SpongeCake: A Layered Microflake Surface Appearance Model

A Position‐Free Path Integral for Homogeneous Slabs and Multiple Scattering on Smith Microfacets

“…A first obvious application of our method is for BSDFs that model far-field scattering by slabs of homogeneous media. These slabs could act as a component in specialized BSDFs such as those for paper [PdMJ14], or in more general layered material frameworks either enclosed by dielectric interfaces [GHZ18; WW07] or in a stack of slabs with index-matched interfaces [WJHY21]. In the following, we will focus on the straightforward case of a BSDF representing reflectance from a single, index-matched homogeneous slab.…”

“…Layered slabs Another interesting extension of our work would be to natively handle layered, index-matched slabs, such as those of Wang et al [WJHY21]. Although we can readily support such use cases by layering individual instances of Section 5, further variance reduction may be possible by treating the slabs as a combined medium with strata of different extinction, and tracking a single height distribution over all slabs simultaneously.…”