Rendering Layered Materials with Diffuse Interfaces

TL;DR

This paper presents a real-time rendering method for layered materials with diffuse interfaces, accurately modeling the appearance of rough dielectric coatings using microfacet lobes and dimension reduction techniques.

Contribution

It introduces a novel approach to efficiently render layered Lambertian surfaces with diffuse interfaces, improving existing layered material models with a new microfacet-based method.

Findings

Accurately renders rough plastics and ceramics in real-time.

Uses microfacet lobes based on first-order directional statistics.

Enhances layered material models to include Lambertian interfaces.

Abstract

In this work, we introduce a novel method to render, in real-time, Lambertian surfaces with a rough dieletric coating. We show that the appearance of such configurations is faithfully represented with two microfacet lobes accounting for direct and indirect interactions respectively. We numerically fit these lobes based on the first order directional statistics (energy, mean and variance) of light transport using 5D tables and narrow them down to 2D + 1D with analytical forms and dimension reduction. We demonstrate the quality of our method by efficiently rendering rough plastics and ceramics, closely matching ground truth. In addition, we improve a state-of-the-art layered material model to include Lambertian interfaces.