diff --git a/CurveComposite.cpp b/CurveComposite.cpp
index c0ffe14..fd59aec 100644
--- a/CurveComposite.cpp
+++ b/CurveComposite.cpp
@@ -604,6 +604,10 @@ CurveComposite::CopyFrom( const CurveComposite& ccSrc)
       if ( ! AddCurve( *pCrv))
          return false ;
    }
+   if ( ccSrc.m_nStatus == IS_A_POINT) {
+      m_ptStart = ccSrc.m_ptStart ;
+      m_nStatus = IS_A_POINT ;
+   }
    return true ;
 }
 
diff --git a/SurfBezier.cpp b/SurfBezier.cpp
index b12274c..5987782 100644
--- a/SurfBezier.cpp
+++ b/SurfBezier.cpp
@@ -632,8 +632,21 @@ SurfBezier::CopyFrom( const SurfBezier& sbSrc)
       m_bTrimmed = true ;
       m_pTrimReg = sbSrc.m_pTrimReg->Clone() ;
    }
-   if ( sbSrc.m_pSTM != nullptr)
+   if ( sbSrc.m_pSTM != nullptr) {
       m_pSTM = sbSrc.m_pSTM->Clone() ;
+      for ( int i = 0 ; i < int( sbSrc.m_mCCEdge.size()) ; ++i) {
+         m_mCCEdge.emplace_back() ;
+         for ( int j = 0 ; j < int( sbSrc.m_mCCEdge[i].size()) ; ++j ) {
+            m_mCCEdge.back().emplace_back( sbSrc.m_mCCEdge[i][j]->Clone()) ;
+         }
+      }
+      if( sbSrc.m_bTrimmed) {
+         for ( int i = 0 ; i < int( sbSrc.m_vCCLoop.size()) ; ++i)
+            m_vCCLoop.emplace_back( sbSrc.m_vCCLoop[i]->Clone());
+      }
+   }
+   m_bClosedU = sbSrc.m_bClosedU ;
+   m_bClosedV = sbSrc.m_bClosedV ;
    m_nTempProp[0] = sbSrc.m_nTempProp[0] ;
    m_nTempProp[1] = sbSrc.m_nTempProp[1] ;
    m_dTempParam[0] = sbSrc.m_dTempParam[0] ;
@@ -1883,6 +1896,9 @@ SurfBezier::ResetAuxSurf( void) const
    if ( m_pSTM != nullptr)
       delete( m_pSTM) ;
    m_pSTM = nullptr ;
+
+   m_mCCEdge.clear() ;
+   m_vCCLoop.clear() ;
 }
 
 //----------------------------------------------------------------------------
@@ -1896,6 +1912,9 @@ SurfBezier::ResetTrimRegion( void)
    m_bTrimmed = false ;
    // imposto ricalcolo della grafica
    m_OGrMgr.Reset() ;
+
+   m_mCCEdge.clear() ;
+   m_vCCLoop.clear() ;
 }
 
 //----------------------------------------------------------------------------
@@ -2362,16 +2381,18 @@ SurfBezier::CreateTrimRegionFromCuts( ICRVCOMPOPOVECTOR& vpCCOpen, ICRVCOMPOPOVE
 
    // devo verificare se devo aggiungere anche il bordo ( basta verificare se il primo loop chiuso è CCW)
    double dArea ;
-   vpCCClosed[0]->GetAreaXY( dArea) ;
-   if ( dArea < EPS_SMALL ) {
-      PolyLine plEdge ;
-      plEdge.AddUPoint( 0, ORIG) ;
-      plEdge.AddUPoint( 1, Point3d( m_nSpanU * SBZ_TREG_COEFF, 0)) ;
-      plEdge.AddUPoint( 2, Point3d( m_nSpanU * SBZ_TREG_COEFF, m_nSpanV * SBZ_TREG_COEFF)) ;
-      plEdge.AddUPoint( 3, Point3d( 0, m_nSpanV * SBZ_TREG_COEFF)) ;
-      plEdge.Close() ;
-      vpCCClosed.emplace_back( CreateCurveComposite()) ;
-      vpCCClosed.back()->FromPolyLine( plEdge) ;
+   if( vpCCClosed.size() != 0) {
+      vpCCClosed[0]->GetAreaXY( dArea) ;
+      if ( dArea < EPS_SMALL ) {
+         PolyLine plEdge ;
+         plEdge.AddUPoint( 0, ORIG) ;
+         plEdge.AddUPoint( 1, Point3d( m_nSpanU * SBZ_TREG_COEFF, 0)) ;
+         plEdge.AddUPoint( 2, Point3d( m_nSpanU * SBZ_TREG_COEFF, m_nSpanV * SBZ_TREG_COEFF)) ;
+         plEdge.AddUPoint( 3, Point3d( 0, m_nSpanV * SBZ_TREG_COEFF)) ;
+         plEdge.Close() ;
+         vpCCClosed.emplace_back( CreateCurveComposite()) ;
+         vpCCClosed.back()->FromPolyLine( plEdge) ;
+      }
    }
 
    // aggiungo i loop chiusi
@@ -2610,7 +2631,8 @@ SurfBezier::UnprojectPointFromStm( int nT, const Point3d& ptI, Point3d& ptSP, in
       }
 
       // se ho tre intersezioni vuol dire che un lato è collassato in un punto e il punto di cui voglio la controimmagine è esattamente nel polo
-      if ( nInters == 3  ||  ( m_bClosedU &&  ( vInters[1] == 1 || vInters[3] == 1))  ||  ( m_bClosedV  &&  ( vInters[1] == 1  ||  vInters[3] == 1))) {
+      // oppure sono su un lato di chiusura
+      if ( nInters == 3  ||  ( m_bClosedU &&  ( vInters[1] == 1 || vInters[3] == 1))  ||  ( m_bClosedV  &&  ( vInters[0] == 1  ||  vInters[2] == 1))) {
          if ( nInters == 3)
             bIsPole = true ;
          // visto che sono in un polo o su un lato di chiusura devo verificare di aver ricevuto il triangolo giusto