfrFat( GetSurfFlatRegionFromFatCurve( pCrvLoc->Clone(), m_TParams.m_dDiam / 2, false, false)) ;
+   PtrOwner<ISurfFlatRegion> pSfrFat( GetSurfFlatRegionFromFatCurve( pCrvLoc->Clone(), m_TParams.m_dDiam / 2 - 50 * EPS_SMALL, false, false)) ;
    if ( IsNull( pSfrFat)  ||  ! pSfrFat->IsValid())
       return false ;