OpenPBR Change Log

This file gives a high level overview of the changes introduced between versions, relative to version 1.0.

How to read this document : ✨ new feature | 🎨 look-changing | 🐛 bug fix

[1.1.1] - April 17, 2026

🐛 Implementation flexibility #248: Adds a new section to the specification formally stating that implementers of the specification are free to use approximations, for example for low-power constraints.
🐛 Thin-walled subsurface #258: Clarifies the interaction of geometry_thin_walled and subsurface and how it affects subsurface_radius and subsurface_scale.
🐛 HDR emission color #260: Allows values above 1 for emission_color.
🐛 More examples #257: Adds more material examples.
🐛 MaterialX hints #265: Adds MaterialX code generation hints.
🐛 Metal edge tint and ignored thin-walled #300: Fixes two issues in the MaterialX implementation, the edge tint was incorrectly multiplied by the specular weight (backported from #240) and geometry_thin_walled was not connected to the shader (backported from AcademySoftwareFoundation/MaterialX#2759).
🐛 New logo #235: Uses the new logo in the specification.
🐛 Broken links #230: Fixes broken links in the specification.
🐛 Improved wording #218: Adds various clarifications and rewordings to the specification.
🐛 Added Changelog #289: Adds a changelog to the project.
🐛 New images #236: Updates images for the model schematic illustration, glossy diffuse wood, fuzz roughness and new images for anisotropy.
🐛 Revised thin-film section #262: Expands the thin-film specification and revises it to make it clearer.

✨ Enable Zeltner sheen #217: This change enables Zeltner sheen in the reference implementation of OpenPBR, leveraging the new functionality in MaterialX.
🎨 Change thin film IOR default #211: This won't make much difference to the look in implementations that ignore the adjacent IORs of the film, but for those that take it into account, this will make the film visible rather than invisible by default (since specular_ior is 1.5 by default, and coat_ior 1.6).
🎨 Update subsurface color types #220: Changes subsurface_radius_scale from vector3 to color3, aligning the type with its per-channel usage.
🐛 Updated OpenPBR default example #216: Updates the OpenPBR default example, matching its values to the latest default values of the shading model.
🐛 Allow darkening in fuzz #207: Allows fuzz to darken as well as lighten the reflection.
🐛 Resource section #215: Adds a resource section to the front page of the project.
🐛 Clearer emission color formula #209: Clarifies the formula for the emission color.
🐛 Version update #221: Updates the specification and MaterialX node definition to 1.1.