VRay Render Settings in Pictures
Rendering is the process of the render engine taking the inputs (meshes, textures, rigs and animations), calculating their combinations and lighting inputs, and displaying the resulting images (or series of images or simulations). For the purposes of games rendering, make sure to read the following resources closely. You will not find better explanations (at the time of this writing).
Unreal Engine 4 Rendering Overview For Artists
Physically Based Rendering: From Theory to Implementation
Common render engines include:
Non-Games
Games
Cry Engine
Frostbite
Lumberyard
Unreal Engine
Unity