diff --git a/OffsetCurve3d.cpp b/OffsetCurve3d.cpp
index e5212c5..d13a226 100644
--- a/OffsetCurve3d.cpp
+++ b/OffsetCurve3d.cpp
@@ -258,6 +258,7 @@ OffsetCurve3d::Make( const PolyLine& PL, const VCT3DVECTOR& vOffDir, double dOff
             vOffsetCrvs[vEditInfo[i].nId].pCrv->ModifyStart( vEditInfo[i].ptStart) ;
          if ( vEditInfo[i].ptEnd.IsValid())
             vOffsetCrvs[vEditInfo[i].nId].pCrv->ModifyEnd( vEditInfo[i].ptEnd) ;
+         vOffsetCrvs[vEditInfo[i].nId].nParent = -2 ;
       }
    }
 
@@ -279,7 +280,9 @@ OffsetCurve3d::Make( const PolyLine& PL, const VCT3DVECTOR& vOffDir, double dOff
    #if SAVEOFFSET
       for ( int i = 0 ; i < ssize( vOffsetCrvs) ; ++i) {
          vGeo.push_back( vOffsetCrvs[i].pCrv->Clone()) ;
-         if ( vOffsetCrvs[i].nFlag == OffsetCurve3d::AngType::ANG_SMOOTH_CONC)
+         if ( vOffsetCrvs[i].nParent == -2)
+            vCol.push_back( LIME) ;
+         else if ( vOffsetCrvs[i].nFlag == OffsetCurve3d::AngType::ANG_SMOOTH_CONC)
             vCol.push_back( GREEN) ;
          else if ( vOffsetCrvs[i].nFlag == OffsetCurve3d::AngType::ANG_STR)
             vCol.push_back( PURPLE) ;
@@ -408,6 +411,7 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
             Point3d ptStart, ptEnd ;
             pSubCrv->GetStartPoint( ptStart) ;
             pSubCrv->GetEndPoint( ptEnd) ;
+            ////////// cilindri con asse sul parent
             Vector3d vtHeight = ptEnd - ptStart ;
             double dHeight = vtHeight.Len() ;
             vtHeight.Normalize() ;
@@ -418,13 +422,30 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
             vGeo.push_back( pSurfTm) ;
             vCol.push_back( LGRAY) ;
 #endif
+
+//            //// cilindri con la direz offset
+//            Point3d ptOffEnd ; vOffsetCrvs[vLines[j]].pCrv->GetEndPoint( ptOffEnd) ;
+//            Vector3d vtOff = ptOffEnd - ptEnd ; vtOff.Normalize() ;
+//            Vector3d vtHeight = ptEnd - ptStart ;
+//            double dHeight = vtHeight.Len() ;
+//            Vector3d vtNewAxis = OrthoCompo( vtHeight, vtOff) ;
+//            vtHeight.Normalize() ;
+//            vtNewAxis.Normalize() ;
+//            Point3d ptStartCyl = ptEnd -vtNewAxis * dHeight ;
+//            vCyl.emplace_back( ptStartCyl, vtNewAxis, dHeight, dRad, dLinTol) ;
+//#if SAVECYL
+//            CurveArc ca ; ca.Set( vCyl.back().frCyl.Orig(), vCyl.back().frCyl.VersZ(), dRad) ;
+//            ISurfTriMesh* pSurfTm = GetSurfTriMeshByExtrusion( &ca, vCyl.back().frCyl.VersZ() * dHeight, false, 2 * EPS_SMALL) ;
+//            vGeo.push_back( pSurfTm) ;
+//            vCol.push_back( LGRAY) ;
+//#endif
          }
 
          // controllo l'end di ogni linea per verificare se sta nel cilindro definito da uno degli altri tratti
          // controllo tutto i punti
          bool bErasedSomePart = false ;
          bool bCheckStart = false ;
-         INTVECTOR vInters ;
+         INTINTVECTOR vInters ;
          for ( int j = 0 ; j < ssize( vLines) ; ++j) {
             Point3d ptStart, ptEnd ;
             const ICurve* pSubCrv = vOffsetCrvs[vLines[j]].pCrv ;
@@ -448,16 +469,18 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
                   if ( ! bStartInsideCyl)
                      bCheckStart = true ;
                   // se avevo un'interruzione nella zona da modificare, la colmo
-                  if ( ! vInters.empty()  && vInters.back() != vLines[j-1]) {
+                  if ( ! vInters.empty()  && vInters.back().first != vLines[j-1]) {
                      // aggiungo tutti i precedenti che mancano
-                     for ( int h = vInters.back() + 1 ; h < vLines[j] ; ++h) {
-                        vInters.push_back( h) ;
+                     int z = vInters.back().second ;
+                     for ( int h = vInters.back().first + 1 ; h < vLines[j] ; ++h) {
+                        vInters.emplace_back( h, z) ;
                         vEditInfo.pop_back() ;
+                        ++z ;
                      }
                   }
-                  vInters.push_back( vLines[j]) ;
+                  vInters.emplace_back( vLines[j], j) ;
                   if ( ! bStartInsideCyl  &&  j < ssize( vLines) - 1) {
-                     vInters.push_back( vLines[j+1]) ;
+                     vInters.emplace_back( vLines[j+1], j + 1) ;
                      ++j ;
                   }
                   break ;
@@ -472,24 +495,24 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
             // calcolo le intersezioni effettive del primo e ultimo tratto cancellati con i cilindri che li hanno cancellati
             // controllo che effettivamente tutti i tratti cancellati siano consecutivi
             for ( int j = 1 ; j < ssize( vInters) ; ++j) {
-               if ( vInters[j] != vInters[j-1] + 1)
+               if ( vInters[j].first != vInters[j-1].first + 1)
                   return false ;
             }
             for ( int j = 0 ; j < ssize( vInters) ; ++j) {
                // cancello i tratti intermedi
                if ( j > 0 && j < ssize( vInters) - 1) {
-                  vEditInfo.emplace_back( vInters[j], EditCrvInfo::DEL) ;
+                  vEditInfo.emplace_back( vInters[j].first, EditCrvInfo::DEL) ;
                   continue ;
                }
                // per il primo e ultimo controllo le intersezioni con tutti i cilindri
-               PtrOwner<ICurve> pCL ( vOffsetCrvs[vInters[j]].pCrv->Clone()) ;
+               PtrOwner<ICurve> pCL ( vOffsetCrvs[vInters[j].first].pCrv->Clone()) ;
                Point3d ptStart ; pCL->GetStartPoint( ptStart) ;
                Vector3d vtStart ; pCL->GetStartDir( vtStart) ;
                double dLen ; pCL->GetLength( dLen) ;
                double dUTrim = ( j == 0 ? INFINITO : 0) ;
                Point3d ptTrim = P_INVALID ;
                for ( int k = 0 ; k < ssize( vCyl) ; ++k) {
-                  if ( vInters[j] == k)
+                  if ( vInters[j].second == k)
                      continue ;
                   Point3d ptInt1 = P_INVALID, ptInt2 = P_INVALID ;
                   double dU1, dU2 ;
@@ -513,11 +536,13 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
                }
                if ( j == 0) {
                   if ( ptTrim.IsValid()) {
-                     pCL->ModifyEnd( ptTrim) ;
-                     double dNewLen ; pCL->GetLength( dNewLen) ;
-                     if ( dNewLen < 0.1  &&  vInters[0] != 0) {  // se fosse il primo allora potrei modificare il successivo
-                        int nPrev = vInters[0] - 1 ;
-                        vInters[0] = nPrev ;
+                     bool bOk = pCL->ModifyEnd( ptTrim) ;
+                     double dNewLen ;
+                     if ( bOk)
+                        pCL->GetLength( dNewLen) ;
+                     if ( ( ! bOk  || dNewLen < 0.1)  &&  vInters[0].first != 0) {  // se fosse il primo allora potrei modificare il successivo
+                        int nPrev = vInters[0].first - 1 ;
+                        vInters[0].first = nPrev ;
                         int c = 1 ;
                         while( vEditInfo.end()[-c].nId != nPrev)
                            ++c ;
@@ -526,18 +551,20 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
                         vEditInfo.emplace_back( nPrev + 1, EditCrvInfo::DEL) ;
                      }
                      else
-                        vEditInfo.emplace_back( vInters[0], EditCrvInfo::EDIT, P_INVALID, ptTrim) ;
+                        vEditInfo.emplace_back( vInters[0].first, EditCrvInfo::EDIT, P_INVALID, ptTrim) ;
                   }
                   else
-                     vEditInfo.emplace_back( vInters[0], EditCrvInfo::EDIT, P_INVALID, P_INVALID) ;
+                     vEditInfo.emplace_back( vInters[0].first, EditCrvInfo::EDIT, P_INVALID, P_INVALID) ;
                }
                else {
                   if ( ptTrim.IsValid()) {
-                     pCL->ModifyStart( ptTrim) ;
-                     double dNewLen ; pCL->GetLength( dNewLen) ;
-                     if ( dNewLen < 0.1  &&  vInters[j] != ssize( vOffsetCrvs) - 1) {  // se fosse l'ultima curva allora potrei modificare la precedente
-                        int nNext = vInters[j] + 1 ;
-                        vInters[j] = nNext ;
+                     bool bOk = pCL->ModifyStart( ptTrim) ;
+                     double dNewLen ;
+                     if ( bOk)
+                        pCL->GetLength( dNewLen) ;
+                     if ( ( ! bOk  ||  dNewLen < 0.1)  &&  vInters[j].first != ssize( vOffsetCrvs) - 1) {  // se fosse l'ultima curva allora potrei modificare la precedente
+                        int nNext = vInters[j].first + 1 ;
+                        vInters[j].first = nNext ;
                         vEditInfo.emplace_back( nNext - 1, EditCrvInfo::DEL) ;
                         int c = 1 ;
                         while ( vEditInfo.end()[-c].nId != nNext  && c < ssize( vEditInfo))
@@ -550,10 +577,10 @@ CalcAdjustConcavePartsInPath( const ICurveComposite* pCrv, const OFFSETSEGVEC& v
                            vEditInfo.emplace_back( nNext, EditCrvInfo::EDIT, ptTrim, P_INVALID) ;
                      }
                      else
-                        vEditInfo.emplace_back( vInters[j], EditCrvInfo::EDIT, ptTrim, P_INVALID) ;
+                        vEditInfo.emplace_back( vInters[j].first, EditCrvInfo::EDIT, ptTrim, P_INVALID) ;
                   }
                   else
-                     vEditInfo.emplace_back( vInters[j], EditCrvInfo::EDIT, P_INVALID, P_INVALID) ;
+                     vEditInfo.emplace_back( vInters[j].first, EditCrvInfo::EDIT, P_INVALID, P_INVALID) ;
                }
             }
          }