title: How to use QVTKWidget
body: <p>I am working at a part of a big project.
  My goal is it to show a <code>vtkRenderer</code> in a <code>QWidget</code>. For that I wrote this class:</p>
  
  <pre><code>CModelViewWidget::CModelViewWidget(QWidget *parent) :
  QWidget(parent)
  {
      _qVtkWidget = new QVTKWidget(this,Qt::Widget);
      _rend = vtkRenderer::New();
  
      this-&gt;showVTK();
  
      _qVtkWidget-&gt;GetRenderWindow()-&gt;AddRenderer(_rend);
  
  }
  </code></pre>
  
  <p>where <code>_qVtkWidget</code> is a <code>QVTKWidget</code>, <code>_rend</code> a <code>vtkRenderer</code> and <code>showVTK()</code> a function that adds a sphere to <code>_rend</code>.</p>
  
  <p>I am able to compile this things, but when I want to test them the program crashes. The error message is:</p>
  
  <pre><code>[pathToProject]/qtCT/qtcreator-build/bin/mabviewer: symbol lookup error:[pathToProject]/qtCT/qtcreator-build/lib/libplugwdgt_modelviz.so: undefined symbol: _ZN10QVTKWidgetC1EP7QWidget6QFlagsIN2Qt10WindowTypeEE
  </code></pre>
  
  <p>I am using VTK5.8, QTCreator 2.4.1 with QT 4.7.4 and cmake. I linked the project and VTK and showing a normal <code>vtkRenderWindow</code> works fine. Is there something else to do, before <code>QVTKWidget</code> works?</p>