[CMake] CMake does not find module, though it's in MODULE_PATH

[Florian Lindner]

Hello,

my CMake 3.6.2 complains about not finding FindEigen3.cmake

CMake Error at CMakeLists.txt:62 (find_package):
  By not providing "FindEigen3.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Eigen3", but
  CMake did not find one.

  Could not find a package configuration file provided by "Eigen3" with any
  of the following names:

    Eigen3Config.cmake
    eigen3-config.cmake

  Add the installation prefix of "Eigen3" to CMAKE_PREFIX_PATH or set
  "Eigen3_DIR" to a directory containing one of the above files.  If "Eigen3"
  provides a separate development package or SDK, be sure it has been
  installed.

However, it's clearly there in ls $CMAKE_MODULE_PATH/FindEigen3.cmake

I try to use it like find_package(Eigen3 REQUIRED)

What else could be wrong there?

Thanks!

Florian