Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs
===================================================================
diff -u -r4994 -r4995
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs	(.../MacroStabilityCommonHelperTests.cs)	(revision 4994)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs	(.../MacroStabilityCommonHelperTests.cs)	(revision 4995)
@@ -118,6 +118,32 @@
         });
     }
 
+    [Test]
+    public void GivenSoilGeometryProbabilityWithSoilProfile2DAndMatchingSurfaceLineLongerOnLeftWhenCombiningThenSoilProfile2DIsExtendedToTheLeft()
+    {
+        SoilGeometryProbability soilGeometryProbability = CreateSoilGeometryProbabilityWithSoilProfile2DWithSurfaceLineDitchDike();
+        // Create the same surfaceline as is used for creating the SoilProfile2D in the SoilGeometryProbability
+        // But now the SurfaceLine2 is longer on the left side (-5.0 instead of 0.0)
+        SurfaceLine2 surfaceLine = FactoryForSurfaceLines.CreateSurfaceLineWithDikeAndDitch();
+        surfaceLine.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelOutside).X =
+            surfaceLine.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelOutside).X - 5.0;
+        // Now combine the soilGeometryProbability with the same SurfaceLine2 which should result the SoilProfile2D
+        // being extended to the left with 5.0 meters
+        MacroStabilityCommonHelper.CombineSoilProfileWithSurfaceLine(soilGeometryProbability, surfaceLine, new Soil());
+        GeometryData geometry = soilGeometryProbability.SoilProfile2D.Geometry;
+        // For debugging purposes
+        // GeometryExporter.ExportToFile(geometry, visualizationFolder + "Geometry.txt");
+        // GeometryExporter.ExportToJsonFile(geometry, visualizationFolder + "Geometry.json");
+        Assert.Multiple(() =>
+        {
+            Assert.That(soilGeometryProbability.SoilProfileType, Is.EqualTo(SoilProfileType.ProfileType2D));
+            Assert.That(geometry.Surfaces, Has.Count.EqualTo(2));
+            Assert.That(geometry.Left, Is.EqualTo(-5.0).Within(cTolerance));
+            Assert.That(geometry.Right, Is.EqualTo(75.0).Within(cTolerance));
+            Assert.That(geometry.Bottom, Is.EqualTo(-20.0).Within(cTolerance));
+        });
+    }
+
     private SoilGeometryProbability CreateSoilGeometryProbabilityWithSoilProfile2DWithSurfaceLineDitchDike()
     {
         SoilGeometryProbability soilGeometryProbability = FactoryForSoilGeometryProbabilities.CreateSoilGeometryProbabilityWithSoilProfile1D();
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs
===================================================================
diff -u -r4994 -r4995
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs	(.../MacroStabilityCommonHelper.cs)	(revision 4994)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs	(.../MacroStabilityCommonHelper.cs)	(revision 4995)
@@ -431,6 +431,11 @@
         {
             GeometryHelper.CutGeometryLeft(subSoilScenario.SoilProfile2D.Geometry, surfaceLine2LeftX);
         }
+
+        if (surfaceLine2LeftX < subSoilScenario.SoilProfile2D.Geometry.GetGeometryBounds().Left)
+        {
+            GeometryHelper.ExtendGeometryLeft(subSoilScenario.SoilProfile2D.Geometry, surfaceLine2LeftX);
+        }
     }
 
     /// <summary>