diff --git a/SurfFinishing.cpp b/SurfFinishing.cpp
index 153c117..8ea730d 100644
--- a/SurfFinishing.cpp
+++ b/SurfFinishing.cpp
@@ -3666,7 +3666,7 @@ SurfFinishing::AddOptimal( ICAvToolSurfTm* pCAvTlStm, const SURFLOCALVECTOR& vSr
          if ( IsNull( pSfrToWork)  ||  ! pSfrToWork->IsValid())
             return false ;
         // Offset
-         if ( ! pSfrToWork->Offset( dPockRadOffs, ICurve::OFF_FILLET))
+         if ( ! pSfrToWork->Offset( dPockRadOffs + m_Params.m_dSideStep, ICurve::OFF_FILLET))
             return false ;
         // imposto i lati chiusi
          for ( int nCC = 0 ; nCC < pSfrToWork->GetChunkCount() ; ++ nCC) {
@@ -3746,8 +3746,12 @@ SurfFinishing::AddOptimal( ICAvToolSurfTm* pCAvTlStm, const SURFLOCALVECTOR& vSr
 
   // ----------------------- Lavorazione Zconst -------------------------------
    if ( ! IsNull( pSfrZConst)  &&  pSfrZConst->IsValid()) {
+     // recupero dai parametri eventuale Offset di sovrapposizione per ZConst
+      double dZConstOverlap = m_TParams.m_dDiam / 2 ;
+      if ( FromString( ExtractInfo( m_Params.m_sUserNotes, "ZConstOverlap="), dZConstOverlap))
+         dZConstOverlap = Clamp( dZConstOverlap, 0., m_TParams.m_dDiam / 2) ;
      // mi assicuro di non uscire dalla superficie originale
-      pSfrZConst->Offset( m_Params.m_dSideStep, ICurve::OFF_FILLET) ;
+      pSfrZConst->Offset( m_Params.m_dSideStep + dZConstOverlap, ICurve::OFF_FILLET) ;
       pSfrZConst->Intersect( *pSfr) ;
      // lavoro ogni singolo Chunk singolarmente ( non estendo lati aperti per eveitare merge con gli stessi Chunks)
       for ( int nC = 0 ; nC < pSfrZConst->GetChunkCount() ; ++ nC) {
@@ -4013,8 +4017,8 @@ SurfFinishing::AddProjection( ICAvToolSurfTm* pCAvTlStm, const SURFLOCALVECTOR&
 
   // definisco variabili globali
    BBox3d BBox3Loc ;                // box totale delle superici rispetto a frLoc
-   CISURFTMPVECTOR vpStm ;          // superfici TriMesh selezionate in globale
-   ICRVCOMPOPVECTOR vCrvToProj ;    // vettore delle curve da proiettare sulla superfcie
+   ISURFTMPOVECTOR vpStm ;          // superfici TriMesh selezionate in globale
+   ICRVCOMPOPOVECTOR vCrvToProj ;   // vettore delle curve da proiettare sulla superficie
 
   // scorro il vettore di superfici selezionate
    for ( int i = 0 ; i < int( vSrfLoc.size()) ; ++ i) {
@@ -4037,8 +4041,11 @@ SurfFinishing::AddProjection( ICAvToolSurfTm* pCAvTlStm, const SURFLOCALVECTOR&
    if ( bSkipMaxDown) {
      // definisco i dati di calcolo della Silhouette
       const double SILH_TOL = 1.0 ;
+      CISURFTMPVECTOR vSurf ; vSurf.reserve( vpStm.size()) ;
+      for ( int i = 0; i < int( vpStm.size()) ; ++ i)
+         vSurf.emplace_back( vpStm[i]) ;
       PtrOwner<ICAvParSilhouettesSurfTm> pCavParSilh( CreateCAvParSilhouettesSurfTm()) ;
-      if ( IsNull( pCavParSilh)  ||  ! pCavParSilh->SetData( vpStm, frLoc, SILH_TOL))
+      if ( IsNull( pCavParSilh)  ||  ! pCavParSilh->SetData( vSurf, frLoc, SILH_TOL))
          return false ;
       // recupero il vettore di PolyLine della silhouette
       POLYLINEVECTOR vPL ;
diff --git a/SurfRoughing.cpp b/SurfRoughing.cpp
index acce904..5178971 100644
--- a/SurfRoughing.cpp
+++ b/SurfRoughing.cpp
@@ -2053,7 +2053,7 @@ ISurfFlatRegion*
 SurfRoughing::GetSfrByStmIntersection( const IntersParPlanesSurfTm& IPPStm, double dDist, double dSmallOffs) const
 {
   // interseco la superficie alla quota corrente
-   PNTVECTOR vPnt ; 
+   PNTVECTOR vPnt ;
    BIPNTVECTOR vBpt ;
    TRIA3DVECTOR vTria ;
    if ( ! IPPStm.GetInters( dDist, vPnt, vBpt, vTria))
@@ -2064,7 +2064,7 @@ SurfRoughing::GetSfrByStmIntersection( const IntersParPlanesSurfTm& IPPStm, doub
       return CreateSurfFlatRegion() ;
 
   // definisco la tolleranza per i concatenamenti
-   double dToler = EPS_SMALL ;
+   double dToler = 10 * EPS_SMALL ;
 
   // costruisco la FlatRegion da ritornare
    SurfFlatRegionByContours SfrByC ;
@@ -2109,10 +2109,8 @@ SurfRoughing::GetSfrByStmIntersection( const IntersParPlanesSurfTm& IPPStm, doub
          continue ;
      // se curva chiusa entro 5 volte la tolleranza ma considerata aperta, la chiudo bene
       Point3d ptStart, ptEnd ;
-      if ( pCrvCompo->GetStartPoint( ptStart)  &&
-         pCrvCompo->GetEndPoint( ptEnd)  &&
-         AreSamePointEpsilon( ptStart, ptEnd, 5. * dToler)  &&
-         ! AreSamePointApprox( ptStart, ptEnd)) {
+      if ( pCrvCompo->GetStartPoint( ptStart)  &&  pCrvCompo->GetEndPoint( ptEnd)  &&
+           AreSamePointEpsilon( ptStart, ptEnd, 5. * dToler)  &&  ! AreSamePointApprox( ptStart, ptEnd)) {
          // porto il punto finale a coincidere esattamente con l'inizio
          pCrvCompo->ModifyEnd( ptStart) ;
       }