Physically based rendering is a well-known concept these days and is the basis for photo-realistic rendering. The basic idea is to follow the physics of light and how it interacts with materials in real-world, in the rendering pipeline.

I developed a physically based deferred rendering and lighting solution for Unity featuring:

• Used sub-sampling for G-Buffer to pack more material properties, and illumination
  buffer to support colored specular reflections
• Indirect illumination solution based on a mix of parallax corrected reflection probes, screen-space directional occlusion and reflections, and object-space PRT

Below is some of  the reference material tests that was done for both shading quality test and artists’ training.

Brushed Iron

Iron

Brushed Cobalt

Brushed Titanium

Titanium

Brushed Silver

Silver

Brushed Nickel

Nickel

Brushed Gold

Gold

Brushed Copper

Copper

Cobalt

Brushed Aluminium

Aluminium