CMake: how to set VTK_DIR?

Question

This is one part of my CMakeLists.txt

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)

cmake . tells me:

found VTK. Version:6.0.0.VTK_DIR:/usr/local/lib/cmake/vtk-6.0

Giving the VTK_DIR in the command line does not help either:

cmake -DVTK_DIR:PATH=/usr/include/vtk-5.8 .

Still cmake looks in /usr/local/lib/cmake/vtk-6.0 for VTK.

What is wrong here?

Answer 1

VTK_DIR is a cache variable, which keeps its state across CMake invocations. You can set it from the command line, or via one of the CMake GUI interfaces.

Or, if you're certain you want to force it from your CMake file itself, you can use this syntax:

SET(VTK_DIR "/usr/include/vtk-5.8" CACHE PATH "VTK directory override" FORCE)

Answer 2

You should call find_package with the NO_MODULE option,

find_package(VTK REQUIRED NO_MODULE)

This will force CMake to skip the find module, which hasn't been required for a number of releases. You also need to point CMake at the location of the VTKConfig.cmake file, not the C++ headers. Setting CMAKE_PREFIX_PATH to /usr/local would have CMake check /usr/local before any other path for example. If your VTKConfig.cmake is installed in the /usr prefix, then the config file is likely in /usr/lib/cmake/vtk-5.8, and the VTK_DIR should be set to that too.

Answer 3

What you need is VTK install subdirectory with VTKConfig.cmake . Alternatively, build directory might work as well.

As suggested by Peter, try:

SET(VTK_DIR "/usr/include/vtk-5.8/XXX" CACHE PATH "VTK directory override" FORCE)

and point it to the folder where you have VTKConfig.cmake .

YOu could install cmake-qt-gui - there you can easily enter the required paths using a GUI. If it doesn't use the path you entered, it means this is not the path it wants (see above).