diff --git a/CurveArc.cpp b/CurveArc.cpp
index 93d3af7..1afeac8 100644
--- a/CurveArc.cpp
+++ b/CurveArc.cpp
@@ -607,7 +607,7 @@ CurveArc::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-CurveArc::GetLocalBBox( BBox3d& b3Loc) const
+CurveArc::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -625,7 +625,7 @@ CurveArc::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-CurveArc::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+CurveArc::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
diff --git a/CurveArc.h b/CurveArc.h
index d840226..80bd870 100644
--- a/CurveArc.h
+++ b/CurveArc.h
@@ -30,8 +30,8 @@ class CurveArc : public ICurveArc, public IGeoObjRW
                       { return ( m_nStatus == OK) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/CurveBezier.cpp b/CurveBezier.cpp
index 4bd4a64..21c188e 100644
--- a/CurveBezier.cpp
+++ b/CurveBezier.cpp
@@ -471,21 +471,37 @@ CurveBezier::Validate( void)
 
 //----------------------------------------------------------------------------
 bool
-CurveBezier::GetLocalBBox( BBox3d& b3Loc) const
+CurveBezier::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
       return false ;
   // assegno il box in locale
    b3Loc.Reset() ;
-   for ( int i = 0 ; i <= m_nDeg ; ++ i)
-      b3Loc.Add( m_aPtCtrl[i]) ;
+   // basta approssimato
+   if ( ( nFlag & BBF_EXACT) == 0) {
+      for ( int i = 0 ; i <= m_nDeg ; ++ i)
+         b3Loc.Add( m_aPtCtrl[i]) ;
+   }
+   // deve essere preciso
+   else {
+     // costruisco una approssimazione lineare
+      PolyLine PL ;
+      if ( ! ApproxWithLines( LIN_TOL_STD, ANG_TOL_STD_DEG, PL))
+         return false ;
+     // ciclo sui punti della approssimazione
+      Point3d  ptTemp ;
+      for ( bool bFound = PL.GetFirstPoint( ptTemp) ; bFound ; bFound = PL.GetNextPoint( ptTemp)) {
+         b3Loc.Add( ptTemp) ;
+      }
+   }
+
    return true ;
 }
 
 //----------------------------------------------------------------------------
 bool
-CurveBezier::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+CurveBezier::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -495,10 +511,26 @@ CurveBezier::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
       return false ;
   // assegno il box nel riferimento
    b3Ref.Reset() ;
-   for ( int i = 0 ; i <= m_nDeg ; ++ i) {
-      Point3d ptTemp = m_aPtCtrl[i] ;
-      ptTemp.ToGlob( frRef) ;
-      b3Ref.Add( ptTemp) ;
+   // basta approssimato
+   if ( ( nFlag & BBF_EXACT) == 0) {
+      for ( int i = 0 ; i <= m_nDeg ; ++ i) {
+         Point3d ptTemp = m_aPtCtrl[i] ;
+         ptTemp.ToGlob( frRef) ;
+         b3Ref.Add( ptTemp) ;
+      }
+   }
+   // deve essere preciso
+   else {
+     // costruisco una approssimazione lineare
+      PolyLine PL ;
+      if ( ! ApproxWithLines( LIN_TOL_STD, ANG_TOL_STD_DEG, PL))
+         return false ;
+     // ciclo sui punti della approssimazione
+      Point3d  ptTemp ;
+      for ( bool bFound = PL.GetFirstPoint( ptTemp) ; bFound ; bFound = PL.GetNextPoint( ptTemp)) {
+         ptTemp.ToGlob( frRef) ;
+         b3Ref.Add( ptTemp) ;
+      }
    }
 
    return true ;
diff --git a/CurveBezier.h b/CurveBezier.h
index 648e3ec..ac671a1 100644
--- a/CurveBezier.h
+++ b/CurveBezier.h
@@ -32,8 +32,8 @@ class CurveBezier : public ICurveBezier, public IGeoObjRW
                       { return ( m_nStatus == OK) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/CurveComposite.cpp b/CurveComposite.cpp
index 271f52c..0b763db 100644
--- a/CurveComposite.cpp
+++ b/CurveComposite.cpp
@@ -646,7 +646,7 @@ CurveComposite::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-CurveComposite::GetLocalBBox( BBox3d& b3Loc) const
+CurveComposite::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -659,7 +659,7 @@ CurveComposite::GetLocalBBox( BBox3d& b3Loc) const
    while ( pCrvSmpl != nullptr) {
       BBox3d b3Crv ;
      // recupero il box della curva
-      pCrvSmpl->GetLocalBBox( b3Crv) ;
+      pCrvSmpl->GetLocalBBox( b3Crv, nFlag) ;
      // aggiorno il box
       b3Loc.Add( b3Crv) ;
      // passo alla curva successiva
@@ -670,7 +670,7 @@ CurveComposite::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-CurveComposite::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+CurveComposite::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -686,7 +686,7 @@ CurveComposite::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
    while ( pCrvSmpl != nullptr) {
       BBox3d b3Crv ;
      // recupero il box della curva
-      pCrvSmpl->GetBBox( frRef, b3Crv) ;
+      pCrvSmpl->GetBBox( frRef, b3Crv, nFlag) ;
      // aggiorno il box
       b3Ref.Add( b3Crv) ;
      // passo alla curva successiva
diff --git a/CurveComposite.h b/CurveComposite.h
index b460148..9399f53 100644
--- a/CurveComposite.h
+++ b/CurveComposite.h
@@ -32,8 +32,8 @@ class CurveComposite : public ICurveComposite, public IGeoObjRW
                       { return ( m_nStatus == OK) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/CurveLine.cpp b/CurveLine.cpp
index 72831e5..cdaf48e 100644
--- a/CurveLine.cpp
+++ b/CurveLine.cpp
@@ -202,7 +202,7 @@ CurveLine::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-CurveLine::GetLocalBBox( BBox3d& b3Loc) const
+CurveLine::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -214,7 +214,7 @@ CurveLine::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-CurveLine::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+CurveLine::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
diff --git a/CurveLine.h b/CurveLine.h
index a097d2b..6d47b3b 100644
--- a/CurveLine.h
+++ b/CurveLine.h
@@ -30,8 +30,8 @@ class CurveLine : public ICurveLine, public IGeoObjRW
                       { return ( m_nStatus == OK) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index f23d6bf..2a7a67c 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/ExtText.cpp b/ExtText.cpp
index 0ced4db..3784336 100644
--- a/ExtText.cpp
+++ b/ExtText.cpp
@@ -327,7 +327,7 @@ ExtText::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-ExtText::GetLocalBBox( BBox3d& b3Loc) const
+ExtText::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // recupero il font manager
    FontManager& fntMgr = FontManager::GetFontManager() ;
@@ -351,7 +351,7 @@ ExtText::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-ExtText::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+ExtText::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico validità del frame
    if ( frRef.GetType() == Frame3d::ERR)
diff --git a/ExtText.h b/ExtText.h
index 4c1d723..09d0eaa 100644
--- a/ExtText.h
+++ b/ExtText.h
@@ -30,8 +30,8 @@ class ExtText : public IExtText, public IGeoObjRW
                 { return true ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/GdbGeo.cpp b/GdbGeo.cpp
index 72f696f..22d7998 100644
--- a/GdbGeo.cpp
+++ b/GdbGeo.cpp
@@ -186,7 +186,7 @@ GdbGeo::GetLocalBBox( BBox3d& b3Loc, int nFlag, int nLev) const
       }
    }
 
-   return m_pGeoObj->GetLocalBBox( b3Loc) ;
+   return m_pGeoObj->GetLocalBBox( b3Loc, nFlag) ;
 }
 
 //----------------------------------------------------------------------------
@@ -225,7 +225,7 @@ GdbGeo::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag, int nLev) const
       }
    }
 
-   return m_pGeoObj->GetBBox( frRef, b3Ref) ;
+   return m_pGeoObj->GetBBox( frRef, b3Ref, nFlag) ;
 }
 
 //----------------------------------------------------------------------------
diff --git a/GdbIterator.h b/GdbIterator.h
index 4b5032a..104f8fa 100644
--- a/GdbIterator.h
+++ b/GdbIterator.h
@@ -45,9 +45,9 @@ class GdbIterator : public IGdbIterator
       virtual int  GetId( void) const ;
       virtual int  GetParentId( void) const ;
       virtual bool GetGlobFrame( Frame3d& frGlob) const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_NONE) const ;
-      virtual bool GetGlobalBBox( BBox3d& b3Glob, int nFlag = BBF_NONE) const ;
-      virtual bool GetRefBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_NONE) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetGlobalBBox( BBox3d& b3Glob, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetRefBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool SetLevel( int nLevel) ;
       virtual bool RevertLevel( void) ;
       virtual bool GetLevel( int& nLevel) const ;
diff --git a/GeoFrame3d.cpp b/GeoFrame3d.cpp
index bfac39b..21eaec0 100644
--- a/GeoFrame3d.cpp
+++ b/GeoFrame3d.cpp
@@ -170,7 +170,7 @@ GeoFrame3d::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-GeoFrame3d::GetLocalBBox( BBox3d& b3Loc) const
+GeoFrame3d::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // assegno il box in locale (considero l'origine)
    b3Loc.Set( m_frF.Orig()) ;
@@ -179,7 +179,7 @@ GeoFrame3d::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-GeoFrame3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+GeoFrame3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico validità del frame
    if ( frRef.GetType() == Frame3d::ERR)
diff --git a/GeoFrame3d.h b/GeoFrame3d.h
index ad69726..93c2101 100644
--- a/GeoFrame3d.h
+++ b/GeoFrame3d.h
@@ -30,8 +30,8 @@ class GeoFrame3d : public IGeoFrame3d, public IGeoObjRW
                 { return ( m_frF.GetType() != Frame3d::ERR) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool GetFrame( Frame3d& frF) const
                 { frF = m_frF ; return true ;}
       virtual bool Translate( const Vector3d& vtMove)
diff --git a/GeoPoint3d.cpp b/GeoPoint3d.cpp
index 0e4c952..cf77c64 100644
--- a/GeoPoint3d.cpp
+++ b/GeoPoint3d.cpp
@@ -136,7 +136,7 @@ GeoPoint3d::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-GeoPoint3d::GetLocalBBox( BBox3d& b3Loc) const
+GeoPoint3d::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // assegno il box in locale
    b3Loc.Set( m_ptP) ;
@@ -145,7 +145,7 @@ GeoPoint3d::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-GeoPoint3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+GeoPoint3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico validità del frame
    if ( frRef.GetType() == Frame3d::ERR)
diff --git a/GeoPoint3d.h b/GeoPoint3d.h
index daa03b1..350189b 100644
--- a/GeoPoint3d.h
+++ b/GeoPoint3d.h
@@ -30,8 +30,8 @@ class GeoPoint3d : public IGeoPoint3d, public IGeoObjRW
                 { return true ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove)
                 { m_OGrMgr.Reset() ; m_ptP.Translate( vtMove) ; return true ; }
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
diff --git a/GeoVector3d.cpp b/GeoVector3d.cpp
index 6cf4c4e..9eea141 100644
--- a/GeoVector3d.cpp
+++ b/GeoVector3d.cpp
@@ -162,7 +162,7 @@ GeoVector3d::Load( NgeReader& ngeIn)
 
 //----------------------------------------------------------------------------
 bool
-GeoVector3d::GetLocalBBox( BBox3d& b3Loc) const
+GeoVector3d::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // il box tiene conto della posizione della base e del tip
    b3Loc.Set( m_ptBase, m_ptBase + m_vtV) ;
@@ -171,7 +171,7 @@ GeoVector3d::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-GeoVector3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+GeoVector3d::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico validità del frame
    if ( frRef.GetType() == Frame3d::ERR)
diff --git a/GeoVector3d.h b/GeoVector3d.h
index c4f6644..b36d74e 100644
--- a/GeoVector3d.h
+++ b/GeoVector3d.h
@@ -29,8 +29,8 @@ class GeoVector3d : public IGeoVector3d, public IGeoObjRW
                 { return true ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove)
                 { m_OGrMgr.Reset() ; m_ptBase.Translate( vtMove) ; return true ; }
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
diff --git a/GeomDB.h b/GeomDB.h
index a23ea6f..94757bc 100644
--- a/GeomDB.h
+++ b/GeomDB.h
@@ -53,9 +53,9 @@ class GeomDB : public IGeomDB
       virtual int  GetParentId( int nId) const ;
       virtual bool GetGlobFrame( int nId, Frame3d& frGlob) const
                       { return GetGroupGlobFrame( GetParentId( nId), frGlob) ; }
-      virtual bool GetLocalBBox( int nId, BBox3d& b3Loc, int nFlag = BBF_NONE) const ;
-      virtual bool GetGlobalBBox( int nId, BBox3d& b3Glob, int nFlag = BBF_NONE) const ;
-      virtual bool GetRefBBox( int nId, const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_NONE) const ;
+      virtual bool GetLocalBBox( int nId, BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetGlobalBBox( int nId, BBox3d& b3Glob, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetRefBBox( int nId, const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual int  Copy( int nIdSou, int nIdDest, int nRefId, int nSonBeforeAfter = GDB_SON)
                       { return Copy( nIdSou, nIdDest, nRefId, nSonBeforeAfter, false) ; }
       virtual int  CopyGlob( int nIdSou, int nIdDest, int nRefId, int nSonBeforeAfter = GDB_SON)
diff --git a/SurfTriMesh.cpp b/SurfTriMesh.cpp
index 5b99d7f..f493827 100644
--- a/SurfTriMesh.cpp
+++ b/SurfTriMesh.cpp
@@ -1612,7 +1612,7 @@ SurfTriMesh::DoSewing( const ISurfTriMesh& stmOther, const Frame3d& frOther)
 
 //----------------------------------------------------------------------------
 bool
-SurfTriMesh::GetLocalBBox( BBox3d& b3Loc) const
+SurfTriMesh::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
@@ -1628,7 +1628,7 @@ SurfTriMesh::GetLocalBBox( BBox3d& b3Loc) const
 
 //----------------------------------------------------------------------------
 bool
-SurfTriMesh::GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const
+SurfTriMesh::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
 {
   // verifico lo stato
    if ( m_nStatus != OK)
diff --git a/SurfTriMesh.h b/SurfTriMesh.h
index f59b091..a26a344 100644
--- a/SurfTriMesh.h
+++ b/SurfTriMesh.h
@@ -65,8 +65,8 @@ class SurfTriMesh : public ISurfTriMesh, public IGeoObjRW
                       { return ( m_nStatus == OK) ; }
       virtual const std::string& GetTitle( void) const ;
       virtual bool Dump( std::string& sOut, const char* szNewLine = "\n") const ;
-      virtual bool GetLocalBBox( BBox3d& b3Loc) const ;
-      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref) const ;
+      virtual bool GetLocalBBox( BBox3d& b3Loc, int nFlag = BBF_STANDARD) const ;
+      virtual bool GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag = BBF_STANDARD) const ;
       virtual bool Translate( const Vector3d& vtMove) ;
       virtual bool Rotate( const Point3d& ptAx, const Vector3d& vtAx, double dAngDeg)
                       { double dAngRad = dAngDeg * DEGTORAD ;
diff --git a/Vector3d.cpp b/Vector3d.cpp
index fae8910..55ea880 100644
--- a/Vector3d.cpp
+++ b/Vector3d.cpp
@@ -347,12 +347,10 @@ Vector3d::ToGlob( const Frame3d& frRef)
       return true ;
 
   // eseguo trasformazione
-   if ( frRef.GetType() != Frame3d::TOP) {
-      Vector3d vtT( x, y, z) ;
-      x = vtT.x * frRef.VersX().x + vtT.y * frRef.VersY().x + vtT.z * frRef.VersZ().x ;
-      y = vtT.x * frRef.VersX().y + vtT.y * frRef.VersY().y + vtT.z * frRef.VersZ().y ;
-      z = vtT.x * frRef.VersX().z + vtT.y * frRef.VersY().z + vtT.z * frRef.VersZ().z ;
-   }
+   Vector3d vtT( x, y, z) ;
+   x = vtT.x * frRef.VersX().x + vtT.y * frRef.VersY().x + vtT.z * frRef.VersZ().x ;
+   y = vtT.x * frRef.VersX().y + vtT.y * frRef.VersY().y + vtT.z * frRef.VersZ().y ;
+   z = vtT.x * frRef.VersX().z + vtT.y * frRef.VersY().z + vtT.z * frRef.VersZ().z ;
 
    return true ;
 }
@@ -372,12 +370,10 @@ Vector3d::ToLoc( const Frame3d& frRef)
       return true ;
 
   // eseguo trasformazione
-   if ( frRef.GetType() != Frame3d::TOP) {
-      Vector3d vtT( x, y, z) ;
-      x = vtT.x * frRef.VersX().x + vtT.y * frRef.VersX().y + vtT.z * frRef.VersX().z ;
-      y = vtT.x * frRef.VersY().x + vtT.y * frRef.VersY().y + vtT.z * frRef.VersY().z ;
-      z = vtT.x * frRef.VersZ().x + vtT.y * frRef.VersZ().y + vtT.z * frRef.VersZ().z ;
-   }
+   Vector3d vtT( x, y, z) ;
+   x = vtT.x * frRef.VersX().x + vtT.y * frRef.VersX().y + vtT.z * frRef.VersX().z ;
+   y = vtT.x * frRef.VersY().x + vtT.y * frRef.VersY().y + vtT.z * frRef.VersY().z ;
+   z = vtT.x * frRef.VersZ().x + vtT.y * frRef.VersZ().y + vtT.z * frRef.VersZ().z ;
 
    return true ;
 }