Index: Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Calculators/UpliftVan/UpliftVanCalculator.cs
===================================================================
diff -u -rda5614e4f69e43e5ae930bf74fb76a6d2d00058d -r9bb52a5c5ee233271ee2f3e6f1e62437b105762e
--- Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Calculators/UpliftVan/UpliftVanCalculator.cs	(.../UpliftVanCalculator.cs)	(revision da5614e4f69e43e5ae930bf74fb76a6d2d00058d)
+++ Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Calculators/UpliftVan/UpliftVanCalculator.cs	(.../UpliftVanCalculator.cs)	(revision 9bb52a5c5ee233271ee2f3e6f1e62437b105762e)
@@ -121,6 +121,10 @@
             SurfaceLine2 surfaceLine2 = SurfaceLineCreator.Create(input.SurfaceLine);
             SoilProfile2D soilProfile2D = SoilProfileCreator.Create(input.SoilProfile.PreconsolidationStresses, layersWithSoil);
 
+            upliftVanKernel.SetSlipPlaneUpliftVan(SlipPlaneUpliftVanCreator.Create(input.SlipPlane));
+            upliftVanKernel.SetSlipPlaneConstraints(SlipPlaneConstraintsCreator.Create(input.SlipPlaneConstraints));
+            upliftVanKernel.SetGridAutomaticDetermined(input.SlipPlane.GridAutomaticDetermined);
+            upliftVanKernel.SetTangentLinesAutomaticDetermined(input.SlipPlane.TangentLinesAutomaticAtBoundaries);
             upliftVanKernel.SetMoveGrid(input.MoveGrid);
             upliftVanKernel.SetMaximumSliceWidth(input.MaximumSliceWidth);
             upliftVanKernel.SetSurfaceLine(surfaceLine2);
@@ -140,11 +144,7 @@
             waternetExtremeKernelWrapper.SetSurfaceLine(surfaceLine2);
             waternetExtremeKernelWrapper.Calculate();
             upliftVanKernel.SetWaternetExtreme(waternetExtremeKernelWrapper.Waternet);
-
-            upliftVanKernel.SetSlipPlaneUpliftVan(SlipPlaneUpliftVanCreator.Create(input.SlipPlane));
-            upliftVanKernel.SetSlipPlaneConstraints(SlipPlaneConstraintsCreator.Create(input.SlipPlaneConstraints));
-            upliftVanKernel.SetGridAutomaticDetermined(input.SlipPlane.GridAutomaticDetermined);
-
+            
             return upliftVanKernel;
         }
     }
Index: Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/IUpliftVanKernel.cs
===================================================================
diff -u -r3a03f421a9936d6b23596533aa1d130485ea41e7 -r9bb52a5c5ee233271ee2f3e6f1e62437b105762e
--- Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/IUpliftVanKernel.cs	(.../IUpliftVanKernel.cs)	(revision 3a03f421a9936d6b23596533aa1d130485ea41e7)
+++ Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/IUpliftVanKernel.cs	(.../IUpliftVanKernel.cs)	(revision 9bb52a5c5ee233271ee2f3e6f1e62437b105762e)
@@ -128,6 +128,11 @@
         void SetGridAutomaticDetermined(bool gridAutomaticDetermined);
 
         /// <summary>
+        /// Sets whether the tangent lines are automatically determined or not.
+        /// </summary>
+        void SetTangentLinesAutomaticDetermined(bool slipPlaneTangentLinesAutomaticAtBoundaries);
+
+        /// <summary>
         /// Performs the Uplift Van calculation.
         /// </summary>
         /// <exception cref="UpliftVanKernelWrapperException">Thrown when
Index: Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/UpliftVanKernelWrapper.cs
===================================================================
diff -u -r0aa21164a7e21de370e4f301103d020fbeb2966c -r9bb52a5c5ee233271ee2f3e6f1e62437b105762e
--- Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/UpliftVanKernelWrapper.cs	(.../UpliftVanKernelWrapper.cs)	(revision 0aa21164a7e21de370e4f301103d020fbeb2966c)
+++ Riskeer/MacroStabilityInwards/src/Riskeer.MacroStabilityInwards.KernelWrapper/Kernels/UpliftVan/UpliftVanKernelWrapper.cs	(.../UpliftVanKernelWrapper.cs)	(revision 9bb52a5c5ee233271ee2f3e6f1e62437b105762e)
@@ -70,14 +70,6 @@
             ForbiddenZonesXEntryMax = double.NaN;
         }
 
-        private void AddPreProcessingConstructionStages()
-        {
-            kernelModel.PreprocessingModel.PreProcessingConstructionStages.Add(new PreprocessingConstructionStage
-            {
-                StabilityModel = kernelModel.StabilityModel
-            });
-        }
-
         public double FactorOfStability { get; private set; }
 
         public double ZValue { get; private set; }
@@ -127,6 +119,11 @@
             kernelModel.PreprocessingModel.SearchAreaConditions.AutoSearchArea = gridAutomaticDetermined;
         }
 
+        public void SetTangentLinesAutomaticDetermined(bool tangentLinesAutomaticDetermined)
+        {
+            kernelModel.PreprocessingModel.SearchAreaConditions.AutoTangentLines = tangentLinesAutomaticDetermined;
+        }
+
         public void SetSoilModel(IList<Soil> soilModel)
         {
             kernelModel.StabilityModel.Soils.AddRange(soilModel);
@@ -162,6 +159,12 @@
         {
             try
             {
+                // The following lines are necessary as a workaround for the kernel.
+                // The kernel validates before generating the grid, with calling Update, this is prevented.
+                PreprocessingModel preprocessingModel = kernelModel.PreprocessingModel;
+                var preprocessor = new StabilityPreprocessor();
+                preprocessor.Update(kernelModel.StabilityModel, preprocessingModel);
+
                 IValidationResult[] validationResults = Validator.Validate(kernelModel);
                 return validationResults;
             }
@@ -171,6 +174,14 @@
             }
         }
 
+        private void AddPreProcessingConstructionStages()
+        {
+            kernelModel.PreprocessingModel.PreProcessingConstructionStages.Add(new PreprocessingConstructionStage
+            {
+                StabilityModel = kernelModel.StabilityModel
+            });
+        }
+
         private void ReadLogMessages(List<LogMessage> kernelCalculationLogMessages)
         {
             CalculationMessages = kernelCalculationLogMessages ?? Enumerable.Empty<LogMessage>();
Index: Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.Test/Kernels/UpliftVan/UpliftVanKernelWrapperTest.cs
===================================================================
diff -u -r0aa21164a7e21de370e4f301103d020fbeb2966c -r9bb52a5c5ee233271ee2f3e6f1e62437b105762e
--- Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.Test/Kernels/UpliftVan/UpliftVanKernelWrapperTest.cs	(.../UpliftVanKernelWrapperTest.cs)	(revision 0aa21164a7e21de370e4f301103d020fbeb2966c)
+++ Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.Test/Kernels/UpliftVan/UpliftVanKernelWrapperTest.cs	(.../UpliftVanKernelWrapperTest.cs)	(revision 9bb52a5c5ee233271ee2f3e6f1e62437b105762e)
@@ -210,13 +210,13 @@
         public void Validate_InvalidInput_GeneratesValidationMessages()
         {
             // Setup
-            UpliftVanKernelWrapper kernel = CreateInvalidKernel(null);
+            UpliftVanKernelWrapper kernel = CreateInvalidKernel(new Soil());
 
             // Call
             var validationMessages = kernel.Validate();
 
             // Assert
-            Assert.AreEqual(13, validationMessages.Count());
+            Assert.AreEqual(12, validationMessages.Count());
         }
 
         private static UpliftVanKernelWrapper CreateValidKernel(Soil soil)
Index: Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.TestUtil/Kernels/UpliftVan/UpliftVanKernelStub.cs
===================================================================
diff -u -r3a03f421a9936d6b23596533aa1d130485ea41e7 -r9bb52a5c5ee233271ee2f3e6f1e62437b105762e
--- Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.TestUtil/Kernels/UpliftVan/UpliftVanKernelStub.cs	(.../UpliftVanKernelStub.cs)	(revision 3a03f421a9936d6b23596533aa1d130485ea41e7)
+++ Riskeer/MacroStabilityInwards/test/Riskeer.MacroStabilityInwards.KernelWrapper.TestUtil/Kernels/UpliftVan/UpliftVanKernelStub.cs	(.../UpliftVanKernelStub.cs)	(revision 9bb52a5c5ee233271ee2f3e6f1e62437b105762e)
@@ -24,7 +24,6 @@
 using Deltares.MacroStability.Data;
 using Deltares.MacroStability.Geometry;
 using Deltares.MacroStability.Standard;
-using Deltares.MacroStability.WaternetCreator;
 using Riskeer.MacroStabilityInwards.KernelWrapper.Kernels.UpliftVan;
 using WtiStabilityWaternet = Deltares.MacroStability.Geometry.Waternet;
 
@@ -81,6 +80,8 @@
 
         public bool GridAutomaticDetermined { get; private set; }
 
+        public bool TangentLinesAutomaticDetermined { get; private set; }
+
         public WtiStabilityWaternet WaternetDaily { get; private set; }
 
         public WtiStabilityWaternet WaternetExtreme { get; private set; }
@@ -149,6 +150,11 @@
             GridAutomaticDetermined = gridAutomaticDetermined;
         }
 
+        public void SetTangentLinesAutomaticDetermined(bool slipPlaneTangentLinesAutomaticAtBoundaries)
+        {
+            TangentLinesAutomaticDetermined = slipPlaneTangentLinesAutomaticAtBoundaries;
+        }
+
         public void Calculate()
         {
             if (ThrowExceptionOnCalculate)