bool mitk::PointSetDataInteractor::AddPoint(StateMachineAction* stateMachineAction, InteractionEvent* interactionEvent)
{
  // Find the position, the point is to be added to: first entry with
  // empty index. If the Set is empty, then start with 0. if not empty,
  // then take the first index which is not occupied
  int lastPosition = 0;
  PointSet::PointsContainer* pointsContainer = m_PointSet->GetPointSet(0)->GetPoints();

  if (!pointsContainer->empty())
  {
    mitk::PointSet::PointsIterator it, end;
    it = pointsContainer->Begin();
    end = pointsContainer->End();
    while (it != end)
    {
      if (!pointsContainer->IndexExists(lastPosition))
        break;
      ++it;
      ++lastPosition;
    }
  }

  InteractionPositionEvent* positionEvent = dynamic_cast<InteractionPositionEvent*>(interactionEvent);
  if (positionEvent != NULL)
  {
    IsClosedContour(stateMachineAction, interactionEvent);
    // Get time step from BaseRenderer
    int timeStep = positionEvent->GetSender()->GetTimeStep();
    mitk::Point3D point = positionEvent->GetPositionInWorld();
    m_PointSet->InsertPoint(lastPosition, point, timeStep);
    m_NumberOfPoints++;
    GetDataNode()->SetData(m_PointSet);
    GetDataNode()->Modified();
    if (m_MaxNumberOfPoints != 0 && m_NumberOfPoints >= m_MaxNumberOfPoints)
    {
      InternalEvent::Pointer event = InternalEvent::New(NULL, this, "MaxNumberOfPoints");
      positionEvent->GetSender()->GetDispatcher()->QueueEvent(event.GetPointer());
    }
    mitk::RenderingManager::GetInstance()->RequestUpdateAll();
    return true;
  }
  else
  {
    return false;
  }
}