diff --git a/EgtGraphics.rc b/EgtGraphics.rc
index 9a4d8fa..65d1c57 100644
Binary files a/EgtGraphics.rc and b/EgtGraphics.rc differ
diff --git a/SceneGrid.cpp b/SceneGrid.cpp
index d0990e0..8ac1a0c 100644
--- a/SceneGrid.cpp
+++ b/SceneGrid.cpp
@@ -15,6 +15,7 @@
 #include "stdafx.h"
 #include "Scene.h"
 #include "EGrUtils.h"
+#include "/EgtDev/Include/EgtNumUtils.h"
 #include <algorithm>
                     
 using namespace std ;
@@ -35,8 +36,8 @@ Scene::SetGridGeo( double dSnapStep, int nMinLineSstep, int nMajLineSstep, int n
    const double MIN_SNAP_STEP = 0.1 ;
    m_dSnapStep = max( abs( dSnapStep), MIN_SNAP_STEP) ;
    m_nMinLineSstep = abs( nMinLineSstep) ;
-   m_nMajLineSstep = abs( nMajLineSstep) ;
-   m_nExtSstep = abs( nExtSstep) ;
+   m_nMajLineSstep = max( abs( nMajLineSstep), m_nMinLineSstep) ;
+   m_nExtSstep = max( abs( nExtSstep), m_nMajLineSstep) ;
    return true ;
 }
 
@@ -49,6 +50,26 @@ Scene::SetGridColor( Color colMinLine, Color colMajLine)
    return true ;
 }
 
+//----------------------------------------------------------------------------
+static int
+GetSpecialCoeff( double dVal)
+{
+   if ( dVal < 1.99)
+      return 1 ;
+   else if ( dVal < 4.99)
+      return 2 ;
+   else if ( dVal < 9.99)
+      return 5 ;
+   else if ( dVal < 24.99)
+      return 10 ;
+   else if ( dVal < 49.99)
+      return 25 ;
+   else if ( dVal < 99.99)
+      return 50 ;
+   else
+      return 100 ;
+}
+
 //----------------------------------------------------------------------------
 bool
 Scene::DrawGrid( void)
@@ -73,35 +94,40 @@ Scene::DrawGrid( void)
 
   // se richiesto, disegno la griglia
    if ( m_bShowGrid) {
-     // disegno linee minori (a trattini)
-      glLineStipple( 2, 0xAAAA) ;
-      glEnable( GL_LINE_STIPPLE) ;
-      glBegin( GL_LINES) ;
-      glColor3f( m_colMinLine.GetRed(), m_colMinLine.GetGreen(), m_colMinLine.GetBlue()) ;
-      for ( int i = m_nMinLineSstep ; i <= m_nExtSstep ; i += m_nMinLineSstep) {
-        // se non si sovrappongono alle maggiori
-         if ( ( i % m_nMajLineSstep) != 0) {
-            float dPos = float( i * m_dSnapStep) ;
-            // X +
-            glVertex3f( dPos, - dExt, Z_DOWN) ;
-            glVertex3f( dPos, dExt, Z_DOWN) ;
-            // X -
-            glVertex3f( - dPos, - dExt, Z_DOWN) ;
-            glVertex3f( - dPos, dExt, Z_DOWN) ;
-            // Y +
-            glVertex3f( - dExt, dPos, Z_DOWN) ;
-            glVertex3f( dExt, dPos, Z_DOWN) ;
-            // Y -
-            glVertex3f( - dExt, - dPos, Z_DOWN) ;
-            glVertex3f( dExt, - dPos, Z_DOWN) ;
+     // disegno linee minori (a trattini), se non troppe
+      double dMinRapp = min( m_dHalfWidth, m_dHalfHeight) / ( m_dSnapStep * m_nMinLineSstep) ;
+      if ( dMinRapp < 60) {
+         glLineStipple( 2, 0xAAAA) ;
+         glEnable( GL_LINE_STIPPLE) ;
+         glBegin( GL_LINES) ;
+         glColor3f( m_colMinLine.GetRed(), m_colMinLine.GetGreen(), m_colMinLine.GetBlue()) ;
+         for ( int i = m_nMinLineSstep ; i <= m_nExtSstep ; i += m_nMinLineSstep) {
+           // se non si sovrappongono alle maggiori
+            if ( ( i % m_nMajLineSstep) != 0) {
+               float dPos = float( i * m_dSnapStep) ;
+               // X +
+               glVertex3f( dPos, - dExt, Z_DOWN) ;
+               glVertex3f( dPos, dExt, Z_DOWN) ;
+               // X -
+               glVertex3f( - dPos, - dExt, Z_DOWN) ;
+               glVertex3f( - dPos, dExt, Z_DOWN) ;
+               // Y +
+               glVertex3f( - dExt, dPos, Z_DOWN) ;
+               glVertex3f( dExt, dPos, Z_DOWN) ;
+               // Y -
+               glVertex3f( - dExt, - dPos, Z_DOWN) ;
+               glVertex3f( dExt, - dPos, Z_DOWN) ;
+            }
          }
+         glEnd() ;
+         glDisable( GL_LINE_STIPPLE) ;
       }
-      glEnd() ;
-      glDisable( GL_LINE_STIPPLE) ;
      // disegno linee maggiori
+      double dMaxRapp = min( m_dHalfWidth, m_dHalfHeight) / ( m_dSnapStep * m_nMajLineSstep) ;
+      int nCoeff = GetSpecialCoeff( 0.06 * dMaxRapp) ;
       glBegin( GL_LINES) ;
       glColor3f( m_colMajLine.GetRed(), m_colMajLine.GetGreen(), m_colMajLine.GetBlue()) ;
-      for ( int i = m_nMajLineSstep ; i <= m_nExtSstep ; i += m_nMajLineSstep) {
+      for ( int i = min( nCoeff * m_nMajLineSstep, m_nExtSstep) ; i <= m_nExtSstep ; i += nCoeff * m_nMajLineSstep) {
          float dPos = float( i * m_dSnapStep) ;
          // X +
          glVertex3f( dPos, - dExt, Z_DOWN) ;