MaterialX: metal edge tint should not be multiplied by specular_weight#240
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jstone-lucasfilm merged 4 commits intoAcademySoftwareFoundation:dev_1.2from Jun 5, 2025
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This looks good to me, thanks @portsmouth!
Just to double-check, do we want to include this in dev_1.2 or in dev_1.1.1?
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It seems harmless to include it in |
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For now, let's merge this to its targeted 1.2 branch, and we can integrate it back to 1.1.1 if needed. |
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This changelist removes `specular_weight` from the computation of metal edge tint in OpenPBR Surface, aligning the behavior of this shading model with a [proposed fix](AcademySoftwareFoundation/OpenPBR#240) for OpenPBR 1.2. As described in the proposed fix, the edge-tint color for the `generalized_schlick_bsdf` should not be multiplied by `specular_weight`, as the whole lobe is multiplied by `specular_weight` as well.
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Two bug fixes for the 1.1.1 point release: - Metal edge tint incorrectly multiplied by specular_weight (cherry-picked from #240): the color82 (edge tint) input on metal_bsdf and metal_bsdf_tf was routed through a multiply node that applied specular_weight. Since the whole lobe is already weighted by specular_weight, the edge tint was being double-weighted. Now connects directly to the specular_color interface input. - Connect geometry_thin_walled flag to <surface> (borrowed from AcademySoftwareFoundation/MaterialX#2759): the thin-walled geometry flag was not being passed through to the surface node in the MaterialX graph.
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This changelist removes `specular_weight` from the computation of metal edge tint in OpenPBR Surface, aligning the behavior of this shading model with a [proposed fix](AcademySoftwareFoundation/OpenPBR#240) for OpenPBR 1.2. As described in the proposed fix, the edge-tint color for the `generalized_schlick_bsdf` should not be multiplied by `specular_weight`, as the whole lobe is multiplied by `specular_weight` as well.
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Fixes a bug in the MtlX graph. The edge-tint color for the
generalized_schlick_bsdfshould not be multiplied byspecular_weight, as the whole lobe is multiplied byspecular_weightas well.(Note that MtlX still does the wrong thing if
specular_weight> 1, but that's not fixable on the OpenPBR side, unless we just clamp the weight sospecular_weight> 1 does nothing to the metal).