title: CMake: how to set VTK_DIR?
body: <p>This is one part of my <code>CMakeLists.txt</code></p>
  
  <pre><code>set (VTK_DIR "/usr/include/vtk-5.8")
  
  find_package(VTK REQUIRED)
  include(${VTK_USE_FILE})
  IF(VTK_FOUND)
    message("found VTK. Version:" ${VTK_VERSION}. VTK_DIR: ${VTK_DIR})
  ELSE(VTK_FOUND)
    MESSAGE(FATAL_ERROR
      "Cannot build the executable without VTK. Please set the                                                                                                   
  VTK_DIR")
  ENDIF(VTK_FOUND)
  </code></pre>
  
  <p><code>cmake .</code> tells me:</p>
  
  <blockquote>
    <p>found VTK. Version:6.0.0.VTK_DIR:/usr/local/lib/cmake/vtk-6.0</p>
  </blockquote>
  
  <p>Giving the VTK_DIR in the command line does not help either:</p>
  
  <pre><code>cmake -DVTK_DIR:PATH=/usr/include/vtk-5.8 .
  </code></pre>
  
  <p>Still cmake looks in <code>/usr/local/lib/cmake/vtk-6.0</code> for VTK.</p>
  
  <p>What is wrong here?</p>