In this video http://youtu.be/8SxTqlom3Fg?t=18m16s at around 18 mins in, the author explains that he uses shaders, world textures, which basically float on top, and shows how other meshes (rocks) dynamically update depending on their rotation.
I guess this doc is relevant WorldPositionOffset | Unreal Engine Documentation
However, maybe someone could clarify and briefly outline the required steps and or point to a tutorial? Thanks.