diff --git a/LuaLibs/CalcPaths.lua b/LuaLibs/CalcPaths.lua
index b7e4e35..53d63ed 100644
--- a/LuaLibs/CalcPaths.lua
+++ b/LuaLibs/CalcPaths.lua
@@ -946,10 +946,11 @@ local function CreateShellNbrSurfaces( nGrp, nShellsNbr)
          end
       end
       -- costruisco la surf
-      local nSrfId, nCnt = EgtSurfFlatRegion( nSrfGrp, vCrvIds)
-      for nIdSrf = nSrfId + 1, nSrfId + nCnt - 1 do
-         EgtSurfFrAdd( nSrfId, nIdSrf)
-         EgtErase( nIdSrf)
+      local nSrfId = EgtSurfFlatRegion( nSrfGrp, vCrvIds[1])
+      for i = 2, #vCrvIds do
+         local nSrfTmp = EgtSurfFlatRegion( nSrfGrp, vCrvIds[i])
+         EgtSurfFrAdd( nSrfId, nSrfTmp)
+         EgtErase( nSrfTmp)
       end
       EgtSetName( nSrfId, SHELL_NBR_SURF .. tostring( nDiff))
    end
diff --git a/LuaLibs/CalcToolPath.lua b/LuaLibs/CalcToolPath.lua
index fb027a4..02f1714 100644
--- a/LuaLibs/CalcToolPath.lua
+++ b/LuaLibs/CalcToolPath.lua
@@ -996,9 +996,9 @@ function CalcToolPath.Exec( nPartId)
             -- recupero i parametri
             local nType = EgtGetInfo( nId, KEY_TYPE, 'i')
             local bClosed = EgtGetInfo( nId, KEY_CLOSED_CRV, 'b') or false
-            local dCoastingLen = EgtIf( nType == TYPE.EXTRA_SHELL and not bClosed, LayerParams.dShellNbrCoasting, LayerParams.dCoastingLen)
-            local dWipeLen = EgtIf( nType == TYPE.EXTRA_SHELL and not bClosed, LayerParams.dShellNbrWipe, LayerParams.dWipeLen)
-            local dWipeDir = EgtIf( nType == TYPE.EXTRA_SHELL and not bClosed, LayerParams.dShellNbrWipeDir, 0)
+            local dCoastingLen = EgtIf( ( nType == TYPE.EXTRA_SHELL or nType == TYPE.EXTRA_OUTER_SHELL) and not bClosed, LayerParams.dShellNbrCoasting, LayerParams.dCoastingLen)
+            local dWipeLen = EgtIf( ( nType == TYPE.EXTRA_SHELL or nType == TYPE.EXTRA_OUTER_SHELL) and not bClosed, LayerParams.dShellNbrWipe, LayerParams.dWipeLen)
+            local dWipeDir = EgtIf( ( nType == TYPE.EXTRA_SHELL or nType == TYPE.EXTRA_OUTER_SHELL) and not bClosed, LayerParams.dShellNbrWipeDir, 0)
             
             if nId == nLastId then
                AddRetractionOnLastCrv( nId, nTpathGrpId, LayerParams, dCoastingLen, dWipeLen, dWipeDir)