diff --git a/CurveArc.h b/CurveArc.h
index 4120921..beb4920 100644
--- a/CurveArc.h
+++ b/CurveArc.h
@@ -44,6 +44,8 @@ class CurveArc : public ICurveArc
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :                      // ICurve
       virtual bool IsSimple( void) const { return true ; }
diff --git a/CurveBezier.h b/CurveBezier.h
index 71dca2e..af1478b 100644
--- a/CurveBezier.h
+++ b/CurveBezier.h
@@ -46,6 +46,8 @@ class CurveBezier : public ICurveBezier
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :                      // ICurve
       virtual bool IsSimple( void) const { return true ; }
diff --git a/CurveComposite.h b/CurveComposite.h
index af974a2..c281179 100644
--- a/CurveComposite.h
+++ b/CurveComposite.h
@@ -48,6 +48,8 @@ class CurveComposite : public ICurveComposite
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :                      // ICurve
       virtual bool IsSimple( void) const { return false ; }
diff --git a/CurveLine.h b/CurveLine.h
index 668659d..a34f7a8 100644
--- a/CurveLine.h
+++ b/CurveLine.h
@@ -44,6 +44,8 @@ class CurveLine : public ICurveLine
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :                      // ICurve
       virtual bool IsSimple( void) const { return true ; }
diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index 3737933..dd27193 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ
diff --git a/GdbIterator.cpp b/GdbIterator.cpp
index 75bfb89..e838e99 100644
--- a/GdbIterator.cpp
+++ b/GdbIterator.cpp
@@ -168,8 +168,8 @@ GdbIterator::GetGeoObj( void)
 }
 
 //----------------------------------------------------------------------------
-Frame3d*
-GdbIterator::GetGroupFrame( void)
+IGeoFrame3d*
+GdbIterator::GetGeoFrame( void)
 {
    GdbGroup* pGdbGroup ;
 
@@ -180,7 +180,25 @@ GdbIterator::GetGroupFrame( void)
    if ( ( pGdbGroup = GetGdbGroup( m_pCurrNode)) == nullptr)
       return nullptr ;
 
-   return &( pGdbGroup->m_gfrFrame.m_frF) ;
+   return &( pGdbGroup->m_gfrFrame) ;
+}
+
+//----------------------------------------------------------------------------
+bool
+GdbIterator::GetGroupFrame( Frame3d& frGlob)
+{
+   GdbGroup* pGdbGroup ;
+
+
+   if ( m_pGDB == nullptr  ||  m_pCurrNode == nullptr)
+      return false ;
+
+   if ( ( pGdbGroup = GetGdbGroup( m_pCurrNode)) == nullptr)
+      return false ;
+
+  // copio il riferimento
+   frGlob = pGdbGroup->m_gfrFrame.m_frF ;
+   return true ;
 }
 
 //----------------------------------------------------------------------------
diff --git a/GdbIterator.h b/GdbIterator.h
index e9ae60f..731c8a3 100644
--- a/GdbIterator.h
+++ b/GdbIterator.h
@@ -31,7 +31,8 @@ class GdbIterator : public IGdbIterator
 
       virtual GdbType GetGdbType( void) const ;
       virtual IGeoObj* GetGeoObj( void) ;
-      virtual Frame3d* GetGroupFrame( void) ;
+      virtual IGeoFrame3d* GetGeoFrame( void) ;
+      virtual bool GetGroupFrame( Frame3d& frGlob) ;
       virtual bool GetGroupGlobFrame( Frame3d& frGlob) ;
       virtual int  GetId( void) ;
       virtual int  GetParentId( void) ;
diff --git a/GeoFrame3d.h b/GeoFrame3d.h
index 7e0d2be..51a7da3 100644
--- a/GeoFrame3d.h
+++ b/GeoFrame3d.h
@@ -50,6 +50,8 @@ class GeoFrame3d : public IGeoFrame3d
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :                      // IGeoFrame3d
       virtual bool Set( const Point3d& ptOrig, const Vector3d& vtDirX, 
diff --git a/GeoPoint3d.h b/GeoPoint3d.h
index dd5d696..f5caed6 100644
--- a/GeoPoint3d.h
+++ b/GeoPoint3d.h
@@ -50,6 +50,8 @@ class GeoPoint3d : public IGeoPoint3d
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :
       virtual bool Set( const Point3d& ptP) ;
diff --git a/GeoVector3d.h b/GeoVector3d.h
index 1f77b23..1cbbf9a 100644
--- a/GeoVector3d.h
+++ b/GeoVector3d.h
@@ -50,6 +50,8 @@ class GeoVector3d : public IGeoVector3d
                       { m_OGrMgr.SetObjGraphics( pOGr) ; }
       virtual IObjGraphics* GetObjGraphics( void)
                       { return m_OGrMgr.GetObjGraphics() ; }
+      virtual const IObjGraphics* GetObjGraphics( void) const
+                      { return m_OGrMgr.GetObjGraphics() ; }
 
    public :
       virtual bool Set( const Vector3d& vtV) ;
diff --git a/ObjGraphicsMgr.h b/ObjGraphicsMgr.h
index 27d0813..2bbecb1 100644
--- a/ObjGraphicsMgr.h
+++ b/ObjGraphicsMgr.h
@@ -31,6 +31,8 @@ class ObjGraphicsMgr
               m_pOGr = pOGr ; }
       IObjGraphics* GetObjGraphics( void)
             { return m_pOGr ; }
+      const IObjGraphics* GetObjGraphics( void) const
+            { return m_pOGr ; }
       void Invalidate( void)
             { if ( m_pOGr != nullptr)
                  m_pOGr->Invalidate() ; }