Blender Master Class

Transmission and Refraction

In addition to reflecting light, surfaces like water or glass also transmit light (allow light to pass through them). In the real world, a part of the incident light (light hitting the surface) is usually reflected, and the rest is transmitted and bent slightly (refracted). The light is bent because as it enters a different medium, its speed changes. This bending of light results in a distorted image when you look through a transparent material. The amount of distortion depends on the object’s index of refraction (IOR), which determines how much the direction of a ray of light is altered at the boundary of the object (see Figure 12-8), and the shape and thickness of the object. For some objects, this effect is significant—for ...