Rendering in Unity is done with Materials and Shaders.
There is a close relationship between Materials and Shaders in Unity.
Materials are definitions of how a surface should be rendered, including references to textures used, tiling information, colour tints and more. The available options for a material depend on which shader the material is using.
Shaders are small scripts that contain the mathematical calculations and algorithms for calculating the colour of each pixel rendered, based on the lighting input and the Material configuration.
A material specifies one specific shader to use, and the shader used determines which options are available in the material.
For most normal rendering - by which we mean characters, scenery, environments, solid and transparent objects, hard and soft surfaces etc., the Standard Shader is usually the best choice. This is a highly customisable shader which is capable of rendering many types of surface in a highly realistic way.
There are other situations where a different built-in shader, or even a custom written shader might be appropriate - such as liquids, foliage, refractive glass, particle effects, cartoony, illustrative or other artistic effects, or other special effects like night vision, heat vision or x-ray vision, etc.
The following pages describe: