diff --git a/VolZmapVolume.cpp b/VolZmapVolume.cpp
index c45303a..66f2145 100644
--- a/VolZmapVolume.cpp
+++ b/VolZmapVolume.cpp
@@ -3785,65 +3785,38 @@ VolZmap::CompPar_ZMilling( unsigned int nGrid, double dLenX, double dLenY, doubl
                            const Point3d& ptS, const Point3d& ptE,
                            const Vector3d& vtToolDir, const Vector3d& vtAux)
 {  
-  // uso funzione generica per verifica rapida
-   return CompPar_Milling( nGrid, dLenX, dLenY, dLenZ, ptS, ptE, vtToolDir, vtAux) ;
-
   // Controllo sull'interferenza utensile-solido
    unsigned int nStartI, nStartJ, nEndI, nEndJ ;
    bool bInterf = BBoxParaComp( nGrid, dLenX, dLenY, dLenZ, ptS, ptE, vtToolDir, vtAux, nStartI, nStartJ, nEndI, nEndJ) ;
    if ( ! bInterf)
       return true ;
 
-  // Materiale asportato nelle posizioni iniziale e finale
-
-  // Costruisco un sistema di riferimento nel piano
-   Point3d ptSXY( ptS.x, ptS.y, 0) ;
-   Point3d ptEXY( ptE.x, ptE.y, 0) ;
-   Vector3d vtV1 = vtToolDir ^ vtAux ;
-   Vector3d vtV2 = vtAux ;
-
-   if ( vtV1 * ( ptE - ptS) < 0)
-      vtV1 *= - 1 ;
-
-   double dLenMove = ( ( ( ptE - ptS) * vtV1) * vtV1).Len() ;
-
-  // Quote estreme del volume asportato
+  // Quote estreme Z 
    double dMinZ = min( min( ptS.z, ptS.z - vtToolDir.z * dLenZ), min( ptE.z, ptE.z - vtToolDir.z * dLenZ)) ;
    double dMaxZ = max( max( ptS.z, ptS.z - vtToolDir.z * dLenZ), max( ptE.z, ptE.z - vtToolDir.z * dLenZ)) ;
 
+  // Vettore di movimento
+   Vector3d vtMove = ptE - ptS ;
+
+  // Sistemi di riferimento del solido nella posizione iniziale e finale
+   Vector3d vtV2 = vtAux ; 
+   Vector3d vtV1 = vtV2 ^ vtToolDir ;
+   vtV1.Normalize() ;
+   Point3d ptSXY( ptS.x, ptS.y, 0) ;
+   Point3d ptEXY( ptE.x, ptE.y, 0) ;
+  
   // Studio del volume asportato durante il moto
-
-  // Studio delle simmetrie
-   
-   Point3d ptLs = ( ( ptE - ptS) * vtAux > 0 ? ptS : ptE) ;
-   Point3d ptLe = ( ( ptE - ptS) * vtAux > 0 ? ptE : ptS) ;
-
-   Vector3d vtMove = ptLe - ptLs ;
-
-   Vector3d vtW3 = vtAux ;
-   Vector3d vtAnsatz = ( vtW3 ^ vtToolDir) ;
-
-   bool bSymmetry =  vtMove * ( vtW3 ^ vtToolDir) > 0 ;
-
-   Vector3d vtW2 = ( bSymmetry ? vtAnsatz : - vtAnsatz) ;
-   Vector3d vtW1 = ( bSymmetry ? vtToolDir : - vtToolDir) ;
-
-
-   Point3d ptDiagMin = ptLs - vtW2 * ( 0.5 * dLenX) + vtW3 * ( 0.5 * dLenY) ;
-   Point3d ptDiagMax = ptLs + vtW2 * ( 0.5 * dLenX) - vtW3 * ( 0.5 * dLenY) ;
-
-   Vector3d vtU1 = ptDiagMax - ptDiagMin ; vtU1.Normalize() ;
-   Vector3d vtU2 = ( vtU1 * vtMove > 0 ? vtMove - vtMove * vtU1  * vtU1 :
-                                         vtMove * vtU1 * vtU1 - vtMove) ;
-   vtU2.Normalize() ;
-
-   Point3d ptOMot = ( vtMove * vtU1 > 0 ? ptDiagMin : ptDiagMin + vtMove) ;
-
-   Point3d ptOMotXY( ptOMot.x, ptOMot.y, 0) ;
-
-   double dLen1 = vtMove * vtU1 ;
-   double dLen2 = vtMove * vtU2 ;
-   double dHx = ( ptDiagMax - ptDiagMin).Len() ;
+   Frame3d MotionFrame ;
+   Vector3d vtDiagA = dLenX * vtV1 + dLenY * vtV2 ;
+   Vector3d vtDiagB = dLenX * vtV1 - dLenY * vtV2 ;
+   Vector3d vtW1 = ( abs( vtDiagA * vtMove) <= abs( vtDiagB * vtMove) ? vtDiagA : vtDiagB) ;
+   Point3d ptOrigXY = ptSXY - vtW1 / 2 ;
+   double dLenW1 = vtW1.Len() ;
+   vtW1 /= dLenW1 ;
+   double dDeltaW1 = vtMove * vtW1 ;
+   Vector3d vtW2 = vtMove - dDeltaW1 * vtW1 ;
+   double dLenW2 = vtW2.Len() ;
+   vtW2 /= dLenW2 ;
 
    for ( unsigned int i = nStartI ; i <= nEndI ; ++ i) {
       for ( unsigned int j = nStartJ ; j <= nEndJ ; ++ j) {
@@ -3872,12 +3845,12 @@ VolZmap::CompPar_ZMilling( unsigned int nGrid, double dLenX, double dLenY, doubl
             SubtractIntervals( nGrid, i, j, dMinZ, dMaxZ, Z_AX, - Z_AX) ;
 
         // Asportazione materiale nel moto
-         Vector3d vtR = ptC - ptOMotXY ;
-         double dR1 = vtR * vtU1 ;
-         double dR2 = vtR * vtU2 ;
-         if ( dR2 > EPS_SMALL  &&  dR2 < dLen2 - EPS_SMALL  && 
-              dR1 * dLen2 > dLen1 * dR2 + EPS_SMALL  && 
-              dR1 * dLen2 < dHx * dLen2 + dLen1 * dR2 - EPS_SMALL)
+         Vector3d vtR = ptC - ptOrigXY ;
+         double dR1 = vtR * vtW1 ;
+         double dR2 = vtR * vtW2 ;
+         if ( dR2 > EPS_SMALL  &&  dR2 < dLenW2 - EPS_SMALL  && 
+              dR1 * dLenW2 > /*dLenW1*/dDeltaW1 * dR2 + EPS_SMALL  && 
+              dR1 * dLenW2 < /*dDeltaW1*/dLenW1 * dLenW2 + /*dLenW1*/ dDeltaW1 * dR2 - EPS_SMALL)
             SubtractIntervals( nGrid, i, j, dMinZ, dMaxZ, Z_AX, - Z_AX) ;
       }
    }