diff --git a/IntersPlaneVolZmap.cpp b/IntersPlaneVolZmap.cpp
index 9f6e0a2..ad99de2 100644
--- a/IntersPlaneVolZmap.cpp
+++ b/IntersPlaneVolZmap.cpp
@@ -19,7 +19,7 @@
 using namespace std ;
 
 //----------------------------------------------------------------------------
-//  Intersezione di unpiano con la superficie di un solido VolZmap
+//  Intersezione di un piano con la superficie di un solido VolZmap
 //----------------------------------------------------------------------------
 bool
 IntersPlaneVolZmap( const Plane3d& plPlane, const IVolZmap& Vzm, ICURVEPOVECTOR& vpLoop)
@@ -28,9 +28,6 @@ IntersPlaneVolZmap( const Plane3d& plPlane, const IVolZmap& Vzm, ICURVEPOVECTOR&
    const VolZmap* pVzm = GetBasicVolZmap( &Vzm) ;
    if ( pVzm == nullptr)
       return false ;
-  // verifico parametro di ritorno
-   if ( &vpLoop == nullptr)
-      return false ;
 
   // eseguo intersezione
    return pVzm->GetPlaneIntersection( plPlane, vpLoop) ;
diff --git a/VolZmap.cpp b/VolZmap.cpp
index fdc44d8..c435347 100644
--- a/VolZmap.cpp
+++ b/VolZmap.cpp
@@ -507,11 +507,15 @@ VolZmap::GetLocalBBox( BBox3d& b3Loc, int nFlag) const
          }
         // passo al punto successivo
          dX += m_dStep ;
+         if ( m_nMapNum == N_MAPS)
+            dX = min( dX, m_dMaxZ[1]) ;
       }
      // passo alla riga successiva
       dY += m_dStep ;
+      if ( m_nMapNum == N_MAPS)
+         dY = min( dY, m_dMaxZ[2]) ;
    }
-//
+
    return true ;
 }
 
@@ -551,9 +555,13 @@ VolZmap::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
          }
         // passo al punto successivo
          dX += m_dStep ;
+         if ( m_nMapNum == N_MAPS)
+            dX = min( dX, m_dMaxZ[1]) ;
       }
      // passo alla riga successiva
       dY += m_dStep ;
+      if ( m_nMapNum == N_MAPS)
+         dY = min( dY, m_dMaxZ[2]) ;
    }
 
    return true ;
diff --git a/VolZmapCalculus.cpp b/VolZmapCalculus.cpp
index 408593a..178f2ae 100644
--- a/VolZmapCalculus.cpp
+++ b/VolZmapCalculus.cpp
@@ -3080,17 +3080,18 @@ VolZmap::GetPlaneIntersection( const Plane3d& plPlane, ICURVEPOVECTOR& vpLoop) c
          return false ;
      // Se c'è intersezione valuto tutti i voxel interni
       if ( TestIntersPlaneBox( plPlaneLoc, b3BlockBox)) {    
-        // Ciclo sui voxel del blocco.    
         // Triangoli smooth
-         for ( int nV = 0 ; nV < int( m_BlockSmoothTria[nB].size()) ; ++ nV) {
+        // ciclo sui voxel del blocco.    
+         for ( int nV = 0 ; nV < ssize( m_BlockSmoothTria[nB]) ; ++ nV) {
            // Box del voxel
             BBox3d b3Vox ;
             GetVoxelBox( m_BlockSmoothTria[nB][nV].i, m_BlockSmoothTria[nB][nV].j, m_BlockSmoothTria[nB][nV].k, b3Vox) ;
-            // Se non c'è intersezione col voxel, passo al successivo.
+           // Se non c'è intersezione col voxel, passo al successivo.
             if ( ! TestIntersPlaneBox( plPlaneLoc, b3Vox))
                continue ; 
-            for ( int nT = 0 ; nT < int( m_BlockSmoothTria[nB][nV].vTria.size()) ; ++ nT) {
-               Triangle3d trTria = m_BlockSmoothTria[nB][nV].vTria[nT] ;
+           // ciclo sui triangoli del voxel
+            for ( int nT = 0 ; nT < ssize( m_BlockSmoothTria[nB][nV].vTria) ; ++ nT) {
+               const Triangle3d& trTria = m_BlockSmoothTria[nB][nV].vTria[nT] ;
                Point3d ptSt, ptEn ;
                int nIntersType = IntersPlaneTria( plPlane, trTria, ptSt, ptEn) ;
                if ( nIntersType == IPTT_EDGE  ||  nIntersType == IPTT_YES) {
@@ -3102,18 +3103,18 @@ VolZmap::GetPlaneIntersection( const Plane3d& plPlane, ICURVEPOVECTOR& vpLoop) c
             }
          }
         // Triangoli sharp interni al blocco    
-         for ( int nV = 0 ; nV < int( m_BlockSharpTria[nB].size()) ; ++ nV) {
+        // ciclo sui voxel del blocco.    
+         for ( int nV = 0 ; nV < ssize( m_BlockSharpTria[nB]) ; ++ nV) {
            // Box del voxel     
             BBox3d b3Vox ;
             GetVoxelBox( m_BlockSharpTria[nB][nV].i, m_BlockSharpTria[nB][nV].j, m_BlockSharpTria[nB][nV].k, b3Vox) ;
-           // Se non c'è intersezione col voxel, passo al successivo.
            // Ciclo sulle componenti connesse
-            for ( int nC = 0 ; nC < int( m_BlockSharpTria[nB][nV].vCompoTria.size()) ; ++ nC) {
-               for ( int nT = 0 ; nT < int( m_BlockSharpTria[nB][nV].vCompoTria[nC].size()) ; ++ nT) {
-                  Triangle3d trTria = m_BlockSharpTria[nB][nV].vCompoTria[nC][nT] ;
+            for ( int nC = 0 ; nC < ssize( m_BlockSharpTria[nB][nV].vCompoTria) ; ++ nC) {
+               for ( int nT = 0 ; nT < ssize( m_BlockSharpTria[nB][nV].vCompoTria[nC]) ; ++ nT) {
+                  const Triangle3d& trTria = m_BlockSharpTria[nB][nV].vCompoTria[nC][nT] ;
                   Point3d ptSt, ptEn ;
-                  int nIntersType = IntersPlaneTria(plPlane, trTria, ptSt, ptEn) ;
-                  if (nIntersType == IPTT_EDGE || nIntersType == IPTT_YES) {
+                  int nIntersType = IntersPlaneTria( plPlane, trTria, ptSt, ptEn) ;
+                  if ( nIntersType == IPTT_EDGE  ||  nIntersType == IPTT_YES) {
                     // Costruisco il tratto di curva
                      CurveLine cvLine ;
                      if ( cvLine.Set(ptSt, ptEn))
@@ -3123,10 +3124,10 @@ VolZmap::GetPlaneIntersection( const Plane3d& plPlane, ICURVEPOVECTOR& vpLoop) c
             }
          }
         // Triangoli grandi del blocco
-         for ( int nT = 0 ; nT < int( m_BlockBigTria[nB].size()) ; ++ nT) {
-            Triangle3d trTria = m_BlockBigTria[nB][nT] ;
+         for ( int nT = 0 ; nT < ssize( m_BlockBigTria[nB]) ; ++ nT) {
+            const Triangle3d& trTria = m_BlockBigTria[nB][nT] ;
             Point3d ptSt, ptEn ;
-            int nIntersType = IntersPlaneTria(plPlane, trTria, ptSt, ptEn) ;
+            int nIntersType = IntersPlaneTria( plPlane, trTria, ptSt, ptEn) ;
             if ( nIntersType == IPTT_EDGE  ||  nIntersType == IPTT_YES) {
                // Costruisco il tratto di curva
                CurveLine cvLine ;
@@ -3136,11 +3137,11 @@ VolZmap::GetPlaneIntersection( const Plane3d& plPlane, ICURVEPOVECTOR& vpLoop) c
          }
       }
      // In ogni caso valuto i triangoli sharp fra blocchi
-      for ( int nV = 0 ; nV < int( m_InterBlockSharpTria[nB].size()) ; ++ nV) {
+      for ( int nV = 0 ; nV < ssize( m_InterBlockSharpTria[nB]) ; ++ nV) {
         // Ciclo sulle componenti connesse
-         for ( int nC = 0 ; nC < int( m_InterBlockSharpTria[nB][nV].vCompoTria.size()) ; ++ nC) {
-            for ( int nT = 0 ; nT < int( m_InterBlockSharpTria[nB][nV].vCompoTria[nC].size()) ; ++ nT) {
-               Triangle3d trTria = m_InterBlockSharpTria[nB][nV].vCompoTria[nC][nT] ;
+         for ( int nC = 0 ; nC < ssize( m_InterBlockSharpTria[nB][nV].vCompoTria) ; ++ nC) {
+            for ( int nT = 0 ; nT < ssize( m_InterBlockSharpTria[nB][nV].vCompoTria[nC]) ; ++ nT) {
+               const Triangle3d& trTria = m_InterBlockSharpTria[nB][nV].vCompoTria[nC][nT] ;
                Point3d ptSt, ptEn ;
                int nIntersType = IntersPlaneTria( plPlane, trTria, ptSt, ptEn) ;
                if ( nIntersType == IPTT_EDGE  ||  nIntersType == IPTT_YES) {
@@ -3156,9 +3157,9 @@ VolZmap::GetPlaneIntersection( const Plane3d& plPlane, ICURVEPOVECTOR& vpLoop) c
    
   // Creo i loop
    ChainCurves LoopCreator ;
-   LoopCreator.Init( false, EPS_SMALL, int( vLine.size())) ;
+   LoopCreator.Init( false, EPS_SMALL, ssize( vLine)) ;
   // Carico le curve per concatenarle
-   for ( int nCv = 0 ; nCv < int( vLine.size()) ; ++ nCv) {
+   for ( int nCv = 0 ; nCv < ssize( vLine) ; ++ nCv) {
       Point3d ptSt = vLine[nCv].GetStart() ;
       Point3d ptEn = vLine[nCv].GetEnd() ;
       Vector3d vtDir; vLine[nCv].GetStartDir(vtDir) ;