We need to know some concepts in the 3D Animation industry, these three are concepts used throughout the making of a movie.
Previs – is the process of visualizing a scene before it is physically made, to help fix some problems and have an idea of what everything is going to look like.
Techvis – is the process of mapping everything such as cameras, actors positions, lights, camera cranes, etc to help create the final footage. This process is like a technical sheet of the previs.
Postvis – is the process of visualizing a rough idea of the final result of a movie before going in to post-production, so not long after the footage is shot the directors have the ability to see what it is going to look like with some vfx and animation.