Index: DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/GeometryHelperTests.cs
===================================================================
diff -u -r4835 -r4837
--- DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/GeometryHelperTests.cs	(.../GeometryHelperTests.cs)	(revision 4835)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/GeometryHelperTests.cs	(.../GeometryHelperTests.cs)	(revision 4837)
@@ -43,4 +43,17 @@
         // Then
         Assert.That(soilProfile2D.Geometry.Left, Is.EqualTo(-2).Within(cTolerance));
     }
+    
+    [Test]
+    public void GivenTwoLayerGeometryWhenExtendingRigthThenLeftBoundaryIsChanged()
+    {
+        // Given
+        SoilProfile2D soilProfile2D = FactoryForSoilProfiles.CreateSoilProfile2DWithTwoLayers();
+
+        // When
+        GeometryHelper.ExtendGeometryLeft(soilProfile2D.Geometry, 12);
+
+        // Then
+        Assert.That(soilProfile2D.Geometry.Right, Is.EqualTo(12).Within(cTolerance));
+    }
 }
\ No newline at end of file
Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryHelper.cs
===================================================================
diff -u -r4835 -r4837
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryHelper.cs	(.../GeometryHelper.cs)	(revision 4835)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryHelper.cs	(.../GeometryHelper.cs)	(revision 4837)
@@ -30,6 +30,7 @@
     /// <summary>
     /// Extends the geometry left to the given value of x.
     /// </summary>
+    /// <param name="geometry">The geometry to extend</param>
     /// <param name="toX">The x position to move the boundary to.</param>
     public static void ExtendGeometryLeft(GeometryData geometry, double toX)
     {
@@ -63,4 +64,40 @@
         geometry.Rebox();
         geometry.Left = toX;
     }
+    /// <summary>
+    /// Extends the geometry right to the given value of x.
+    /// </summary>
+    /// <param name="geometry">The geometry to extend</param>
+    /// <param name="toX">The x position to move the boundary to.</param>
+    private static void ExtendGeometryRight(GeometryData geometry, double toX)
+    {
+        var rightPoints = geometry.GetRightPoints().OrderBy(x => x.Z).ToArray();
+        var rightCurves = geometry.GetRightCurves();
+        Point2D prevPoint = null;
+        for (int i = 0; i < rightPoints.Length; i++)
+        {
+            var newPoint = new Point2D(toX, rightPoints[i].Z);
+            geometry.Points.Add(newPoint);
+            var newhorizontalCurve = new GeometryCurve(rightPoints[i], newPoint);
+            geometry.Curves.Add(newhorizontalCurve);
+            if (i > 0)
+            {
+                var newVerticalCurve = new GeometryCurve(newPoint, prevPoint);
+                geometry.Curves.Add(newVerticalCurve);
+            }
+            prevPoint = newPoint;
+        }
+        foreach (var geometryCurve in rightCurves)
+        {
+            // check if curve is vertical, only then it is on the "old" boundary and needs to be deleted
+            if (Math.Abs(geometryCurve.HeadPoint.X - geometryCurve.EndPoint.X) < GeometryConstants.Accuracy)
+            {
+                geometry.DeleteCurve(geometryCurve, false);
+            }
+        }
+        geometry.Rebox();
+        geometry.Right = toX;
+    }
+
+    
 }
\ No newline at end of file
Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs
===================================================================
diff -u -r4835 -r4837
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs	(.../GeometryData.cs)	(revision 4835)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs	(.../GeometryData.cs)	(revision 4837)
@@ -669,7 +669,7 @@
     /// <summary>
     /// Gets all points on the Left boundary.
     /// </summary>
-    /// <returns></returns>
+    /// <returns>The points on the Left boundary</returns>
     public List<Point2D> GetLeftPoints()
     {
         List<Point2D> geometryPoints = Points.Where(gp => Math.Abs(gp.X - Left) < GeometryConstants.Accuracy).ToList();
@@ -679,8 +679,8 @@
     /// <summary>
     /// Gets all points on the Right boundary.
     /// </summary>
-    /// <returns></returns>
-    private List<Point2D> GetRightPoints()
+    /// <returns>The points on the Right boundary</returns>
+    public List<Point2D> GetRightPoints()
     {
         List<Point2D> geometryPoints = Points.Where(point => Math.Abs(point.X - Right) < GeometryConstants.Accuracy).ToList();
         return geometryPoints;
@@ -704,11 +704,31 @@
                 leftCurves.Add(geometryCurve);
             }
         }
-
         return leftCurves;
     }
 
     /// <summary>
+    /// Gets the right curves, i.e. all curves that are on or connected to the Right boundary.
+    /// </summary>
+    /// <returns>The right curves</returns>
+    public List<GeometryCurve> GetRightCurves()
+    {
+        var rightCurves = new List<GeometryCurve>();
+        foreach (var curve in Curves)
+        {
+            if (curve.HeadPoint.X <= Right && curve.EndPoint.X >= Right)
+            {
+                rightCurves.Add(curve);
+            }
+            else if (curve.HeadPoint.X >= Right && curve.EndPoint.X <= Right)
+            {
+                rightCurves.Add(curve);
+            }
+        }
+        return rightCurves;
+    }
+    
+    /// <summary>
     /// Gets the geometry bounds.
     /// </summary>
     /// <returns></returns>