I am trying to build opencv 4.5.2 with vtk. I have vtk-8.2.0 installed in /home/user_name/vtk and set

-DVTK_DIR=/home/user_name/vtk/lib/cmake/vtk-8.2, which is the directory that contains VTKConfig.cmake

But cmake is still complaining VTK_DIR not found. Tried with vtk's build directory still won't work (why would normal people keep the huge build directory around after install anyway?)

OS Ubuntu 20.04.

Edited: same issue with opencv master.