diff --git a/LuaLibs/FaceData.lua b/LuaLibs/FaceData.lua
index fa426fa..bae8104 100644
--- a/LuaLibs/FaceData.lua
+++ b/LuaLibs/FaceData.lua
@@ -114,7 +114,7 @@ local function GetEdgesInfo( Proc, idFace )
 
       local CurrentEdge = {}
       CurrentEdge.idAdjacentFace = EdgesEgt[i].Adj
-      CurrentEdge.vtToolDirection = Vector3d( EdgesEgt[i].Norm)
+      CurrentEdge.vtN = Vector3d( EdgesEgt[i].Norm)
       CurrentEdge.dLength = EdgesEgt[i].Len
       CurrentEdge.dElevation = abs( EdgesEgt[i].Elev)
       CurrentEdge.bIsOpen = EdgesEgt[i].Open
@@ -298,7 +298,7 @@ local function GetBottomFaces( Proc)
 
       local CurrentEdge = {}
       CurrentEdge.idAdjacentFace = BottomFaces[1].Edges[i].idAdjacentFace
-      CurrentEdge.vtToolDirection = BottomFaces[1].Edges[i].vtToolDirection
+      CurrentEdge.vtN = BottomFaces[1].Edges[i].vtN
       CurrentEdge.dLength = BottomFaces[1].Edges[i].dLength
       CurrentEdge.bIsOpen = BottomFaces[1].Edges[i].bIsOpen
       CurrentEdge.dElevation = BottomFaces[1].Edges[i].dElevation
@@ -386,7 +386,7 @@ local function GetLongFaces( Proc, MainFaces)
 
          local CurrentEdge = {}
          CurrentEdge.idAdjacentFace = LongFaces[i].Edges[j].idAdjacentFace
-         CurrentEdge.vtToolDirection = LongFaces[i].Edges[j].vtToolDirection
+         CurrentEdge.vtN = LongFaces[i].Edges[j].vtN
          CurrentEdge.dLength = LongFaces[i].Edges[j].dLength
          CurrentEdge.bIsOpen = LongFaces[i].Edges[j].bIsOpen
          CurrentEdge.dElevation = LongFaces[i].Edges[j].dElevation
@@ -475,7 +475,7 @@ local function GetSideFaces( Proc, MainFaces)
 
          local CurrentEdge = {}
          CurrentEdge.idAdjacentFace = SideFaces[i].Edges[j].idAdjacentFace
-         CurrentEdge.vtToolDirection = SideFaces[i].Edges[j].vtToolDirection
+         CurrentEdge.vtN = SideFaces[i].Edges[j].vtN
          CurrentEdge.dLength = SideFaces[i].Edges[j].dLength
          CurrentEdge.bIsOpen = SideFaces[i].Edges[j].bIsOpen
          CurrentEdge.dElevation = SideFaces[i].Edges[j].dElevation
diff --git a/LuaLibs/MachiningLib.lua b/LuaLibs/MachiningLib.lua
index 3c1692a..9f2f937 100644
--- a/LuaLibs/MachiningLib.lua
+++ b/LuaLibs/MachiningLib.lua
@@ -362,16 +362,16 @@ function MachiningLib.FindChainSaw( Proc, ToolSearchParameters)
 
    -- parametri obbligatori
    if type( ToolSearchParameters.vtToolDirection) ~= 'table' then
-      error( 'FindBlade : missing tool direction')
+      error( 'FindChainSaw : missing tool direction')
    end
    if type( ToolSearchParameters.bAllowTopHead) ~= 'boolean' then
-      error( 'FindBlade : missing top head info')
+      error( 'FindChainSaw : missing top head info')
    end
    if type( ToolSearchParameters.bAllowBottomHead) ~= 'boolean' then
-      error( 'FindBlade : missing bottom head info')
+      error( 'FindChainSaw : missing bottom head info')
    end
    if not ToolSearchParameters.bAllowTopHead and not ToolSearchParameters.bAllowBottomHead then
-      error( 'FindBlade : wrong head info')
+      error( 'FindChainSaw : wrong head info')
    end
 
    -- parametri opzionali
diff --git a/Strategies/Standard/HEADCUT/HEADCUT.lua b/Strategies/Standard/HEADCUT/HEADCUT.lua
index 7d9bd60..7f2a524 100644
--- a/Strategies/Standard/HEADCUT/HEADCUT.lua
+++ b/Strategies/Standard/HEADCUT/HEADCUT.lua
@@ -72,7 +72,7 @@ end
 local function GetEdgeToMachine( Proc, vtEdge)
    local Edge
    for i = 1, #Proc.Faces[1].Edges do
-      if AreSameVectorApprox( Proc.Faces[1].Edges[i].vtToolDirection, vtEdge) then
+      if AreSameVectorApprox( Proc.Faces[1].Edges[i].vtN, vtEdge) then
          Edge = Proc.Faces[1].Edges[i]
       end
    end
diff --git a/Strategies/Standard/STR0005/STR0005.lua b/Strategies/Standard/STR0005/STR0005.lua
index 26e98e4..6424be7 100644
--- a/Strategies/Standard/STR0005/STR0005.lua
+++ b/Strategies/Standard/STR0005/STR0005.lua
@@ -21,21 +21,21 @@ Blade.Result = {}
 -------------------------------------------------------------------------------------------------------------
 local function CompareEdges( EdgeA, EdgeB)
    -- prima i lati orientati lungo X
-   if abs( EdgeA.vtToolDirection:getX()) < abs( EdgeB.vtToolDirection:getX()) - 10 * GEO.EPS_SMALL then
+   if abs( EdgeA.vtN:getX()) < abs( EdgeB.vtN:getX()) - 10 * GEO.EPS_SMALL then
       return true
-   elseif abs( EdgeA.vtToolDirection:getX()) > abs( EdgeB.vtToolDirection:getX()) + 10 * GEO.EPS_SMALL then
+   elseif abs( EdgeA.vtN:getX()) > abs( EdgeB.vtN:getX()) + 10 * GEO.EPS_SMALL then
       return false
    -- se stessa X si preferiscono i lati più in basso
    else
-      if EdgeA.vtToolDirection:getZ() > EdgeB.vtToolDirection:getZ() + 10 * GEO.EPS_SMALL then
+      if EdgeA.vtN:getZ() > EdgeB.vtN:getZ() + 10 * GEO.EPS_SMALL then
          return true
-      elseif EdgeA.vtToolDirection:getZ() < EdgeB.vtToolDirection:getZ() - 10 * GEO.EPS_SMALL then
+      elseif EdgeA.vtN:getZ() < EdgeB.vtN:getZ() - 10 * GEO.EPS_SMALL then
          return false
       -- se stessa Z si preferiscono i lati verso il fronte della trave
       else
-         if EdgeA.vtToolDirection:getY() > EdgeB.vtToolDirection:getY() + 10 * GEO.EPS_SMALL then
+         if EdgeA.vtN:getY() > EdgeB.vtN:getY() + 10 * GEO.EPS_SMALL then
             return true
-         elseif EdgeA.vtToolDirection:getY() < EdgeB.vtToolDirection:getY() - 10 * GEO.EPS_SMALL then
+         elseif EdgeA.vtN:getY() < EdgeB.vtN:getY() - 10 * GEO.EPS_SMALL then
             return false
          else
             return false
@@ -119,7 +119,7 @@ function STR0005.Make( bAddMachining, Proc, Part, CustomParameters)
       -- ricerca utensile
       local ToolSearchParameters = {}
       ToolSearchParameters.dElevation = dDepthToMachine
-      ToolSearchParameters.vtToolDirection = EdgesSorted[1].vtToolDirection
+      ToolSearchParameters.vtToolDirection = EdgesSorted[1].vtN
       ToolSearchParameters.bAllowTopHead = true
       ToolSearchParameters.bAllowBottomHead = true
       ToolSearchParameters.bForceLongcutBlade = bForceLongcutBlade
diff --git a/StrategyLibs/FACEBYBLADE.lua b/StrategyLibs/FACEBYBLADE.lua
index 1d093e8..07dbdca 100644
--- a/StrategyLibs/FACEBYBLADE.lua
+++ b/StrategyLibs/FACEBYBLADE.lua
@@ -67,7 +67,7 @@ end
 function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalParameters)
    local Cutting = {}
 
-   local vtMachiningDirection = EdgeToMachine.vtToolDirection
+   local vtMachiningDirection = EdgeToMachine.vtN
    local vtN = Proc.Faces[FaceToMachine.id+1].vtN
    Cutting.sDepth = OptionalParameters.sDepth or 0
    Cutting.dLongitudinalOffset = OptionalParameters.dLongitudinalOffset or 0
diff --git a/StrategyLibs/SLOTBYBLADE.lua b/StrategyLibs/SLOTBYBLADE.lua
index 7a7b595..0b1beb2 100644
--- a/StrategyLibs/SLOTBYBLADE.lua
+++ b/StrategyLibs/SLOTBYBLADE.lua
@@ -109,21 +109,21 @@ function SLOTBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
    Cutting.dLengthToMachine = EdgeToMachine.dLength
    Cutting.dEdgeLength = EdgeToMachine.dLength
    -- TODO conviene spostare questi calcoli nel FaceData?
-   Cutting.ptEdge1, _, Cutting.ptEdge2 = EgtSurfTmFacetOppositeSide( Proc.id, FaceToMachine.id, -EdgeToMachine.vtToolDirection, GDB_ID.ROOT)
+   Cutting.ptEdge1, _, Cutting.ptEdge2 = EgtSurfTmFacetOppositeSide( Proc.id, FaceToMachine.id, -EdgeToMachine.vtN, GDB_ID.ROOT)
    local b3BoxEdge = BBox3d( Cutting.ptEdge1, Cutting.ptEdge2)
    Cutting.dLengthOnX = b3BoxEdge:getDimX()
    --
-   Cutting.vtToolDirection = EdgeToMachine.vtToolDirection
+   Cutting.vtToolDirection = EdgeToMachine.vtN
    if EdgeToMachine.bIsOpen then
-      Cutting.vtEdgeDirection = -EdgeToMachine.vtToolDirection ^ FaceToMachine.vtN
+      Cutting.vtEdgeDirection = -EdgeToMachine.vtN ^ FaceToMachine.vtN
    else
-      Cutting.vtEdgeDirection = EdgeToMachine.vtToolDirection ^ FaceToMachine.vtN
+      Cutting.vtEdgeDirection = EdgeToMachine.vtN ^ FaceToMachine.vtN
    end
 
    -- ricerca utensile
    local ToolSearchParameters = {}
    ToolSearchParameters.dElevation = abs( EdgeToMachine.dElevation)
-   ToolSearchParameters.vtToolDirection = EdgeToMachine.vtToolDirection
+   ToolSearchParameters.vtToolDirection = EdgeToMachine.vtN
    ToolSearchParameters.bAllowTopHead = true
    ToolSearchParameters.bAllowBottomHead = false
    ToolSearchParameters.bForceLongcutBlade = bForceLongcutBlade
@@ -215,12 +215,12 @@ function SLOTBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
    Cutting.dOverlap = 0
    -- faceuse
    if EdgeToMachine.dElevation > - 10 * GEO.EPS_SMALL then
-      Cutting.nFaceuse = BeamLib.GetNearestOrthoOpposite( EdgeToMachine.vtToolDirection)
+      Cutting.nFaceuse = BeamLib.GetNearestOrthoOpposite( EdgeToMachine.vtN)
    else
-      Cutting.nFaceuse = BeamLib.GetNearestOrthoOpposite( -EdgeToMachine.vtToolDirection)
+      Cutting.nFaceuse = BeamLib.GetNearestOrthoOpposite( -EdgeToMachine.vtN)
    end
    -- SCC
-   Cutting.nSCC = GetSCC( EdgeToMachine.vtToolDirection)
+   Cutting.nSCC = GetSCC( EdgeToMachine.vtN)
    -- asse bloccato
    Cutting.sBlockedAxis = BeamLib.GetBlockedAxis( Cutting.nToolIndex, 'perpendicular', Part.b3Raw, FaceToMachine.vtN, EgtIf( FaceToMachine.vtN:getX() > 0, X_AX(), -X_AX()))
    -- approccio e retrazione
@@ -248,7 +248,7 @@ function SLOTBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
 
    -- se lavorazione aperta sulla coda, eventuali aggiustamenti
    -- TODO valutare se fare funzione a parte
-   if Proc.AffectedFaces.bLeft and ( EdgeToMachine.sType == 'Bottom' or ( EdgeToMachine.vtToolDirection:getX() < 0.707)) then
+   if Proc.AffectedFaces.bLeft and ( EdgeToMachine.sType == 'Bottom' or ( EdgeToMachine.vtN:getX() < 0.707)) then
       local dLengthOnX = Cutting.dLengthOnX
       -- se feature splittata non si considera la lunghezza della feature per il check spostamento dopo separazione
       if bIsSplitFeature then
@@ -260,7 +260,7 @@ function SLOTBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
       if bStartLeft then
          dAddLengthLeftSide = Cutting.LeadIn.dStartAddLength
       end
-      if not AreSameOrOppositeVectorApprox( EdgeToMachine.vtToolDirection, Y_AX()) then
+      if not AreSameOrOppositeVectorApprox( EdgeToMachine.vtN, Y_AX()) then
          if MachiningLib.CanMoveAfterSplitcut( dLengthOnX, Part) then
             Cutting.sStage = 'AfterTail'
          else
diff --git a/StrategyLibs/SLOTBYCHAINSAW.lua b/StrategyLibs/SLOTBYCHAINSAW.lua
index 5ce1e26..dbf2bff 100644
--- a/StrategyLibs/SLOTBYCHAINSAW.lua
+++ b/StrategyLibs/SLOTBYCHAINSAW.lua
@@ -74,14 +74,14 @@ function SLOTBYCHAINSAW.Make( Proc, Part, FaceToMachine, EdgeToMachine, Optional
    -- lunghezze e punti caratteristici della lavorazione e del lato lavorato
    Mortising.dLengthToMachine = dLengthToMachine
    -- TODO serve un modo migliore di calcolare la lunghezza lungo X; attenzione che serve la lunghezza reale di lavoro, non quella del lato
-   Mortising.dLengthOnX = abs( dLengthToMachine * EdgeToMachine.vtToolDirection:getY())
+   Mortising.dLengthOnX = abs( dLengthToMachine * EdgeToMachine.vtN:getY())
    Mortising.dEdgeLength = EdgeToMachine.dLength
-   Mortising.ptEdge1, _, Mortising.ptEdge2 = EgtSurfTmFacetOppositeSide( Proc.id, FaceToMachine.id, -EdgeToMachine.vtToolDirection, GDB_ID.ROOT)
-   Mortising.vtToolDirection = EdgeToMachine.vtToolDirection
+   Mortising.ptEdge1, _, Mortising.ptEdge2 = EgtSurfTmFacetOppositeSide( Proc.id, FaceToMachine.id, -EdgeToMachine.vtN, GDB_ID.ROOT)
+   Mortising.vtToolDirection = EdgeToMachine.vtN
    if EdgeToMachine.bIsOpen then
-      Mortising.vtEdgeDirection = -EdgeToMachine.vtToolDirection ^ FaceToMachine.vtN
+      Mortising.vtEdgeDirection = -EdgeToMachine.vtN ^ FaceToMachine.vtN
    else
-      Mortising.vtEdgeDirection = EdgeToMachine.vtToolDirection ^ FaceToMachine.vtN
+      Mortising.vtEdgeDirection = EdgeToMachine.vtN ^ FaceToMachine.vtN
    end
 
    -- ricerca utensile
@@ -101,7 +101,7 @@ function SLOTBYCHAINSAW.Make( Proc, Part, FaceToMachine, EdgeToMachine, Optional
    end
    local ToolSearchParameters = {}
    local ToolInfo = {}
-   ToolSearchParameters.vtToolDirection = EdgeToMachine.vtToolDirection
+   ToolSearchParameters.vtToolDirection = EdgeToMachine.vtN
    ToolSearchParameters.bAllowTopHead = true
    ToolSearchParameters.bAllowBottomHead = true
    ToolSearchParameters.dElevation = Mortising.dDepthToMachine
@@ -194,20 +194,20 @@ function SLOTBYCHAINSAW.Make( Proc, Part, FaceToMachine, EdgeToMachine, Optional
    Mortising.Steps.dStep = TOOLS[Mortising.nToolIndex].dStep
    -- faceuse
    if EdgeToMachine.dElevation > - 10 * GEO.EPS_SMALL then
-      Mortising.nFaceuse = BeamLib.GetNearestParalOpposite( EdgeToMachine.vtToolDirection)
+      Mortising.nFaceuse = BeamLib.GetNearestParalOpposite( EdgeToMachine.vtN)
    else
-      Mortising.nFaceuse = BeamLib.GetNearestParalOpposite( -EdgeToMachine.vtToolDirection)
+      Mortising.nFaceuse = BeamLib.GetNearestParalOpposite( -EdgeToMachine.vtN)
    end
    -- SCC
    Mortising.SCC = MCH_SCC.NONE
    -- asse bloccato e angoli suggeriti
-   local vtRes = FaceToMachine.vtN ^ EdgeToMachine.vtToolDirection
+   local vtRes = FaceToMachine.vtN ^ EdgeToMachine.vtN
    if abs( vtRes:getZ()) < 10 * GEO.EPS_SMALL then
       Mortising.sBlockedAxis = BeamLib.GetBlockedAxis( Mortising.nToolIndex, 'perpendicular', Part.b3Raw, FaceToMachine.vtN)
-      Mortising.sSuggestedAngles = BeamLib.GetChainSawInitAngs( FaceToMachine.vtN, EdgeToMachine.vtToolDirection, 1)
-   elseif EdgeToMachine.vtToolDirection:getZ() < 10 * GEO.EPS_SMALL then
+      Mortising.sSuggestedAngles = BeamLib.GetChainSawInitAngs( FaceToMachine.vtN, EdgeToMachine.vtN, 1)
+   elseif EdgeToMachine.vtN:getZ() < 10 * GEO.EPS_SMALL then
       Mortising.sBlockedAxis = BeamLib.GetBlockedAxis( Mortising.nToolIndex, 'parallel', Part.b3Raw, FaceToMachine.vtN)
-      Mortising.sSuggestedAngles = BeamLib.GetChainSawInitAngs( FaceToMachine.vtN, EdgeToMachine.vtToolDirection, 2)
+      Mortising.sSuggestedAngles = BeamLib.GetChainSawInitAngs( FaceToMachine.vtN, EdgeToMachine.vtN, 2)
    end
    -- approccio e retrazione
    Mortising.LeadIn, Mortising.LeadOut = CalculateLeadInOut( Mortising, EdgeToMachine, sSideToMachine, dLengthToMachine)
@@ -220,7 +220,7 @@ function SLOTBYCHAINSAW.Make( Proc, Part, FaceToMachine, EdgeToMachine, Optional
 
    -- se lavorazione aperta sulla coda, eventuali aggiustamenti
    -- TODO valutare se fare funzione a parte
-   if Proc.AffectedFaces.bLeft and ( EdgeToMachine.sType == 'Bottom' or ( EdgeToMachine.vtToolDirection:getX() < 0.707)) then
+   if Proc.AffectedFaces.bLeft and ( EdgeToMachine.sType == 'Bottom' or ( EdgeToMachine.vtN:getX() < 0.707)) then
       local dLengthOnX = Mortising.dLengthOnX
       -- se feature splittata non si considera la lunghezza della feature per il check spostamento dopo separazione
       if bIsSplitFeature then
@@ -231,7 +231,7 @@ function SLOTBYCHAINSAW.Make( Proc, Part, FaceToMachine, EdgeToMachine, Optional
       if bStartLeft then
          dAddLengthLeftSide = Mortising.LeadIn.dStartAddLength
       end
-      if not AreSameOrOppositeVectorApprox( EdgeToMachine.vtToolDirection, Y_AX()) then
+      if not AreSameOrOppositeVectorApprox( EdgeToMachine.vtN, Y_AX()) then
          if MachiningLib.CanMoveAfterSplitcut( dLengthOnX, Part) then
             Mortising.sStage = 'AfterTail'
          else
diff --git a/StrategyLibs/SPLITCUT.lua b/StrategyLibs/SPLITCUT.lua
index 8d68db5..d56cab5 100644
--- a/StrategyLibs/SPLITCUT.lua
+++ b/StrategyLibs/SPLITCUT.lua
@@ -185,7 +185,7 @@ function SPLITCUT.GetStrategy( Proc, Part, OptionalParameters)
 function SPLITCUT.GetEdgeToMachine( Proc, vtEdge)
    local Edge
    for i = 1, #Proc.Faces[1].Edges do
-      if AreSameVectorApprox( Proc.Faces[1].Edges[i].vtToolDirection, vtEdge) then
+      if AreSameVectorApprox( Proc.Faces[1].Edges[i].vtN, vtEdge) then
          Edge = Proc.Faces[1].Edges[i]
       end
    end