In trying to track down some segfaults in ITK's VtkGlue code, I discovered that INCLUDE(${VTK_USE_FILE}) is required after find_package(VTK REQUIRED) Without INCLUDE(${VTK_USE_FILE}), vtkRenderWindow::New() returns NULL; Apparently, in the past, the INCLUDE(${VTK_USE_FILE}) must have been optional. Is this correct? Bill