diff --git a/Modules/IGT/IO/mitkNavigationDataPlayerBase.cpp b/Modules/IGT/IO/mitkNavigationDataPlayerBase.cpp
index 6bea38ce09..b03e87c271 100644
--- a/Modules/IGT/IO/mitkNavigationDataPlayerBase.cpp
+++ b/Modules/IGT/IO/mitkNavigationDataPlayerBase.cpp
@@ -1,108 +1,109 @@
 /*===================================================================
 
 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 "mitkNavigationDataPlayerBase.h"
 
 // include for exceptions
 #include "mitkIGTException.h"
 
 mitk::NavigationDataPlayerBase::NavigationDataPlayerBase()
 {
   m_Name ="Navigation Data Player Source";
 }
 
 mitk::NavigationDataPlayerBase::~NavigationDataPlayerBase()
 {
 }
 
 void mitk::NavigationDataPlayerBase::UpdateOutputInformation()
 {
   this->Modified();  // make sure that we need to be updated
   Superclass::UpdateOutputInformation();
 }
 
 bool mitk::NavigationDataPlayerBase::IsAtEnd()
 {
   return m_NavigationDataSetIterator == m_NavigationDataSet->End();
 }
 
 void mitk::NavigationDataPlayerBase::SetNavigationDataSet(NavigationDataSet::Pointer navigationDataSet)
 {
   m_NavigationDataSet = navigationDataSet;
   m_NavigationDataSetIterator = navigationDataSet->Begin();
 
   this->InitPlayer();
 }
 
 unsigned int mitk::NavigationDataPlayerBase::GetNumberOfSnapshots()
 {
   return m_NavigationDataSet.IsNull() ? 0 : m_NavigationDataSet->Size();
 }
 
 unsigned int mitk::NavigationDataPlayerBase::GetCurrentSnapshotNumber()
 {
   return m_NavigationDataSet.IsNull() ? 0 : m_NavigationDataSetIterator - m_NavigationDataSet->Begin();
 }
 
 void mitk::NavigationDataPlayerBase::InitPlayer()
 {
   if ( m_NavigationDataSet.IsNull() )
   {
     mitkThrowException(mitk::IGTException)
       << "NavigationDataSet has to be set before initializing player.";
   }
 
   if (GetNumberOfOutputs() == 0)
   {
     int requiredOutputs = m_NavigationDataSet->GetNumberOfTools();
     this->SetNumberOfRequiredOutputs(requiredOutputs);
 
     for (unsigned int n = this->GetNumberOfOutputs(); n < requiredOutputs; ++n)
     {
       DataObjectPointer newOutput = this->MakeOutput(n);
       this->SetNthOutput(n, newOutput);
       this->Modified();
     }
   }
   else if (GetNumberOfOutputs() != m_NavigationDataSet->GetNumberOfTools())
   {
     mitkThrowException(mitk::IGTException)
       << "Number of tools cannot be changed in existing player. Please create "
       << "a new player, if the NavigationDataSet has another number of tools now.";
   }
 
   this->Modified();
+  this->GenerateData();
 }
 
 void mitk::NavigationDataPlayerBase::GraftEmptyOutput()
 {
   for (unsigned int index = 0; index < m_NavigationDataSet->GetNumberOfTools(); index++)
   {
     mitk::NavigationData* output = this->GetOutput(index);
     assert(output);
 
     mitk::NavigationData::Pointer nd = mitk::NavigationData::New();
     mitk::NavigationData::PositionType position;
     mitk::NavigationData::OrientationType orientation(0.0,0.0,0.0,0.0);
     position.Fill(0.0);
 
     nd->SetPosition(position);
     nd->SetOrientation(orientation);
     nd->SetDataValid(false);
 
     output->Graft(nd);
   }
 }
\ No newline at end of file
diff --git a/Modules/IGT/IO/mitkNavigationDataPlayerBase.h b/Modules/IGT/IO/mitkNavigationDataPlayerBase.h
index afd127965e..d3a8af503d 100644
--- a/Modules/IGT/IO/mitkNavigationDataPlayerBase.h
+++ b/Modules/IGT/IO/mitkNavigationDataPlayerBase.h
@@ -1,99 +1,100 @@
 /*===================================================================
 
 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.
 
 ===================================================================*/
 
 #ifndef MITKNavigationDataPlayerBase_H_HEADER_INCLUDED_
 #define MITKNavigationDataPlayerBase_H_HEADER_INCLUDED_
 
 #include "mitkNavigationDataSource.h"
 #include "mitkNavigationDataSet.h"
 
 namespace mitk{
   /**Documentation
   * \brief Base class for using mitk::NavigationData as a filter source.
   * Subclasses can play objects of mitk::NavigationDataSet.
   *
   * \ingroup IGT
   */
   class MitkIGT_EXPORT NavigationDataPlayerBase
     : public NavigationDataSource
   {
   public:
     mitkClassMacro(NavigationDataPlayerBase, NavigationDataSource);
 
     /**
     * \brief Used for pipeline update just to tell the pipeline that we always have to update.
     */
     virtual void UpdateOutputInformation();
 
     itkGetMacro(NavigationDataSet, NavigationDataSet::Pointer);
 
     /**
     * \brief Set mitk::NavigationDataSet for playing.
     * Player is initialized by call to mitk::NavigationDataPlayerBase::InitPlayer()
     * inside this method. Method must be called before this object can be used as
     * a filter source.
     *
     * @param navigationDataSet mitk::NavigationDataSet which will be played by this player.
     */
     void SetNavigationDataSet(NavigationDataSet::Pointer navigationDataSet);
 
     /**
     * \brief Getter for the size of the mitk::NavigationDataSet used in this object.
     *
     * @return Returns the number of navigation data snapshots available in the player.
     */
     unsigned int GetNumberOfSnapshots();
 
     unsigned int GetCurrentSnapshotNumber();
 
     /**
     * \brief This method checks if player arrived at end of file.
     *
     * @return true if last mitk::NavigationData object is in the outputs, false otherwise
     */
     bool IsAtEnd();
 
   protected:
     NavigationDataPlayerBase();
     virtual ~NavigationDataPlayerBase();
 
     /**
     * \brief Every subclass hast to implement this method. See ITK filter documentation for details.
     */
     virtual void GenerateData() = 0;
 
     /**
     * \brief Initializes the outputs of this NavigationDataSource.
+    * Aftwer calling this method, the first Navigationdata from the loaded Navigationdataset is loaded into the outputs.
     */
     void InitPlayer();
 
     /**
     * \brief Convenience method for subclasses.
     * When there are no further mitk::NavigationData objects available, this
     * method can be called in the implementation of mitk::NavigationDataPlayerBase::GenerateData().
     */
     void GraftEmptyOutput();
 
     NavigationDataSet::Pointer m_NavigationDataSet;
 
     /**
     * \brief Iterator always points to the NavigationData object which is in the outputs at the moment.
     */
     mitk::NavigationDataSet::NavigationDataSetIterator m_NavigationDataSetIterator;
   };
 } // namespace mitk
 
 #endif /* MITKNavigationDataSequentialPlayer_H_HEADER_INCLUDED_ */