diff --git a/TestEGr.rc b/TestEGr.rc
index 4fa46c8..c2a7308 100644
Binary files a/TestEGr.rc and b/TestEGr.rc differ
diff --git a/TestEGrDlg.cpp b/TestEGrDlg.cpp
index 6621699..9728e57 100644
--- a/TestEGrDlg.cpp
+++ b/TestEGrDlg.cpp
@@ -144,6 +144,7 @@ BEGIN_MESSAGE_MAP( CTestEGrDlg, CDialog)
    ON_BN_CLICKED( IDC_IMPORT, OnFileImport)
    ON_BN_CLICKED( IDC_EXEC, OnFileExec)
    ON_CONTROL_RANGE( BN_CLICKED, IDC_WIREFRAME, IDC_SHADING, OnShowMode)
+   ON_BN_CLICKED( IDC_SHOWCURVEDIR, OnShowCurveDir)
    ON_CONTROL_RANGE( BN_CLICKED, IDC_ZOOM_ALL, IDC_ZOOM_OUT, OnZoom)
    ON_CONTROL_RANGE( BN_CLICKED, IDC_VIEW_TOP, IDC_VIEW_ISO, OnView)
    ON_BN_CLICKED( IDC_CLOSE, OnClose)
@@ -232,6 +233,13 @@ CTestEGrDlg::OnInitDialog( void)
       UpdateShowModeButtons() ;
    }
 
+  // recupero lo stato di visualizzazione direzione curve
+   if ( m_View.GetScene() != nullptr) {
+      bool bCrvDir = ( GetPrivateProfileInt( "Scene", "CurveDir", 0, AfxGetApp()->m_pszProfileName) != 0) ;
+      m_View.GetScene()->SetShowCurveDirection( bCrvDir) ;
+      UpdateShowCurveDir() ;
+   }
+
   // recupero gli angoli di vista e li imposto
    if ( m_View.GetScene() != nullptr) {
       double dAngVdeg = 0, dAngOdeg = 0 ;
@@ -475,6 +483,7 @@ CTestEGrDlg::OnSize( UINT nType, int cx, int cy)
       MoveDlgItem( IDC_WIREFRAME, IP_TR, cx, cy) ;
       MoveDlgItem( IDC_HIDDENLINE, IP_TR, cx, cy) ;
       MoveDlgItem( IDC_SHADING, IP_TR, cx, cy) ;
+      MoveDlgItem( IDC_SHOWCURVEDIR, IP_TR, cx, cy) ;
       MoveDlgItem( IDC_ZOOM_ALL, IP_TR, cx, cy) ;
       MoveDlgItem( IDC_ZOOM_IN, IP_TR, cx, cy) ;
       MoveDlgItem( IDC_ZOOM_OUT, IP_TR, cx, cy) ;
@@ -625,6 +634,10 @@ CTestEGrDlg::OnClose( void)
    int nShMode = m_View.GetScene()->GetShowMode() ;
    WritePrivateProfileInt( "Scene", "ShowMode", nShMode, AfxGetApp()->m_pszProfileName) ;
 
+  // salvo stato visualizzazione direzione curve
+   bool bCrvDir = m_View.GetScene()->GetShowCurveDirection() ;
+   WritePrivateProfileInt( "Scene", "CurveDir", bCrvDir, AfxGetApp()->m_pszProfileName) ;
+
   // salvo gli angoli di vista
    double dAngVdeg, dAngOdeg ;
    m_View.GetScene()->GetCamera( &dAngVdeg, &dAngOdeg) ;
@@ -850,6 +863,22 @@ CTestEGrDlg::UpdateShowModeButtons( void)
    (( CButton*) GetDlgItem( IDC_SHADING))->SetCheck( ( nSM == SM_SHADING ? BST_CHECKED : BST_UNCHECKED)) ;
 }
 
+//----------------------------------------------------------------------------
+void
+CTestEGrDlg::OnShowCurveDir( void)
+{
+   bool bShow = ( (( CButton*) GetDlgItem( IDC_SHOWCURVEDIR))->GetCheck() == BST_CHECKED) ;
+   m_View.ShowCurveDir( bShow) ;
+}
+
+//----------------------------------------------------------------------------
+void
+CTestEGrDlg::UpdateShowCurveDir( void)
+{
+   bool bShow = m_View.GetScene()->GetShowCurveDirection() ;
+   (( CButton*) GetDlgItem( IDC_SHOWCURVEDIR))->SetCheck( ( bShow ? BST_CHECKED : BST_UNCHECKED)) ;
+}
+
 //----------------------------------------------------------------------------
 void
 CTestEGrDlg::OnZoom( UINT nID)
diff --git a/TestEGrDlg.h b/TestEGrDlg.h
index 1a2c52a..eb7e58e 100644
--- a/TestEGrDlg.h
+++ b/TestEGrDlg.h
@@ -37,6 +37,7 @@ class CTestEGrDlg : public CDialog
               { return m_View.GetSceneInfo( sInfo) ; }
       bool LineExec( const std::string& sLine) ;
       void UpdateShowModeButtons( void) ;
+      void UpdateShowCurveDir( void) ;
       void UpdateViewButtons( void) ;
 
    protected :
@@ -52,6 +53,7 @@ class CTestEGrDlg : public CDialog
       afx_msg void OnFileImport( void) ;
       afx_msg void OnFileExec( void) ;
       afx_msg void OnShowMode( UINT nID) ;
+      afx_msg void OnShowCurveDir( void) ;
       afx_msg void OnZoom( UINT nID) ;
       afx_msg void OnView( UINT nID) ;
       afx_msg void OnCommand( void) ;
diff --git a/TestEGrUtils.cpp b/TestEGrUtils.cpp
index 9d9bd60..c354d26 100644
--- a/TestEGrUtils.cpp
+++ b/TestEGrUtils.cpp
@@ -50,5 +50,6 @@ void
 UpdateButtons( void)
 {
    ((CTestEGrDlg*)AfxGetMainWnd())->UpdateShowModeButtons() ;
+   ((CTestEGrDlg*)AfxGetMainWnd())->UpdateShowCurveDir() ;
    ((CTestEGrDlg*)AfxGetMainWnd())->UpdateViewButtons() ;
 }
diff --git a/TestEGrView.cpp b/TestEGrView.cpp
index 0578347..a469829 100644
--- a/TestEGrView.cpp
+++ b/TestEGrView.cpp
@@ -181,6 +181,9 @@ TestEGrView::Redraw( void)
 void
 TestEGrView::ShowMode( UINT nID)
 {
+   if ( m_pScene == nullptr)
+      return ;
+
    switch ( nID) {
    case IDC_WIREFRAME :
       m_pScene->SetShowMode( SM_WIREFRAME) ;
@@ -199,6 +202,17 @@ TestEGrView::ShowMode( UINT nID)
    RedrawWindow() ;
 }
 
+//----------------------------------------------------------------------------
+void
+TestEGrView::ShowCurveDir( bool bShow)
+{
+   if ( m_pScene == nullptr)
+      return ;
+   m_pScene->SetShowCurveDirection( bShow) ;
+
+   RedrawWindow() ;
+}
+
 //----------------------------------------------------------------------------
 void
 TestEGrView::Zoom( UINT nID)
diff --git a/TestEGrView.h b/TestEGrView.h
index 9058a81..6ae3c45 100644
--- a/TestEGrView.h
+++ b/TestEGrView.h
@@ -25,6 +25,7 @@ class TestEGrView : public CWnd
       bool Reshape( int nX, int nY, int nW, int nH) ;
       void Redraw( void) ;
       void ShowMode( UINT nID) ;
+      void ShowCurveDir( bool bShow) ;
       void Zoom( UINT nID) ;
       void View( UINT nID) ;
 
diff --git a/resource.h b/resource.h
index 99a40cd..cc020d4 100644
Binary files a/resource.h and b/resource.h differ