11. Propagation Models

Propagation models define how rays propagate through a medium. Each Material object has a PropagationModel that determines how the ray’s position changes as it travels.

11.1. BasePropagationModel

The BasePropagationModel is an abstract base class that defines the interface for all propagation models. It has one main method:

• propagate(rays, t): Propagates rays a distance t through the medium.

11.2. Homogeneous

The Homogeneous model is used for materials with a uniform refractive index. It’s the most common propagation model.

11.3. GRIN - gradient-index

The GRIN model is used for gradient-index materials, where the refractive index varies with position.