diff --git a/Modules/Segmentation/Interactions/mitkPaintbrushTool.cpp b/Modules/Segmentation/Interactions/mitkPaintbrushTool.cpp
index 20cedfd42b..31d10d195b 100644
--- a/Modules/Segmentation/Interactions/mitkPaintbrushTool.cpp
+++ b/Modules/Segmentation/Interactions/mitkPaintbrushTool.cpp
@@ -1,428 +1,448 @@
 /*===================================================================
 
 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 "mitkPaintbrushTool.h"
 
 #include "mitkToolManager.h"
 #include "mitkOverwriteSliceImageFilter.h"
 #include "mitkBaseRenderer.h"
 #include "mitkImageDataItem.h"
 #include "ipSegmentation.h"
 
 #include "mitkLevelWindowProperty.h"
 
 #define ROUND(a)     ((a)>0 ? (int)((a)+0.5) : -(int)(0.5-(a)))
 
 int mitk::PaintbrushTool::m_Size = 1;
 
 mitk::PaintbrushTool::PaintbrushTool(int paintingPixelValue)
 :FeedbackContourTool("PressMoveReleaseWithCTRLInversionAllMouseMoves"),
  m_PaintingPixelValue(paintingPixelValue),
  m_LastContourSize(0) // other than initial mitk::PaintbrushTool::m_Size (around l. 28)
 {
   // great magic numbers
   CONNECT_ACTION( 80, OnMousePressed );
   CONNECT_ACTION( 90, OnMouseMoved );
   CONNECT_ACTION( 42, OnMouseReleased );
   CONNECT_ACTION( 49014, OnInvertLogic );
 
 
   m_MasterContour = Contour::New();
   m_MasterContour->Initialize();
   m_CurrentPlane = NULL;
 
   m_WorkingNode = DataNode::New();
   m_WorkingNode->SetProperty( "levelwindow", mitk::LevelWindowProperty::New( mitk::LevelWindow(0, 1) ) );
   m_WorkingNode->SetProperty( "binary", mitk::BoolProperty::New(true) );
 }
 
 mitk::PaintbrushTool::~PaintbrushTool()
 {
 }
 
 void mitk::PaintbrushTool::Activated()
 {
   Superclass::Activated();
   FeedbackContourTool::SetFeedbackContourVisible(true);
   SizeChanged.Send(m_Size);
 }
 
 void mitk::PaintbrushTool::Deactivated()
 {
   FeedbackContourTool::SetFeedbackContourVisible(false);
   if (m_ToolManager->GetDataStorage()->Exists(m_WorkingNode))
       m_ToolManager->GetDataStorage()->Remove(m_WorkingNode);
   Superclass::Deactivated();
   m_WorkingSlice = NULL;
   m_CurrentPlane = NULL;
 }
 
 void mitk::PaintbrushTool::SetSize(int value)
 {
   m_Size = value;
 }
 
 mitk::Point2D mitk::PaintbrushTool::upperLeft(mitk::Point2D p)
 {
    p[0] -= 0.5;
    p[1] += 0.5;
    return p;
 }
 
 
 void mitk::PaintbrushTool::UpdateContour(const StateEvent* stateEvent)
 {
   //MITK_INFO<<"Update...";
   // examine stateEvent and create a contour that matches the pixel mask that we are going to draw
   const PositionEvent* positionEvent = dynamic_cast<const PositionEvent*>(stateEvent->GetEvent());
   if (!positionEvent) return;
 
   // Get Spacing of current Slice
   //mitk::Vector3D vSpacing = m_WorkingSlice->GetSlicedGeometry()->GetGeometry2D(0)->GetSpacing();
 
   //
   // Draw a contour in Square according to selected brush size
   //
   int radius = (m_Size)/2;
+  float fradius = static_cast<float>(m_Size) / 2.0f;
+
   Contour::Pointer contourInImageIndexCoordinates = Contour::New();
   contourInImageIndexCoordinates->Initialize();
 
+  // estimate center point of the brush ( relative to the pixel the mouse points on )
+  // -- left upper corner for even sizes,
+  // -- midpoint for uneven sizes
+  mitk::Point2D centerCorrection;
+  centerCorrection.Fill(0);
+
+  // even --> correction of [+0.5, +0.5]
+  bool evenSize = ((m_Size % 2) == 0);
+  if( evenSize )
+  {
+    centerCorrection[0] += 0.5;
+    centerCorrection[1] += 0.5;
+  }
+
 
   // we will compute the control points for the upper left quarter part of a circle contour
   std::vector< mitk::Point2D > quarterCycleUpperRight;
   std::vector< mitk::Point2D > quarterCycleLowerRight;
   std::vector< mitk::Point2D > quarterCycleLowerLeft;
   std::vector< mitk::Point2D > quarterCycleUpperLeft;
 
 
   mitk::Point2D curPoint;
   bool curPointIsInside = true;
   curPoint[0] = 0;
   curPoint[1] = radius;
   quarterCycleUpperRight.push_back( upperLeft(curPoint) );
 
   // to estimate if a pixel is inside the circle, we need to compare against the 'outer radius'
   // i.e. the distance from the midpoint [0,0] to the border of the pixel [0,radius]
-  const float outer_radius = static_cast<float>(radius) + 0.5;
+  //const float outer_radius = static_cast<float>(radius) + 0.5;
 
-  while (curPoint[1] >= 0)
+  while (curPoint[1] > 0)
   {
      // Move right until pixel is outside circle
+     float curPointX_squared = 0.0f;
+     float curPointY_squared = (curPoint[1] - centerCorrection[1] ) * (curPoint[1] - centerCorrection[1] );
      while( curPointIsInside )
      {
         // increment posX and chec
         curPoint[0]++;
-        float len = sqrt(curPoint[0] * curPoint[0] + curPoint[1] * curPoint[1]);
-        if ( len > outer_radius )
+        curPointX_squared = (curPoint[0] - centerCorrection[0] ) * (curPoint[0] - centerCorrection[0] );
+        const float len = sqrt( curPointX_squared + curPointY_squared);
+        if ( len > fradius )
         {
            // found first Pixel in this horizontal line, that is outside the circle
            curPointIsInside = false;
         }
      }
      quarterCycleUpperRight.push_back( upperLeft(curPoint) );
 
      // Move down until pixel is inside circle
      while( !curPointIsInside )
      {
         // increment posX and chec
         curPoint[1]--;
-        float len = sqrt(curPoint[0] * curPoint[0] + curPoint[1] * curPoint[1]);
-        if ( len <= outer_radius )
+        curPointY_squared = (curPoint[1] - centerCorrection[1] ) * (curPoint[1] - centerCorrection[1] );
+        const float len = sqrt( curPointX_squared + curPointY_squared);
+        if ( len <= fradius )
         {
            // found first Pixel in this horizontal line, that is outside the circle
            curPointIsInside = true;
            quarterCycleUpperRight.push_back( upperLeft(curPoint) );
         }
 
         // Quarter cycle is full, when curPoint y position is 0
         if (curPoint[1] <= 0)
            break;
      }
 
    }
 
   // QuarterCycle is full! Now copy quarter cycle to other quarters.
   std::vector< mitk::Point2D >::const_iterator it = quarterCycleUpperRight.begin();
   while( it != quarterCycleUpperRight.end() )
   {
      mitk::Point2D p;
      p = *it;
 
      // the contour points in the lower right corner have same position but with negative y values
      p[1] *= -1;
      quarterCycleLowerRight.push_back(p);
 
      // the contour points in the lower left corner have same position
      // but with both x,y negative
      p[0] *= -1;
      quarterCycleLowerLeft.push_back(p);
 
      // the contour points in the upper left corner have same position
      // but with x negative
      p[1] *= -1;
      quarterCycleUpperLeft.push_back(p);
 
      it++;
   }
 
   // fill contour with poins in right ordering, starting with the upperRight block
   mitk::Point3D tempPoint;
   for (int i=0; i<quarterCycleUpperRight.size(); i++)
   {
      tempPoint[0] = quarterCycleUpperRight[i][0];
      tempPoint[1] = quarterCycleUpperRight[i][1];
      tempPoint[2] = 0;
      contourInImageIndexCoordinates->AddVertex( tempPoint  );
   }
   // the lower right has to be parsed in reverse order
   for (int i=quarterCycleLowerRight.size()-1; i>=0; i--)
   {
      tempPoint[0] = quarterCycleLowerRight[i][0];
      tempPoint[1] = quarterCycleLowerRight[i][1];
      tempPoint[2] = 0;
      contourInImageIndexCoordinates->AddVertex( tempPoint);
   }
   for (int i=0; i<quarterCycleLowerLeft.size(); i++)
   {
      tempPoint[0] = quarterCycleLowerLeft[i][0];
      tempPoint[1] = quarterCycleLowerLeft[i][1];
      tempPoint[2] = 0;
      contourInImageIndexCoordinates->AddVertex( tempPoint );
   }
   // the upper left also has to be parsed in reverse order
   for (int i=quarterCycleUpperLeft.size()-1; i>=0; i--)
   {
      tempPoint[0] = quarterCycleUpperLeft[i][0];
      tempPoint[1] = quarterCycleUpperLeft[i][1];
      tempPoint[2] = 0;
      contourInImageIndexCoordinates->AddVertex( tempPoint );
   }
 
   m_MasterContour = contourInImageIndexCoordinates;
 
 }
 
 
 /**
   Just show the contour, get one point as the central point and add surrounding points to the contour.
   */
 bool mitk::PaintbrushTool::OnMousePressed (Action* action, const StateEvent* stateEvent)
 {
   const PositionEvent* positionEvent = dynamic_cast<const PositionEvent*>(stateEvent->GetEvent());
   if (!positionEvent) return false;
 
   m_LastEventSender = positionEvent->GetSender();
   m_LastEventSlice = m_LastEventSender->GetSlice();
 
   return this->OnMouseMoved(action, stateEvent);
 }
 
 
 /**
   Insert the point to the feedback contour,finish to build the contour and at the same time the painting function
   */
 bool mitk::PaintbrushTool::OnMouseMoved   (Action* itkNotUsed(action), const StateEvent* stateEvent)
 {
   const PositionEvent* positionEvent = dynamic_cast<const PositionEvent*>(stateEvent->GetEvent());
 
   CheckIfCurrentSliceHasChanged(positionEvent);
 
   if ( m_LastContourSize != m_Size )
   {
     UpdateContour( stateEvent );
     m_LastContourSize = m_Size;
   }
 
   bool leftMouseButtonPressed(
     stateEvent->GetId() == 530
     || stateEvent->GetId() == 534
     || stateEvent->GetId() == 1
     || stateEvent->GetId() == 5
     );
 
   Point3D worldCoordinates = positionEvent->GetWorldPosition();
   Point3D indexCoordinates;
 
   m_WorkingSlice->GetGeometry()->WorldToIndex( worldCoordinates, indexCoordinates );
 
   MITK_DEBUG << "Mouse at W " << worldCoordinates << std::endl;
   MITK_DEBUG << "Mouse at I " << indexCoordinates << std::endl;
 
   // round to nearest voxel center (abort if this hasn't changed)
   if ( m_Size % 2 == 0 ) // even
   {
     indexCoordinates[0] = ROUND( indexCoordinates[0] /*+ 0.5*/) + 0.5;
     indexCoordinates[1] = ROUND( indexCoordinates[1] /*+ 0.5*/ ) + 0.5;
   }
   else // odd
   {
     indexCoordinates[0] = ROUND( indexCoordinates[0]  ) ;
     indexCoordinates[1] = ROUND( indexCoordinates[1] ) ;
   }
 
   static Point3D lastPos; // uninitialized: if somebody finds out how this can be initialized in a one-liner, tell me
   if ( fabs(indexCoordinates[0] - lastPos[0]) > mitk::eps ||
        fabs(indexCoordinates[1] - lastPos[1]) > mitk::eps ||
        fabs(indexCoordinates[2] - lastPos[2]) > mitk::eps ||
        leftMouseButtonPressed
      )
   {
     lastPos = indexCoordinates;
   }
   else
   {
     MITK_DEBUG << "." << std::flush;
     return false;
   }
 
   MITK_DEBUG << "Mouse at C " << indexCoordinates;
 
   Contour::Pointer contour = Contour::New();
   contour->Initialize();
 
   for (unsigned int index = 0; index < m_MasterContour->GetNumberOfPoints(); ++index)
   {
     Point3D point = m_MasterContour->GetPoints()->ElementAt(index);
     point[0] += indexCoordinates[ 0 ];
     point[1] += indexCoordinates[ 1 ];
 
     contour->AddVertex( point );
   }
 
 
   if (leftMouseButtonPressed)
   {
     FeedbackContourTool::FillContourInSlice( contour, m_WorkingSlice, m_PaintingPixelValue );
     m_WorkingNode->SetData(m_WorkingSlice);
     m_WorkingNode->Modified();
   }
 
   // visualize contour
   Contour::Pointer displayContour = Contour::New();
   displayContour->Initialize();
 
   //for (unsigned int index = 0; index < contour->GetNumberOfPoints(); ++index)
   //{
   //  Point3D point = contour->GetPoints()->ElementAt(index);
   //  if ( m_Size % 2 == 0 ) // even
   //  {
   //    point[0] += 0.5;
   //    point[1] += 0.5;
   //  }
   //  displayContour->AddVertex( point );
   //}
 
   displayContour = FeedbackContourTool::BackProjectContourFrom2DSlice( m_WorkingSlice->GetGeometry(), /*displayContour*/contour );
   SetFeedbackContour( *displayContour );
 
   assert( positionEvent->GetSender()->GetRenderWindow() );
 
   RenderingManager::GetInstance()->RequestUpdate( positionEvent->GetSender()->GetRenderWindow() );
 
   return true;
 }
 
 
 bool mitk::PaintbrushTool::OnMouseReleased(Action* /*action*/, const StateEvent* stateEvent)
 {
     //When mouse is released write segmentationresult back into image
     const PositionEvent* positionEvent = dynamic_cast<const PositionEvent*>(stateEvent->GetEvent());
     if (!positionEvent) return false;
     this->WriteBackSegmentationResult(positionEvent, m_WorkingSlice->Clone());
 
   return true;
 }
 
 /**
   Called when the CTRL key is pressed. Will change the painting pixel value from 0 to 1 or from 1 to 0.
   */
 bool mitk::PaintbrushTool::OnInvertLogic(Action* itkNotUsed(action), const StateEvent* stateEvent)
 {
     // Inversion only for 0 and 1 as painting values
     if (m_PaintingPixelValue == 1)
     {
       m_PaintingPixelValue = 0;
       FeedbackContourTool::SetFeedbackContourColor( 1.0, 0.0, 0.0 );
     }
     else if (m_PaintingPixelValue == 0)
     {
       m_PaintingPixelValue = 1;
       FeedbackContourTool::SetFeedbackContourColorDefault();
     }
     mitk::RenderingManager::GetInstance()->RequestUpdateAll();
     return true;
 }
 
 void mitk::PaintbrushTool::CheckIfCurrentSliceHasChanged(const PositionEvent *event)
 {
     const PlaneGeometry* planeGeometry( dynamic_cast<const PlaneGeometry*> (event->GetSender()->GetCurrentWorldGeometry2D() ) );
     DataNode* workingNode( m_ToolManager->GetWorkingData(0) );
 
     if (!workingNode)
         return;
 
     Image::Pointer image = dynamic_cast<Image*>(workingNode->GetData());
 
     if ( !image || !planeGeometry )
         return;
 
     if(m_CurrentPlane.IsNull())
     {
         m_CurrentPlane = const_cast<PlaneGeometry*>(planeGeometry);
         m_WorkingSlice = SegTool2D::GetAffectedImageSliceAs2DImage(event, image)->Clone();
         m_WorkingNode->ReplaceProperty( "color", workingNode->GetProperty("color") );
         m_WorkingNode->SetData(m_WorkingSlice);
     }
     else
     {
         bool isSameSlice (false);
         isSameSlice = mitk::MatrixEqualElementWise(planeGeometry->GetIndexToWorldTransform()->GetMatrix(),m_CurrentPlane->GetIndexToWorldTransform()->GetMatrix());
         isSameSlice = mitk::Equal(planeGeometry->GetIndexToWorldTransform()->GetOffset(),m_CurrentPlane->GetIndexToWorldTransform()->GetOffset());
         if (!isSameSlice)
         {
             m_ToolManager->GetDataStorage()->Remove(m_WorkingNode);
             m_CurrentPlane = NULL;
             m_WorkingSlice = NULL;
             m_WorkingNode = NULL;
             m_CurrentPlane = const_cast<PlaneGeometry*>(planeGeometry);
             m_WorkingSlice = SegTool2D::GetAffectedImageSliceAs2DImage(event, image)->Clone();
 
             m_WorkingNode = mitk::DataNode::New();
             m_WorkingNode->SetProperty( "levelwindow", mitk::LevelWindowProperty::New( mitk::LevelWindow(0, 1) ) );
             m_WorkingNode->SetProperty( "binary", mitk::BoolProperty::New(true) );
 
             m_WorkingNode->SetData(m_WorkingSlice);
 
             //So that the paintbrush contour vanished in the previous render window
             RenderingManager::GetInstance()->RequestUpdateAll();
         }
 
     }
 
     if(!m_ToolManager->GetDataStorage()->Exists(m_WorkingNode))
     {
 
         m_WorkingNode->SetProperty( "outline binary", mitk::BoolProperty::New(true) );
         m_WorkingNode->SetProperty( "color", workingNode->GetProperty("color") );
         m_WorkingNode->SetProperty( "name", mitk::StringProperty::New("Paintbrush_Node") );
         m_WorkingNode->SetProperty( "helper object", mitk::BoolProperty::New(true) );
         m_WorkingNode->SetProperty( "opacity", mitk::FloatProperty::New(0.8) );
         m_WorkingNode->SetProperty( "includeInBoundingBox", mitk::BoolProperty::New(false));
         m_WorkingNode->SetVisibility(false, mitk::BaseRenderer::GetInstance( mitk::BaseRenderer::GetRenderWindowByName("stdmulti.widget4")));
 
         m_ToolManager->GetDataStorage()->Add(m_WorkingNode);
     }
 }