diff --git a/LuaLibs/ProcessLongDoubleCut.lua b/LuaLibs/ProcessLongDoubleCut.lua
index 0ca28ce..a93ac44 100644
--- a/LuaLibs/ProcessLongDoubleCut.lua
+++ b/LuaLibs/ProcessLongDoubleCut.lua
@@ -1334,7 +1334,7 @@ function ProcessLong2Cut.Make( Proc, nPhase, nRawId, nPartId, bForcedBladeMaster
                          nSCC = EgtIf( nSide == -1, MCH_SCC.ADIR_ZM, MCH_SCC.ADIR_ZP)
                      end
                   else
-                     local bFromZM = (( vtN[vOrd[i]]:getZ() < 0 and bConvex) or ( vtN[vOrd[i]]:getZ() > 0 and not bConvex))
+                     local bFromZM = (( vtN[vOrd[i]]:getZ() < 10 * GEO.EPS_ANG_SMALL and bConvex) or ( vtN[vOrd[i]]:getZ() > - 10 * GEO.EPS_ANG_SMALL and not bConvex))
                      nSCC = EgtIf( bFromZM, MCH_SCC.ADIR_ZM, MCH_SCC.ADIR_ZP)
                   end
                end