Lighting and rendering are central components of every realistic scene and space in visual effects (or VFX). It can make or break your render. In the graphic industry, a polygonal model or external visual elements are crafted into one same image through careful manipulation and testing, using cutting edge technologies and producing a controlled photorealistic environment. 

Rendering, have to know how to previously set up your scene. Getting good renders is a very precise process that requires previously having all passes together. It is a time consuming process.