Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs
===================================================================
diff -u -r5404 -r5436
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 5404)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 5436)
@@ -578,19 +578,21 @@
     /// </summary>
     internal static void AvoidUpwardsVerticalLine(IList<Point2D> points)
     {
-        for (var i = 0; i < points.Count - 2; i++)
+        for (var i = 0; i < points.Count - 1; i++)
         {
-            if (Math.Abs(points[i].X - points[i + 1].X) < toleranceAlmostEqual && points[i].Z < points[i + 1].Z)
+            if (!(Math.Abs(points[i].X - points[i + 1].X) < toleranceAlmostEqual) || !(points[i].Z < points[i + 1].Z))
             {
-                if (points[i + 1].X + 0.01 < points[i + 2].X)
-                {
-                    points[i + 1].X += 0.01;
-                }
-                else
-                {
-                    points[i + 1].X = points[i + 2].X - (points[i + 2].X - points[i + 1].X) / 2;
-                }
+                continue;
             }
+            
+            if (i == points.Count - 2 || (points[i + 1].X + 0.01 < points[i + 2].X))
+            {
+                points[i + 1].X += 0.01;
+            }
+            else
+            {
+                points[i + 1].X = points[i + 2].X - (points[i + 2].X - points[i + 1].X) / 2;
+            }
         }
     }
 }
\ No newline at end of file