How to make Z axis parallel to a random vector - Kinematics

Pose rotation is given by rotation vector [rx, ry, rz].

They can be obtained by calculating rotation matrix.
I studied from here and read “Rotation vector”(page 17) of “Robotics in UR Robots_March 2019.pdf”.

https://forum.universal-robots.com/t/robot-theory-and-how-to-use-it-in-ur-robots/3863