Version 1.1.1

Added

• 🐛 New logo #235: Uses the new logo in the specification.
• 🐛 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.
• 🐛 More examples #257: Adds more material examples.
• 🐛 MaterialX hints #265: Adds MaterialX code generation hints.
• 🐛 Added Changelog #289: Adds a changelog to the project.

Changed

• 🐛 Improved wording #218: Adds various clarifications and rewordings to the specification.
• 🐛 New images #236: Updates images for the model schematic illustration, glossy diffuse wood, fuzz roughness and new images for anisotropy.
• 🐛 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.
• 🐛 Revised thin-film section #262: Expands the thin-film specification and revises it to make it clearer.

Fixed

• 🐛 Broken links #230: Fixes broken links in the specification.
• 🐛 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).

Version 1.1

Added

• Update OpenPBR default example by @jstone-lucasfilm in #216
• Add note about dark fuzz by @portsmouth in #207
• Add a "resources" section to the front page by @portsmouth in #215

Changed

• Enable Zeltner sheen by @jstone-lucasfilm in #217
• Clarify formula for emission color by @portsmouth in #209
• Update specification and reference to v1.1 by @jstone-lucasfilm in #221

Fixed

• Change thin film IOR default by @portsmouth in #211
• Update subsurface color types by @jstone-lucasfilm in #220

Version 1.0

Added

• Update acknowledgement list by @virtualzavie in #198
• Add coat_darkening to default example by @jstone-lucasfilm in #199
• Add uiname field to .mtlx nodedef by @portsmouth in #204

Changed

• Enable diffuse energy compensation by @jstone-lucasfilm in #201
• Diffuse base_weight description changed to match MaterialX EON implementation by @portsmouth in #205
• Update BibTeX citation (date, and capitalization) by @portsmouth in #213
• Update specification and reference to v1.0 by @jstone-lucasfilm in #214

Fixed

• Fix default value of transmission_dispersion_abbe_number in .mtlx by @portsmouth in #206
• Implement TIR fix in MaterialX by @portsmouth in #203

Version 0.5

Release Candidate for OpenPBR v1.0

Added

• Add coat darkening and saturation effects by @portsmouth in #162
• Define Oren-Nayar lobe explicitly as EON model (i.e. energy-compensated Fujii) by @portsmouth in #174
• Specify the anisotropy direction by @virtualzavie in #170
• Coat roughening convolution formula by @portsmouth in #172
• Add a discussion/solution of the coat "spurious TIR" issue by @portsmouth in #166
• Add white furnace testing section by @portsmouth in #192

Changed

• Thin-film improvements by @portsmouth in #167
• Remove Future work notes and left over comments by @virtualzavie in #181
• Rework readme links by @virtualzavie in #182
• Remove conclusion section by @portsmouth in #186
• Upgrade reference implementation to 1.39 by @jstone-lucasfilm in #188
• Layer diagram improvements by @portsmouth in #189
• Update the coat_darkening parameter to default to 1 by @portsmouth in #193
• Initial cleanup for 1.0. by @portsmouth in #191
• Slightly shift TOC closer to teaser image. by @portsmouth in #194
• Update contributors list. by @portsmouth in #195
• Update specification and reference to v0.5 by @jstone-lucasfilm in #196

Fixed

• Fix uifolder name for subsurface weight by @fpliu in #184
• Fix IOR schematic figure in thin-film section by @portsmouth in #185

New Contributors

• @fpliu made their first contribution in #184

Full Changelog: v0.4...v0.5

Version 0.4

Added

• Add volume shading support by @msuzuki-nvidia in #169
• Add a discussion of the difference between entering/exiting light transport by @portsmouth in #168

Changed

• Making roughness ranges all [0,1] by @portsmouth in #160
• Define the glossy-diffuse albedo to explicitly correct for darkening by @portsmouth in #165
• Rename base_roughness to base_diffuse_roughness by @virtualzavie in #175
• Update behavior of specular_weight, specular_ior_level, coat_ior_level by @portsmouth in #157
• Subsurface refactor by @portsmouth in #171
• Align example material names by @jstone-lucasfilm in #177
• Update specification and reference to v0.4 by @jstone-lucasfilm in #178

Fixed

• Remove unused transmission roughness from reference graph by @portsmouth in #173

Version 0.3

Added

• Add example materials by @AntonPalmqvist in #147

Changed

• Remove Standard Surface approximation of coat darkening by @jstone-lucasfilm in #135
• Update anisotropy in reference graph by @jstone-lucasfilm in #156
• Update version and date by @jstone-lucasfilm in #164

Fixed

• Fix front-page link to license file by @jstone-lucasfilm in #133
• Minor typo fixes by @portsmouth in #137
• Fix transmission implementation and improve specification by @portsmouth in #151
• Address parameter updates from #151 by @msuzuki-nvidia in #161

Version 0.2

Initial release of the specification and reference implementation for the OpenPBR Surface shading model.