diff --git a/EgtGraphics.rc b/EgtGraphics.rc
index db43769..9463bb6 100644
Binary files a/EgtGraphics.rc and b/EgtGraphics.rc differ
diff --git a/SceneGeom.cpp b/SceneGeom.cpp
index 39b09f3..1e56415 100644
--- a/SceneGeom.cpp
+++ b/SceneGeom.cpp
@@ -178,10 +178,10 @@ Scene::DrawGeoObj( const IGdbIterator& iIter, int nPass, const MdStMkCol& siObj)
       if ( nGeoType == VOL_ZMAP) {
          const IVolZmap* pZmap = GetVolZmap( pGeoObj) ;
          if ( pZmap != nullptr) {
-            switch ( m_nShowZmap) {
-            case ZSM_SURF : nCount = pZmap->GetBlockCount() ; break ;
-            case ZSM_BOTH : nCount = pZmap->GetBlockCount() + 1 ; break ;
-            }
+            if ( ( m_nShowZmap & ZSM_SURF) != 0)
+               nCount += pZmap->GetBlockCount() ;
+            if ( ( m_nShowZmap & ZSM_LINES) != 0  ||  ( m_nShowZmap & ZSM_NORMALS) != 0)
+               nCount += 1 ;
          }
       }
      // nuova modalità grafica solo per superfici con molti triangoli o solidi Zmap
@@ -381,15 +381,17 @@ Scene::DrawGeoObj( const IGdbIterator& iIter, int nPass, const MdStMkCol& siObj)
                pGraphics->EndTriangles() ;
             }
          }
-        // visualizzazione spilloni (sempre nell'ultimo blocco)
-         if ( m_nShowZmap == ZSM_LINES  ||  m_nShowZmap == ZSM_BOTH) {
+        // visualizzazione spilloni e normali (sempre nell'ultimo blocco)
+         if ( ( m_nShowZmap & ZSM_LINES) != 0  ||  ( m_nShowZmap & ZSM_NORMALS) != 0) {
            // imposto indice blocco corrente
             pGraphics->SetCurrent( nCount) ;
            // lo pulisco
             pGraphics->Clear() ;
            // ciclo sui tre gruppi di spilloni
-            Color vCol[3] = {BLUE, RED, GREEN} ;
-            for ( int k = 0 ; k < 3 ; ++ k) {
+            int nKmin = ( m_nShowZmap & ZSM_LINES) != 0 ? 0 : 3 ;
+            int nKmax = ( m_nShowZmap & ZSM_NORMALS) != 0 ? 6 : 3 ;
+            Color vCol[6] = {BLUE, RED, GREEN, BLUE, RED, GREEN} ;
+            for ( int k = nKmin ; k < nKmax ; ++ k) {
                pGraphics->AddColor( vCol[k]) ;
                pGraphics->AddMaterial( vCol[k], vCol[k], vCol[k], 10) ;
                pGraphics->AddBackMaterial( vCol[k]) ;