diff --git a/src/geouned/GEOUNED/Conversion/CellDefinition.py b/src/geouned/GEOUNED/Conversion/CellDefinition.py
index ca390815..9d2762c6 100644
--- a/src/geouned/GEOUNED/Conversion/CellDefinition.py
+++ b/src/geouned/GEOUNED/Conversion/CellDefinition.py
@@ -598,7 +598,7 @@ def GenTorusAnnexVSurface(face,Vparams,forceCylinder=False):
        Apex   = face.Surface.Center + za * axis
        semiAngle = abs(math.atan(d1/(z1-za)))
 
-       ConeAxis = axis if za < 0 else -axis
+       ConeAxis = axis if (z1 - za) > 0.0 else -axis
 
        Vmid = (Vparams[0]+Vparams[1])*0.5
        pMid = face.valueAt(0,Vmid) - face.Surface.Center