diff --git a/LuaLibs/PreSimulationLib.lua b/LuaLibs/PreSimulationLib.lua
index 869ba1f..84cc3ad 100644
--- a/LuaLibs/PreSimulationLib.lua
+++ b/LuaLibs/PreSimulationLib.lua
@@ -65,13 +65,21 @@ local function LogOutstroke( ptOnToolTipCenter, vtHead, OptionalParameters)
 end
 
 -------------------------------------------------------------------------------------------------------------
--- costruzione trimesh del grezzo restante (con leggera sovrapposizione)
-local function GetRestlengthSurfTm( Part)
-   
+-- costruzione trimesh del grezzo restante in testa o in coda (con leggera sovrapposizione)
+local function GetRestlengthSurfTm( Part, sRestLengthSideForPreSimulation)
+
    -- si costruisce il box in globale
-   local ptRestLengthMax = Point3d( Part.b3Part:getMin()) + X_AX() * 500 * GEO.EPS_SMALL
-   local ptRestLengthMin = Point3d( Part.b3Part:getMin():getX() - Part.dRestLength, Part.b3Part:getMax():getY(), Part.b3Part:getMax():getZ())
-   local b3RestLength = BBox3d( ptRestLengthMin, ptRestLengthMax)
+   local b3RestLength = BBox3d()
+   if sRestLengthSideForPreSimulation == 'Tail' then
+      local ptRestLengthMax = Point3d( Part.b3Part:getMin()) + X_AX() * 500 * GEO.EPS_SMALL
+      local ptRestLengthMin = Point3d( Part.b3Part:getMin():getX() - Part.dRestLength, Part.b3Part:getMax():getY(), Part.b3Part:getMax():getZ())
+      b3RestLength = BBox3d( ptRestLengthMin, ptRestLengthMax)
+   elseif sRestLengthSideForPreSimulation == 'Head' then
+      local ptRestLengthMin = Point3d( Part.b3Part:getMax() - X_AX() * 500 * GEO.EPS_SMALL)
+      local ptRestLengthMax = Point3d( Part.b3Part:getMaX():getX() + Part.dHeadOverMaterial, Part.b3Part:getMin():getY(), Part.b3Part:getMin():getZ())
+      b3RestLength = BBox3d( ptRestLengthMin, ptRestLengthMax)
+   end
+
    -- si crea la trimesh dal box
    local idRestLengthBoxTm = EgtSurfTmBBox( Part.idTempGroup, b3RestLength , false, GDB_RT.GLOB)
 
@@ -263,7 +271,7 @@ function PreSimulationLib.CheckOutOfStrokeFromGeometry( idGeometry, vtHead, nSCC
 end
 
 -------------------------------------------------------------------------------------------------------------
-local function CheckCollisionPoint( ptToolExitToCheck, vtC, vtHead, PreCollisionData, Part, bCheckOnlyRestlength)
+local function CheckCollisionPoint( ptToolExitToCheck, vtC, vtHead, PreCollisionData, Part, sRestLengthSideForPreSimulation, bCheckOnlyRestlength)
 
    local ptPivot = GetGlobalPivot( ptToolExitToCheck, vtC, vtHead, PreCollisionData.vtMovePivot)
 
@@ -311,7 +319,7 @@ local function CheckCollisionPoint( ptToolExitToCheck, vtC, vtHead, PreCollision
    -- check collisione con grezzo restante, se con il pezzo non c'è collisione
    local bCollisionFoundRestLength = false
    if not bCollisionFoundPiece then
-      local idRestLengthSurfFr = GetRestlengthSurfTm( Part)
+      local idRestLengthSurfFr = GetRestlengthSurfTm( Part, sRestLengthSideForPreSimulation)
       bCollisionFoundRestLength = EgtTestSurfaceSurface( idRestLengthSurfFr, idCollisionSurfTm, BeamData.COLL_SIC)
       if not type( bCollisionFoundRestLength) == "boolean" then
          error( 'EgtTestSurfaceSurface fail')
@@ -339,21 +347,14 @@ local function CheckCollisionWithAxis( sAxis, MachiningParameters, OptionalParam
    -- parametri opzionali
    OptionalParameters = OptionalParameters or {}
    local bCheckOnlyRestlength = OptionalParameters.bCheckOnlyRestlength or false
+   local sRestLengthSideForPreSimulation = OptionalParameters.sRestLengthSideForPreSimulation or 'Tail'
+   local bCannotSplitRestLength = OptionalParameters.bCannotSplitRestLength or false
 
    -- se normale faccia non parallela a direzione testa c'è qualcosa che non va
    if not AreSameOrOppositeVectorApprox( vtNFace, vtHead) then
       error( 'CheckCollisionWithAxis : invalid directions')
    end
-
-   -- TODO modificare e rimettere (Hmax pezzo)
-   -- se direzione utensile parallela ad uno degli assi principali non serve alcuna verifica
-   -- if AreSameOrOppositeVectorApprox( Edge.vtN, X_AX())
-   --    or AreSameOrOppositeVectorApprox( Edge.vtN, Y_AX())
-   --    or AreSameOrOppositeVectorApprox( Edge.vtN, Z_AX()) then
-         
-   --    return false
-   -- end
-
+   
    -- punti notevoli della lavorazione in cui fare il check
    local PointsToCheck = OptionalParameters.PointsToCheck or GetCollisionPointsToCheck( Edge, dDepthToMachine)
 
@@ -384,10 +385,10 @@ local function CheckCollisionWithAxis( sAxis, MachiningParameters, OptionalParam
    -- se non si trova collisione si ritorna se è necessario separare prima di effettuare la lavorazione (ossia non c'è collisione con il pezzo ma c'è con il grezzo restante)
    for i = 1, #ToolExitPoints do
 
-      local bCollisionFoundPiece, bCollisionFoundRestLength = CheckCollisionPoint( ToolExitPoints[i], vtC, vtHead, PreCollisionData, Part, bCheckOnlyRestlength)
+      local bCollisionFoundPiece, bCollisionFoundRestLength = CheckCollisionPoint( ToolExitPoints[i], vtC, vtHead, PreCollisionData, Part, sRestLengthSideForPreSimulation, bCheckOnlyRestlength)
 
-      -- se trovata collisione con pezzo è inutile controllare gli altri punti
-      if bCollisionFoundPiece then
+      -- se trovata collisione con pezzo oppure non possibile separazione, è inutile controllare gli altri punti
+      if bCollisionFoundPiece or ( bCannotSplitRestLength and bCollisionFoundRestLength) then
 
          return true
 
@@ -414,6 +415,8 @@ function PreSimulationLib.CheckCollision( sBladeEngagement, Parameters, Optional
    local OptionalParametersCheckCollisionWithAxis = {}
    OptionalParametersCheckCollisionWithAxis.bCheckOnlyRestlength = false
    OptionalParametersCheckCollisionWithAxis.PointsToCheck = OptionalParameters.PointsToCheck or nil
+   OptionalParametersCheckCollisionWithAxis.sRestLengthSideForPreSimulation = OptionalParameters.sRestLengthSideForPreSimulation or 'Tail'
+   OptionalParametersCheckCollisionWithAxis.bCannotSplitRestLength = OptionalParameters.bCannotSplitRestLength or false
 
    local bIsDicing = OptionalParameters.bIsDicing or false
    local bCheckOnlyRestlengthForAxisABC = false
diff --git a/StrategyLibs/FACEBYBLADE.lua b/StrategyLibs/FACEBYBLADE.lua
index 6fe0661..a503791 100644
--- a/StrategyLibs/FACEBYBLADE.lua
+++ b/StrategyLibs/FACEBYBLADE.lua
@@ -203,6 +203,8 @@ function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
    local dRadialStepSpan = OptionalParameters.dRadialStepSpan
    local sUserNotes = OptionalParameters.sUserNotes or ''
    local bIsDicing = OptionalParameters.bIsDicing or false
+   local sRestLengthSideForPreSimulation = OptionalParameters.sRestLengthSideForPreSimulation or 'Tail'
+   local bCannotSplitRestLength = OptionalParameters.bCannotSplitRestLength or false
 
    -- lunghezze, direzioni e punti caratteristici della lavorazione e del lato lavorato
    Cutting.dEdgeLength = EdgeToMachine.dLength
@@ -224,7 +226,9 @@ function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
          dDepthToMachine = dDepthToMachine
       }
       local BladeEngagementOptionalParameters = {
-         bIsDicing = bIsDicing
+         bIsDicing = bIsDicing,
+         sRestLengthSideForPreSimulation = sRestLengthSideForPreSimulation,
+         bCannotSplitRestLength = bCannotSplitRestLength
       }
       local Engagement
       TIMER:startElapsed( 'GetBladeEngagement')
@@ -246,6 +250,8 @@ function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
       ToolSearchParameters.FaceToMachine = FaceToMachine
       ToolSearchParameters.EdgeToMachine = EdgeToMachine
       ToolSearchParameters.Part = Part
+      ToolSearchParameters.sRestLengthSideForPreSimulation = sRestLengthSideForPreSimulation
+      ToolSearchParameters.bCannotSplitRestLength = bCannotSplitRestLength
 
       local ToolInfo = MachiningLib.FindBlade( Proc, ToolSearchParameters)
       Cutting.nToolIndex = ToolInfo.nToolIndex
@@ -340,7 +346,9 @@ function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
          dDepthToMachine = dDepthToMachine
       }
       local BladeEngagementOptionalParameters = {
-         bIsDicing = bIsDicing
+         bIsDicing = bIsDicing,
+         sRestLengthSideForPreSimulation = sRestLengthSideForPreSimulation,
+         bCannotSplitRestLength = bCannotSplitRestLength
       }
       TIMER:startElapsed( 'GetBladeEngagement')
       local bIsApplicableOpposite, EngagementOpposite = MachiningLib.GetBladeEngagement( BladeEngagementParameters, BladeEngagementOptionalParameters)
@@ -455,7 +463,9 @@ function FACEBYBLADE.Make( Proc, Part, FaceToMachine, EdgeToMachine, OptionalPar
             dDepthToMachine = dDepthToMachine
          }
          local BladeEngagementOptionalParameters = {
-            bIsDicing = bIsDicing
+            bIsDicing = bIsDicing,
+            sRestLengthSideForPreSimulation = sRestLengthSideForPreSimulation,
+            bCannotSplitRestLength = bCannotSplitRestLength
          }
          TIMER:startElapsed( 'GetBladeEngagement')
          local bIsApplicable, CurrentEngagement = MachiningLib.GetBladeEngagement( BladeEngagementParameters, BladeEngagementOptionalParameters )