diff --git a/LuaLibs/ProcessCut.lua b/LuaLibs/ProcessCut.lua
index 3071633..96d54ba 100644
--- a/LuaLibs/ProcessCut.lua
+++ b/LuaLibs/ProcessCut.lua
@@ -400,9 +400,12 @@ local function MakeFromTop( sCutting, Proc, nPhase, nRawId, nPartId, dOvmHead, b
    local bDangerousReliefCut = false
    local frFace = BL.GetFaceHvRefDim( Proc.Id, 0)
    -- verifico che i tagli perpendicolari siano perpendicolari al lato più vicino a Z
-   local vtTemp = EgtSurfTmFacetNormVersor( vCuts[1][1], 0, GDB_ID.ROOT) ^ frFace:getVersY()
-   if #vCuts > 0 and vtTemp:isSmall() and not ( bDownCut or bFromBottom) then
-      bDangerousReliefCut = true
+   local nFirstPerpendicularCut = ( #vCuts ~= 0 and ( vCuts[1][1] or vCuts[3][1]))
+   if nFirstPerpendicularCut then
+      local vtTemp = EgtSurfTmFacetNormVersor( nFirstPerpendicularCut, 0, GDB_ID.ROOT) ^ frFace:getVersY()
+      if #vCuts > 0 and vtTemp:isSmall() and not ( bDownCut or bFromBottom) then
+         bDangerousReliefCut = true
+      end
    end
 
    --DC.PrintOrderCut( vCuts)