"Shrek 2" made two technological breakthroughs in the production process: light bounce shader (similar to global light illumination) and subsurface scattering technology. In "Shrek 2", 80% of the lenses used global light illumination technology.
The "light bounce shader" was developed by DreamWorks, whose function is to make light bounce naturally from one surface to another. For example, there is only one small lamp in a dark room, but the light it emits illuminates a large area. This is because the light has been reflected many times in the room. In the same way, the light bounce shader can also calculate where the light from a lamp bounces.
The subsurface scattering plays a role of "combining inside and outside". Many people may not realize that light can penetrate under our skin, but those who have played "flashlight on the palm" should know that the light passes through the palm, and the hand looks almost transparent. Subsurface scattering is a technology developed to imitate translucent skin.
