diff --git a/Modules/SurfaceInterpolation/mitkClusteredPlaneSuggestionFilter.cpp b/Modules/SurfaceInterpolation/mitkClusteredPlaneSuggestionFilter.cpp
index 71432b3235..3ee86c6d59 100644
--- a/Modules/SurfaceInterpolation/mitkClusteredPlaneSuggestionFilter.cpp
+++ b/Modules/SurfaceInterpolation/mitkClusteredPlaneSuggestionFilter.cpp
@@ -1,84 +1,102 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 #include <mitkClusteredPlaneSuggestionFilter.h>
 
 #include <vtkSmartPointer.h>
 #include <vtkUnstructuredGrid.h>
 #include <vtkPointLocator.h>
 #include <vtkPolyVertex.h>
 
 #include <mitkPlaneFit.h>
 #include <mitkPointSet.h>
 #include <mitkUnstructuredGridClusteringFilter.h>
 
 
 mitk::ClusteredPlaneSuggestionFilter::ClusteredPlaneSuggestionFilter(): m_Meshing(false), m_MinPts(4), m_Eps(1.2)
 {
   this->m_MainCluster = mitk::UnstructuredGrid::New();
   this->m_GeoData = mitk::GeometryData::New();
 }
 
 mitk::ClusteredPlaneSuggestionFilter::~ClusteredPlaneSuggestionFilter(){}
 
 void mitk::ClusteredPlaneSuggestionFilter::GenerateData()
 {
   mitk::UnstructuredGrid::Pointer inpGrid = const_cast<mitk::UnstructuredGrid*>(this->GetInput());
 
+  if(inpGrid.IsNull())
+  {
+    MITK_ERROR << "Input or cast to UnstructuredGrid is null";
+    return;
+  }
+
   mitk::UnstructuredGridClusteringFilter::Pointer clusterFilter = mitk::UnstructuredGridClusteringFilter::New();
   clusterFilter->SetInput(inpGrid);
   clusterFilter->SetMeshing(false);
   clusterFilter->SetMinPts(4);
   clusterFilter->Seteps(1.2);
   clusterFilter->Update();
 
-  m_Clusters = clusterFilter->GetAllClusters();
-
   vtkSmartPointer< vtkUnstructuredGrid > vtkGrid = clusterFilter->GetOutput()->GetVtkUnstructuredGrid();
+
+  if(!vtkGrid)
+  {
+    MITK_ERROR << "vtkUnstructuredGrid output from clustering is null";
+    return;
+  }
+
   m_MainCluster->SetVtkUnstructuredGrid(vtkGrid);
+  m_Clusters = clusterFilter->GetAllClusters();
 
   //Generate a pointset from UnstructuredGrid for the PlaneFitFilter:
   mitk::PointSet::Pointer pointset = mitk::PointSet::New();
 
   for(int i=0; i<vtkGrid->GetNumberOfPoints();i++)
   {
     mitk::Point3D point;
     point[0] = vtkGrid->GetPoint(i)[0];
     point[1] = vtkGrid->GetPoint(i)[1];
     point[2] = vtkGrid->GetPoint(i)[2];
 
     pointset->InsertPoint(i,point);
   }
 
   mitk::PlaneFit::Pointer planeFilter = mitk::PlaneFit::New();
   planeFilter->SetInput(pointset);
   planeFilter->Update();
 
   m_GeoData = planeFilter->GetOutput();
 
+  if(m_GeoData.IsNull())
+  {
+    MITK_ERROR << "GeometryData output from PlaneFit filter is null";
+    return;
+  }
+
 //  mitk::PlaneGeometry* planeGeometry = dynamic_cast<mitk::PlaneGeometry*>( planeFilter->GetOutput()->GetGeometry());
 }
 
 void mitk::ClusteredPlaneSuggestionFilter::GenerateOutputInformation()
 {
   mitk::UnstructuredGrid::ConstPointer inputImage = this->GetInput();
 
   m_MainCluster = this->GetOutput();
 
   itkDebugMacro(<<"GenerateOutputInformation()");
 
   if(inputImage.IsNull()) return;
 }