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Google Filament Documentation

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Google (Filament team)

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Description

(Filament.md.html) is the primary theory reference for Google's Filament physically based renderer. Hosted on GitHub Pages, it explains the equations and design choices behind Filament's material and lighting models for contributors and engine programmers.

The document walks through PBR principles, notation, and a standard microfacet BRDF with GGX normal distribution, Smith geometry term, and Fresnel handling, plus energy conservation and multiscattering compensation. Extended sections cover clear coat, anisotropy, subsurface approximation, cloth and velvet models, parameter remapping, and mobile half-float precision limits.

Filament targets real-time performance on mobile OpenGL ES class GPUs while staying interoperable with common DCC PBR workflows. Companion docs cover Materials.md for authoring and integration topics; this file focuses on why specific BRDF forms were chosen.

Content is free online under Filament's open-source repository. Code snippets map theory to the engine implementation without replacing hands-on API tutorials.

Standard reference for developers using or extending Filament on Android and other platforms; cited in Google's performance case studies and community discussions of mobile PBR implementation details.