diff --git a/Designing/WinLib/WinCalculate.lua b/Designing/WinLib/WinCalculate.lua
index cc4d8de..49ba54f 100644
--- a/Designing/WinLib/WinCalculate.lua
+++ b/Designing/WinLib/WinCalculate.lua
@@ -6462,7 +6462,7 @@ local function CalcPartPreview( nPartId, nPreviewGrp)
             local dRailDelta = EgtGetInfo( vStartProfiles[i], WIN_RAILDELTA, 'd') or 0
             local dOffs = b3Profile:getMin():getX() - dRailDelta
             if vPrevOutlines[i] < 0 then
-               EgtInvert( nCrv)
+               EgtInvertCurve( nCrv)
                dOffs = - ( b3Profile:getMax():getX() - dRailDelta)
             end
             EgtOffsetCurve( nCrv, dOffs)