diff --git a/CurveComposite.cpp b/CurveComposite.cpp
index 023a7a2..558e229 100644
--- a/CurveComposite.cpp
+++ b/CurveComposite.cpp
@@ -2749,29 +2749,28 @@ CurveComposite::RemoveUndercutOnY( double dLinTol, double dAngTolDeg)
    double dYmin = b3Box.GetMin().y - DELTA_Y ;
    PtrOwner<ICurve> pCrv ;
    while ( pCrv.Set( ccCopy.RemoveFirstOrLastCurve( false))) {
-     // se linea verticale non sottende alcunché, quindi la salto
-      if ( pCrv->GetType() == CRV_LINE) {
-         const CurveLine* pLine = GetBasicCurveLine( pCrv) ;
-         if ( abs( pLine->GetStart().x - pLine->GetEnd().x) < EPS_SMALL) {
-            pCrv.Reset() ;
-            continue ;
-         }
-      }
      // creo la regione sottesa dalla curva
       PtrOwner<CurveComposite> pCompo( CreateBasicCurveComposite()) ;
       if ( IsNull( pCompo))
          return false ;
       pCompo->AddCurve( Release( pCrv)) ;
+     // estremi
       Point3d ptStart, ptEnd ;
       pCompo->GetStartPoint( ptStart) ;
       pCompo->GetEndPoint( ptEnd) ;
+     // se curva pressochè verticale non sottende alcunché, quindi la salto
+      if ( abs( ptStart.x - ptEnd.x) < EPS_SMALL)
+         continue ;
+     // ordino gli estremi
       if ( ptStart.x < ptEnd.x) {
          swap( ptStart, ptEnd) ;
          pCompo->Invert() ;
       }
+     // chiudo la curva
       pCompo->AddLine( Point3d( ptEnd.x, dYmin, ptEnd.z)) ;
       pCompo->AddLine( Point3d( ptStart.x, dYmin, ptStart.z)) ;
       pCompo->Close() ;
+     // creo regione sottesa
       SurfFlatRegion Sfr ;
       Sfr.AddExtLoop( Release( pCompo)) ;
       if ( ! Sfr.IsValid())
diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index e21fe9e..b1ef3ea 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ