Bella

Bella is a spectral render engine which models the complexities of optical physics in ways that are as correct as possible, using analogies grounded in the real world, to produce a system that behaves in a predictable and intuitive way.

Simplicity is a key focus of Bella. The Bella solvers avoid obscure non-physical parameters, such that there is very little to learn, and very little trial and error involved in rendering any particular scene.