Can you tell me How Autocad 2016 is different from its previous versions (specifically Rendering)?

First, in AutoCAD 2016 it uses new rendering engine: Rapid RT. This new engine is physical based lighting rendering. Let’s not cover how it works in details. What we want to emphasize is: it can produce good result in a short time. The settings are simplified; every beginners in rendering can create great result after learning in few minutes.

Shafqat Ali..

Good one bro... :)

Starting with AutoCAD 2016-based products, a new render engine was introduced as a replacement for the "legacy" renderer available in AutoCAD 2015-based products and earlier. This change affects the way 3D models created in AutoCAD 2015-based products and earlier are rendered to an image. You might need to make changes to the lighting, materials, and render settings of your 3D models to generate rendered images of the desired quality and appearance.