From a20bef0534e87ce61671940c0e25e1c90318fdad Mon Sep 17 00:00:00 2001
From: Lee Kerley <154285602+ld-kerley@users.noreply.github.com>
Date: Wed, 7 Aug 2024 09:00:00 -0700
Subject: [PATCH 1/4] Fix incorrectly transposed matrix for displayp3
 colorspaces (#1960)

When originally authored the matrix was authored transposed. Further internal testing revealed this to manifest as an undesired shift towards red.
---
 libraries/cmlib/cmlib_ng.mtlx | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libraries/cmlib/cmlib_ng.mtlx b/libraries/cmlib/cmlib_ng.mtlx
index f6f844f48e..4ac94c2f7a 100644
--- a/libraries/cmlib/cmlib_ng.mtlx
+++ b/libraries/cmlib/cmlib_ng.mtlx
@@ -315,7 +315,8 @@
 
   <nodegraph name="NG_srgb_displayp3_to_lin_rec709_color3" nodedef="ND_srgb_displayp3_to_lin_rec709_color3">
     <constant name="mat" type="matrix33">
-      <input name="value" type="matrix33" value="1.22493029, -0.22492968, 0.00000006, -0.04205868,  1.04205894, -0.00000001, -0.01964128, -0.07864794, 1.09828925" />
+      <input name="value" type="matrix33"
+             value="1.22493029, -0.04205868, -0.01964128, -0.22492968, 1.04205894, -0.07864794, 0.00000006,-0.00000001, 1.09828925"/>
     </constant>
     <!--  Use srgb_texture_to_lin_rec709 to convert from sRGB to Lin before passing to the mat conversion -->
     <srgb_texture_to_lin_rec709 name="srgb_transform" type="color3">
@@ -354,7 +355,8 @@
 
   <nodegraph name="NG_lin_displayp3_to_lin_rec709_color3" nodedef="ND_lin_displayp3_to_lin_rec709_color3">
     <constant name="mat" type="matrix33">
-      <input name="value" type="matrix33" value="1.22493029, -0.22492968, 0.00000006, -0.04205868,  1.04205894, -0.00000001, -0.01964128, -0.07864794, 1.09828925" />
+      <input name="value" type="matrix33"
+             value="1.22493029, -0.04205868, -0.01964128, -0.22492968, 1.04205894, -0.07864794, 0.00000006,-0.00000001, 1.09828925"/>
     </constant>
     <convert name="asVec" type="vector3">
       <input name="in" type="color3" interfacename="in" />

From 65dc595340e1595f8ea7d4eaa4bea7d7066299dd Mon Sep 17 00:00:00 2001
From: Jonathan Stone <jstone@lucasfilm.com>
Date: Wed, 7 Aug 2024 09:00:25 -0700
Subject: [PATCH 2/4] Assign PugiXML to External source folder (#1961)

This changelist assigns the PugiXML project to the External source folder, improving clarity in Visual Studio builds.
---
 source/MaterialXFormat/CMakeLists.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/source/MaterialXFormat/CMakeLists.txt b/source/MaterialXFormat/CMakeLists.txt
index 2f65ab09b2..d75bbc537c 100644
--- a/source/MaterialXFormat/CMakeLists.txt
+++ b/source/MaterialXFormat/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_subdirectory(External/PugiXML)
+set_property(TARGET pugixml PROPERTY FOLDER "External")
 
 file(GLOB materialx_source "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp")
 file(GLOB materialx_headers "${CMAKE_CURRENT_SOURCE_DIR}/*.h*")

From 67702daa934d6bb397ec6e540b7dd41bc5c12650 Mon Sep 17 00:00:00 2001
From: Malia Kuo <mkuo@lucasfilm.com>
Date: Wed, 7 Aug 2024 13:05:31 -0700
Subject: [PATCH 3/4] Additional improvements to MaterialX Lama nodes (#1955)

- Updated LamaGeneralizedSchlick implementation (changed the transmission component from a dielectric BSDF to a generalized schlick BSDF, adjusted implementation of reflectionTint)
- Updated LamaSSS and LamaTranslucent (removed LobeName and matte inputs as they are renderer-specific)
- Updated default values and help documentation of MaterialX Lama nodes to be consistent with Renderman Lama nodes.
---
 libraries/bxdf/lama/lama_conductor.mtlx       |  18 ++-
 libraries/bxdf/lama/lama_dielectric.mtlx      |  24 ++--
 libraries/bxdf/lama/lama_emission.mtlx        |   2 +-
 .../bxdf/lama/lama_generalized_schlick.mtlx   | 116 ++++++++----------
 libraries/bxdf/lama/lama_iridescence.mtlx     |  34 ++++-
 libraries/bxdf/lama/lama_sheen.mtlx           |   2 +-
 libraries/bxdf/lama/lama_sss.mtlx             |  26 ++--
 libraries/bxdf/lama/lama_surface.mtlx         |   6 +-
 libraries/bxdf/lama/lama_translucent.mtlx     |   4 -
 .../surfaceshader/lama/lama_conductor.mtlx    |   2 +-
 .../surfaceshader/lama/lama_emission.mtlx     |   2 +-
 .../surfaceshader/lama/lama_iridescence.mtlx  |   1 +
 .../surfaceshader/lama/lama_translucent.mtlx  |   2 -
 13 files changed, 115 insertions(+), 124 deletions(-)

diff --git a/libraries/bxdf/lama/lama_conductor.mtlx b/libraries/bxdf/lama/lama_conductor.mtlx
index 07a7b7fcd6..4b6b80f64a 100644
--- a/libraries/bxdf/lama/lama_conductor.mtlx
+++ b/libraries/bxdf/lama/lama_conductor.mtlx
@@ -3,15 +3,15 @@
   <nodedef name="ND_lama_conductor" node="LamaConductor" nodegroup="pbr" doc="Lama conductor" version="1.0" isdefaultversion="true">
     <input name="tint" type="color3" value="1, 1, 1" uiname="Tint" uifolder="Main"
            doc="Overall color multiplier. It should be used with parcimony, as a non-white value breaks physicality. The prefered way to define the color of a conductor is through the Fresnel attributes right below." />
-    <input name="fresnelMode" type="integer" uniform="true" enum="Scientific,Artistic" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
-           doc="Fresnel mode" />
+    <input name="fresnelMode" type="integer" uniform="true" enum="Artistic,Scientific" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
+           doc="Switches the Fresnel between Artistic and Scientific parameters. The Artistic mode offers reflectivity in the normal direction and reflectivity90 at the grazing angle. The Scientific mode provides an index of refraction for each rgb component. Note that IOR is only used to calculate the reflectivity value used by the Schlick approximation. When reflectivity90 is 1, then both modes achieve identical results, as one can be mapped to the other." />
     <input name="IOR" type="vector3" value="0.180000007153,0.419999986887,1.37000000477" uiname="IOR" uifolder="Main"
            doc="Index of refraction (often denoted by eta), defining the color reflected by the surface in the normal direction." />
     <input name="extinction" type="vector3" value="3.42000007629,2.34999990463,1.76999998093" uiname="Extinction" uifolder="Main"
            doc="Extinction coefficient (often denoted by kappa), influencing how the reflected color curve evolves between its value in the normal direction (or 0 degree), and 1 when reaching 90 degrees. A null value does not deviate the curve at all." />
     <input name="reflectivity" type="color3" value="0.9450, 0.7772, 0.3737" uiname="Reflectivity" uifolder="Main"
            doc="Color reflected by the surface in the normal direction." />
-    <input name="edgeColor" type="color3" value="0.9979, 0.9813, 0.7523" uiname="Edge Color" uifolder="Main"
+    <input name="edgeColor" type="color3" value="0.7137, 0.7373, 0.4550" uiname="Edge Color" uifolder="Main"
            doc="Indicates how the reflected color curve evolves between its value in the normal direction (or 0 degree), and 1 when reaching 90 degrees. Note that this color is unlikely to be reached, and just bends the curve towards it when reaching grazing angles. A null value does not deviate the curve at all." />
     <input name="roughness" type="float" value="0.1" uimin="0.0" uimax="1.0" uiname="Roughness" uifolder="Main"
            doc="Micro-facet distribution roughness." />
@@ -21,7 +21,7 @@
            doc="Defines the amount of anisotropy, changing the co-tangent axis roughness from the original value to 1 (or to 0 with a negative value)." />
     <input name="anisotropyDirection" type="vector3" defaultgeomprop="Tworld" uiname="Direction" uifolder="Anisotropy"
            doc="Overrides the surface tangent as the anisotropy direction." />
-    <input name="anisotropyRotation" type="float" value="0.0" uiname="Rotation" uifolder="Anisotropy"
+    <input name="anisotropyRotation" type="float" value="0.0" uisoftmin="0.0" uisoftmax="1.0"  uiname="Rotation" uifolder="Anisotropy"
            doc="Rotates the anisotropy direction (possibly overriden by the previous attribute) around the normal, from 0 to 360 degrees." />
     <output name="out" type="BSDF" />
   </nodedef>
@@ -40,13 +40,13 @@
       <input name="in" type="vector3" interfacename="extinction" />
     </convert>
     <switch name="eta_switch" type="color3">
-      <input name="in1" type="color3" nodename="convert_ior" />
-      <input name="in2" type="color3" nodename="artistic_ior" output="ior" />
+      <input name="in1" type="color3" nodename="artistic_ior" output="ior" />
+      <input name="in2" type="color3" nodename="convert_ior" />
       <input name="which" type="integer" interfacename="fresnelMode" />
     </switch>
     <switch name="kappa_switch" type="color3">
-      <input name="in1" type="color3" nodename="convert_extinction" />
-      <input name="in2" type="color3" nodename="artistic_ior" output="extinction" />
+      <input name="in1" type="color3" nodename="artistic_ior" output="extinction" />
+      <input name="in2" type="color3" nodename="convert_extinction" />
       <input name="which" type="integer" interfacename="fresnelMode" />
     </switch>
 
@@ -110,8 +110,6 @@
       <input name="distribution" type="string" value="ggx" />
     </conductor_bsdf>
 
-    <!-- Layered BRDF -->
-
     <!-- Tinted BRDF -->
     <multiply name="tinted_bsdf" type="BSDF">
       <input name="in1" type="BSDF" nodename="conductor_bsdf" />
diff --git a/libraries/bxdf/lama/lama_dielectric.mtlx b/libraries/bxdf/lama/lama_dielectric.mtlx
index 5e98670dd7..eb5509033c 100644
--- a/libraries/bxdf/lama/lama_dielectric.mtlx
+++ b/libraries/bxdf/lama/lama_dielectric.mtlx
@@ -5,12 +5,12 @@
            doc="Color multiplier for external reflection. It should be used with parcimony, as a non-white value breaks physicality." />
     <input name="transmissionTint" type="color3" value="1.0, 1.0, 1.0" uiname="Transmission Tint" uifolder="Main"
            doc="Color multiplier for rays going inside the medium (covers external transmission and internal reflection). It should be used with parcimony, as a non-white value breaks physicality. The prefered way to define the color of a dielectric is through the Interior attributes right below." />
-    <input name="fresnelMode" type="integer" uniform="true" enum="Scientific,Artistic" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
-           doc="Fresnel mode" />
+    <input name="fresnelMode" type="integer" uniform="true" enum="Artistic,Scientific" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
+           doc="Switches the Fresnel parameterization between Artistic and Scientific mode. The Artistic mode offers a scalar value defining the reflectivity in the normal direction. The Scientific mode proposes an index of refraction. Both parameterizations can achieve identical results, as one can be mapped to the other." />
     <input name="IOR" type="float" value="1.5" uimin="1.0" uimax="3.0" uiname="IOR" uifolder="Main"
            doc="Index of refraction (often denoted by eta), defining the amount reflected by the surface in the normal direction, and how the rays are bent by refraction." />
-    <input name="reflectivity" type="float" value="0.04" uiname="Reflectivity" uifolder="Main"
-           doc="Reflectivity" />
+    <input name="reflectivity" type="float" value="0.04" uimin="0.0" uimax="1.0" uisoftmin="0.0" uisoftmax="0.25" uiname="Reflectivity" uifolder="Main"
+           doc="Amount reflected by the surface in the normal direction. Also affects how the rays are bent by refraction." />
     <input name="roughness" type="float" value="0.1" uimin="0.0" uimax="1.0" uiname="Roughness" uifolder="Main"
            doc="Micro-facet distribution roughness." />
     <input name="normal" type="vector3" defaultgeomprop="Nworld" uiname="Normal" uifolder="Main"
@@ -19,16 +19,16 @@
            doc="Defines the amount of anisotropy, changing the co-tangent axis roughness from the original value to 1 (or to 0 with a negative value)." />
     <input name="direction" type="vector3" defaultgeomprop="Tworld" uiname="Direction" uifolder="Anisotropy"
            doc="Overrides the surface tangent as the anisotropy direction." />
-    <input name="rotation" type="float" value="0.0" uiname="Rotation" uifolder="Anisotropy"
+    <input name="rotation" type="float" value="0.0" uisoftmin="0.0" uisoftmax="1.0" uiname="Rotation" uifolder="Anisotropy"
            doc="Rotates the anisotropy direction (possibly overriden by the previous attribute) around the normal, from 0 to 360 degrees." />
     <input name="absorptionColor" type="color3" value="1.0, 1.0, 1.0" uiname="Absorption Color" uifolder="Interior"
-           doc="Absorption color" />
-    <input name="absorptionRadius" type="float" value="1.0" uiname="Absorption Radius" uifolder="Interior"
-           doc="Absorption radius" />
+           doc="Interior volume absorption color. It is defined as the negative logarithm of the extinction coefficient, with values between 0 and 1, such that the object itself and its shadows are tinted proportionnally. If set to 1, there is no absorption, and if set to 0, the object will be completely opaque. Note that for single scattering to kick in, the value must be inferior to 1. This value will also act as coating color, when this node is used as the top material in a layer node." />
+    <input name="absorptionRadius" type="float" value="1.0" uimin="0.0" uiname="Absorption Radius" uifolder="Interior"
+           doc="Distance, in world space units, at which the Absorption Color is assumed to be reached. Can be used to control the rate of absorption." />
     <input name="scatterColor" type="color3" value="0.0, 0.0, 0.0" uiname="Scatter Color" uifolder="Interior"
-           doc="Scatter color" />
+           doc="Color (aka scattering albedo) of the medium, defines what proportion of the light hitting volumetric particles is scattered around by the phase function (as opposed to just absorbed), for each color channel. Only takes effect if the corresponding channel has a non-null density, in other words if the Absorption Color value for that channel is inferior to 1." />
     <input name="scatterAnisotropy" type="float" value="0.0" uimin="-1.0" uimax="1.0" uiname="Scatter Anisotropy" uifolder="Interior"
-           doc="Scatter anisotropy" />
+           doc="Anisotropy of the medium's phase function, ranging from full backward scattering at -1 to forward scattering at 1. Only takes effect if the Scatter Color is non-null." />
     <output name="out" type="BSDF" />
   </nodedef>
 
@@ -47,8 +47,8 @@
       <input name="index" type="integer" value="0" />
     </extract>
     <switch name="fresnel_mode_switch" type="float">
-      <input name="in1" type="float" interfacename="IOR" />
-      <input name="in2" type="float" nodename="ior_float" />
+      <input name="in1" type="float" nodename="ior_float" />
+      <input name="in2" type="float" interfacename="IOR" />
       <input name="which" type="integer" interfacename="fresnelMode" />
     </switch>
 
diff --git a/libraries/bxdf/lama/lama_emission.mtlx b/libraries/bxdf/lama/lama_emission.mtlx
index 87da14bd91..3f731442c1 100644
--- a/libraries/bxdf/lama/lama_emission.mtlx
+++ b/libraries/bxdf/lama/lama_emission.mtlx
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <materialx version="1.39" colorspace="acescg">
   <nodedef name="ND_lama_emission" node="LamaEmission" nodegroup="pbr" doc="Lama emission" version="1.0" isdefaultversion="true">
-    <input name="color" type="color3" value="1.0, 1.0, 1.0" uiname="Color" uifolder="Main"
+    <input name="color" type="color3" value="0.0, 0.0, 0.0" uiname="Color" uifolder="Main"
            doc="Color being uniformly emitted in all directions above the surface." />
     <output name="out" type="EDF" />
   </nodedef>
diff --git a/libraries/bxdf/lama/lama_generalized_schlick.mtlx b/libraries/bxdf/lama/lama_generalized_schlick.mtlx
index c8c5f40f5b..fd7c2ade5d 100644
--- a/libraries/bxdf/lama/lama_generalized_schlick.mtlx
+++ b/libraries/bxdf/lama/lama_generalized_schlick.mtlx
@@ -4,47 +4,41 @@
     <input name="reflectionTint" type="color3" value="1.0, 1.0, 1.0" uiname="Reflection Tint" uifolder="Main"
            doc="Color multiplier for external reflection. It should be used with parcimony, as a non-white value breaks physicality." />
     <input name="transmissionTint" type="color3" value="1.0, 1.0, 1.0" uiname="Transmission Tint" uifolder="Main"
-           doc="Color multiplier for rays going inside the medium (covers external transmission and internal reflection). It should be used with parcimony, as a non-white value breaks physicality. The prefered way to define the color of a dielectric is through the Interior attributes right below." />
-    <input name="fresnelMode" type="integer" uniform="true" enum="Scientific,Artistic" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
-           doc="Fresnel mode" />
+           doc="Color multiplier for rays going inside the medium (covers external transmission and internal reflection). It should be used sparingly, as a non-white value breaks physicality. The prefered way to define the color of a dielectric is through the Interior attributes right below." />
+    <input name="fresnelMode" type="integer" uniform="true" enum="Artistic,Scientific" enumvalues="0,1" value="0" uiname="Fresnel Mode" uifolder="Main"
+           doc="Switches the Fresnel between Artistic and Scientific parameters. The Artistic mode offers reflectivity in the normal direction and reflectivity90 at the grazing angle. The Scientific mode provides an index of refraction for each rgb component. Note that IOR is only used to calculate the reflectivity value used by the Schlick approximation. When reflectivity90 is 1, then both modes achieve identical results, as one can be mapped to the other." />
     <input name="IOR" type="vector3" value="1.5,1.5,1.5" uiname="IOR" uifolder="Main"
-           doc="Index of refraction (often denoted by eta), defining the color reflected by the surface in the normal direction." />
+           doc="Index of refraction (often denoted by eta), defining the amount reflected by the surface in the normal direction, and how the rays are bent by refraction. A separate value can be specified for each color channel, if desired." />
     <input name="reflectivity" type="color3" value="0.04, 0.04, 0.04" uiname="Reflectivity" uifolder="Main"
            doc="Color reflected by the surface in the normal direction." />
-    <input name="reflectivity90" type="color3" value="1.0, 1.0, 1.0" uiname="Reflectivity90" uifolder="Main"
+    <input name="reflectivity90" type="color3" value="1.0, 1.0, 1.0" uiname="Reflectivity 90" uifolder="Main"
            doc="Color reflected by the surface at the grazing angle. Should be kept at 1,1,1 for most materials." />
-    <input name="reflectivityProfile" type="float" value="0.2" uiname="ReflectivityProfile" uifolder="Main"
+    <input name="reflectivityProfile" type="float" value="0.2" uimin="0.0" uimax="1.0" uiname="ReflectivityProfile" uifolder="Main"
            doc="The inverse of the exponent to use for Schlick." />
     <input name="roughness" type="float" value="0.1" uimin="0.0" uimax="1.0" uiname="Roughness" uifolder="Main"
            doc="Micro-facet distribution roughness." />
     <input name="normal" type="vector3" defaultgeomprop="Nworld" uiname="Normal" uifolder="Main"
            doc="Shading normal, typically defined by bump or normal mapping. Defaults to the smooth surface normal if not set." />
-    <input name="anisotropy" type="float" value="0.0" uimin="-1.0" uimax="1.0" uiname="Anisotropy" uifolder="Anisotropy"
-           doc="Defines the amount of anisotropy, changing the co-tangent axis roughness from the original value to 1 (or to 0 with a negative value)." />
+    <input name="anisotropy" type="float" value="-1.0" uimin="-1.0" uimax="1.0" uiname="Anisotropy" uifolder="Anisotropy"
+           doc="Defines the roughness in the co-tangent direction, giving anisotropic reflection if the value differs from the roughness parameter value. A negative value (the default) means use the original roughness value, i.e. no anisotropy. " />
     <input name="anisotropyDirection" type="vector3" defaultgeomprop="Tworld" uiname="Direction" uifolder="Anisotropy"
            doc="Overrides the surface tangent as the anisotropy direction." />
-    <input name="anisotropyRotation" type="float" value="0.0" uiname="Rotation" uifolder="Anisotropy"
+    <input name="anisotropyRotation" type="float" value="0.0" uisoftmin="0.0" uisoftmax="1.0" uiname="Rotation" uifolder="Anisotropy"
            doc="Rotates the anisotropy direction (possibly overriden by the previous attribute) around the normal, from 0 to 360 degrees." />
     <input name="absorptionColor" type="color3" value="1.0, 1.0, 1.0" uiname="Absorption Color" uifolder="Interior"
-           doc="Absorption color" />
-    <input name="absorptionRadius" type="float" value="1.0" uiname="Absorption Radius" uifolder="Interior"
-           doc="Absorption radius" />
+           doc="Interior volume absorption color. It is defined as the negative logarithm of the extinction coefficient, with values between 0 and 1, such that the object itself and its shadows are tinted proportionally. If set to 1, there is no absorption, and if set to 0, the object will be completely opaque. Note that for single scattering to kick in, the value must be inferior to 1. This value will also act as coating color, when this node is used as top layer in a stack." />
+    <input name="absorptionRadius" type="float" value="1.0" uimin="0.0" uiname="Absorption Radius" uifolder="Interior"
+           doc="Distance, in world space units, at which the Absorption Color is assumed to be reached. Can be used to control the rate of absorption." />
     <input name="scatterColor" type="color3" value="0.0, 0.0, 0.0" uiname="Scatter Color" uifolder="Interior"
-           doc="Scatter color" />
+           doc="Color (aka scattering albedo) of the medium, defines what proportion of the light hitting volumetric particles is scattered around by the phase function (as opposed to just absorbed), for each color channel. Only takes effect if the corresponding channel has a non-null density, in other words if the Absorption Color value for that channel is inferior to 1." />
     <input name="scatterAnisotropy" type="float" value="0.0" uimin="-1.0" uimax="1.0" uiname="Scatter Anisotropy" uifolder="Interior"
-           doc="Scatter anisotropy" />
+           doc="Anisotropy of the medium's phase function, ranging from full backward scattering at -1 to forward scattering at 1. Only takes effect if the Scatter Color is non-null." />
     <output name="out" type="BSDF" />
   </nodedef>
 
   <nodegraph name="IMPL_lama_generalized_schlick" nodedef="ND_lama_generalized_schlick">
 
-    <!-- Dielectric IOR -->
-    <extract name="ior_float" type="float">
-      <input name="in" type="vector3" interfacename="IOR" />
-      <input name="index" type="integer" value="0" />
-    </extract>
-
-    <!-- Color0 -->
+    <!-- Color0 and Color90 -->
     <convert name="convert_ior" type="color3">
       <input name="in" type="vector3" interfacename="IOR" />
     </convert>
@@ -64,25 +58,19 @@
       <input name="in1" type="color3" nodename="ior_divide" />
       <input name="in2" type="color3" nodename="ior_divide" />
     </multiply>
-    <multiply name="ior_reflection_tint" type="color3">
-      <input name="in1" type="color3" nodename="ior_multiply" />
-      <input name="in2" type="color3" interfacename="reflectionTint" />
-    </multiply>
-    <multiply name="reflectivity_reflection_tint" type="color3">
+    <switch name="fresnel_mode_switch" type="color3">
       <input name="in1" type="color3" interfacename="reflectivity" />
-      <input name="in2" type="color3" interfacename="reflectionTint" />
-    </multiply>
-    <switch name="fresnel_mode_switch_reflection" type="color3">
-      <input name="in1" type="color3" nodename="ior_reflection_tint" />
-      <input name="in2" type="color3" nodename="reflectivity_reflection_tint" />
+      <input name="in2" type="color3" nodename="ior_multiply" />
       <input name="which" type="integer" interfacename="fresnelMode" />
     </switch>
-
-    <!-- Color90 -->
-    <multiply name="reflectivity90_reflection_tint" type="color3">
-      <input name="in1" type="color3" interfacename="reflectivity90" />
-      <input name="in2" type="color3" interfacename="reflectionTint" />
-    </multiply>
+    <subtract name="transmission_color0" type="color3">
+      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
+      <input name="in2" type="color3" nodename="fresnel_mode_switch" />
+    </subtract>
+    <subtract name="transmission_color90" type="color3">
+      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
+      <input name="in2" type="color3" interfacename="reflectivity90" />
+    </subtract>
 
     <!-- Exponent -->
     <divide name="exponent" type="float">
@@ -91,30 +79,15 @@
     </divide>
 
     <!-- Roughness -->
-    <subtract name="roughness_inverse" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="roughness" />
-    </subtract>
-    <ifgreatereq name="delta" type="float">
-      <input name="in1" type="float" nodename="roughness_inverse" />
-      <input name="in2" type="float" interfacename="roughness" />
+    <ifgreater name="anisotropy_switch" type="float">
       <input name="value1" type="float" interfacename="anisotropy" />
-      <input name="value2" type="float" value="0" />
-    </ifgreatereq>
-    <multiply name="roughness_additional" type="float">
+      <input name="value2" type="float" value="0.0" />
       <input name="in1" type="float" interfacename="anisotropy" />
-      <input name="in2" type="float" nodename="delta" />
-    </multiply>
-    <add name="roughness_bitangent" type="float">
-      <input name="in1" type="float" interfacename="roughness" />
-      <input name="in2" type="float" nodename="roughness_additional" />
-    </add>
-    <clamp name="roughness_bitangent_clamped" type="float">
-      <input name="in" type="float" nodename="roughness_bitangent" />
-    </clamp>
+      <input name="in2" type="float" interfacename="roughness" />
+    </ifgreater>
     <combine2 name="roughness_linear" type="vector2">
       <input name="in1" type="float" interfacename="roughness" />
-      <input name="in2" type="float" nodename="roughness_bitangent_clamped" />
+      <input name="in2" type="float" nodename="anisotropy_switch" />
     </combine2>
     <power name="roughness_anisotropic_squared" type="vector2">
       <input name="in1" type="vector2" nodename="roughness_linear" />
@@ -156,27 +129,32 @@
       <input name="anisotropy" type="float" interfacename="scatterAnisotropy" />
     </anisotropic_vdf>
 
-    <!-- BTDF -->
-    <dielectric_bsdf name="transmission_bsdf" type="BSDF">
+    <!-- Transmission -->
+    <generalized_schlick_bsdf name="transmission_bsdf" type="BSDF">
       <input name="weight" type="float" value="1.0" />
-      <input name="tint" type="color3" interfacename="transmissionTint" />
-      <input name="ior" type="float" nodename="ior_float" />
+      <input name="color0" type="color3" nodename="transmission_color0" />
+      <input name="color90" type="color3" nodename="transmission_color90" />
+      <input name="exponent" type="float" nodename="exponent" />
       <input name="roughness" type="vector2" nodename="roughness_anisotropic_squared_clamped" />
       <input name="normal" type="vector3" interfacename="normal" />
       <input name="tangent" type="vector3" nodename="tangent_rotate_normalize" />
       <input name="distribution" type="string" value="ggx" />
       <input name="scatter_mode" type="string" value="T" />
-    </dielectric_bsdf>
-    <layer name="transmission_layer" type="BSDF">
+    </generalized_schlick_bsdf>
+    <layer name="transmission_interior" type="BSDF">
       <input name="top" type="BSDF" nodename="transmission_bsdf" />
       <input name="base" type="VDF" nodename="interior_vdf" />
     </layer>
+    <multiply name="transmission_layer" type="BSDF">
+      <input name="in1" type="BSDF" nodename="transmission_interior" />
+      <input name="in2" type="color3" interfacename="transmissionTint" />
+    </multiply>
 
-    <!-- BRDF -->
+    <!-- Reflection -->
     <generalized_schlick_bsdf name="reflection_generalized_schlick_bsdf" type="BSDF">
       <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" nodename="fresnel_mode_switch_reflection" />
-      <input name="color90" type="color3" nodename="reflectivity90_reflection_tint" />
+      <input name="color0" type="color3" nodename="fresnel_mode_switch" />
+      <input name="color90" type="color3" interfacename="reflectivity90" />
       <input name="exponent" type="float" nodename="exponent" />
       <input name="roughness" type="vector2" nodename="roughness_anisotropic_squared_clamped" />
       <input name="normal" type="vector3" interfacename="normal" />
@@ -184,10 +162,14 @@
       <input name="distribution" type="string" value="ggx" />
       <input name="scatter_mode" type="string" value="R" />
     </generalized_schlick_bsdf>
+    <multiply name="reflection_layer" type="BSDF">
+      <input name="in1" type="BSDF" nodename="reflection_generalized_schlick_bsdf" />
+      <input name="in2" type="color3" interfacename="reflectionTint" />
+    </multiply>
 
     <!-- BSDF -->
     <layer name="generalized_schlick_bsdf" type="BSDF">
-      <input name="top" type="BSDF" nodename="reflection_generalized_schlick_bsdf" />
+      <input name="top" type="BSDF" nodename="reflection_layer" />
       <input name="base" type="BSDF" nodename="transmission_layer" />
     </layer>
 
diff --git a/libraries/bxdf/lama/lama_iridescence.mtlx b/libraries/bxdf/lama/lama_iridescence.mtlx
index 914f70ae1b..aaf3617965 100644
--- a/libraries/bxdf/lama/lama_iridescence.mtlx
+++ b/libraries/bxdf/lama/lama_iridescence.mtlx
@@ -5,13 +5,17 @@
            doc="Micro-facet distribution roughness." />
     <input name="anisotropy" type="float" value="0.0" uimin="-1.0" uimax="1.0" uiname="Anisotropy" uifolder="Anisotropy"
            doc="Defines the amount of anisotropy, changing the co-tangent axis roughness from the original value to 1 (or to 0 with a negative value)." />
-    <input name="relativeFilmThickness" type="float" value="0.5" uimin="0.0" uimax="1.0" uiname="relativeFilmThickness" uifolder="Main"
+    <input name="anisotropyDirection" type="vector3" defaultgeomprop="Tworld" uiname="Direction" uifolder="Anisotropy"
+               doc="Overrides the surface tangent as the anisotropy direction." />
+    <input name="anisotropyRotation" type="float" value="0.0" uisoftmin="0.0" uisoftmax="1.0" uiname="Rotation" uifolder="Anisotropy"
+           doc="Rotates the anisotropy direction (possibly overriden by the previous attribute) around the normal, from 0 to 360 degrees." />
+    <input name="relativeFilmThickness" type="float" value="0.5" uimin="0.0" uimax="1.0" uiname="Relative Thickness" uifolder="Main"
            doc="Relative thin film thickness in the range from 0 to 1 will be scaled to the minimum and maximum thickness, respectively." />
-    <input name="minFilmThickness" type="float" value="400.0" uiname="minFilmThickness" uifolder="Main"
+    <input name="minFilmThickness" type="float" value="400.0" uimin="0.0" uisoftmin="0.0" uisoftmax="1000.0" uiname="Min. Thickness" uifolder="Main"
            doc="Minimum thin film thickness in nanometers, driving the iridescent effect." />
-    <input name="maxFilmThickness" type="float" value="800.0" uiname="maxFilmThickness" uifolder="Main"
+    <input name="maxFilmThickness" type="float" value="800.0" uimin="0.0" uisoftmin="0.0" uisoftmax="1000.0" uiname="Max. Thickness" uifolder="Main"
            doc="Maximum thin film thickness in nanometers, driving the iridescent effect." />
-    <input name="filmIOR" type="float" value="1.3" uiname="filmIOR" uifolder="Main"
+    <input name="filmIOR" type="float" value="1.3" uimin="0.0" uisoftmin="1.0" uisoftmax="3.0" uiname="IOR" uifolder="Main"
            doc="Thin film index of refraction, driving the iridescent effect." />
     <output name="out" type="BSDF" />
   </nodedef>
@@ -53,6 +57,27 @@
       <input name="in2" type="float" value="0.000001" />
     </max>
 
+    <!-- Tangent -->
+    <normal name="tangent_normal" type="vector3">
+      <input name="space" type="string" value="world" />
+    </normal>
+    <multiply name="tangent_rotate_degree" type="float">
+      <input name="in1" type="float" interfacename="anisotropyRotation" />
+      <input name="in2" type="float" value="-360" />
+    </multiply>
+    <subtract name="tangent_rotate_degree_offset" type="float">
+      <input name="in1" type="float" nodename="tangent_rotate_degree" />
+      <input name="in2" type="float" value="0" />
+    </subtract>
+    <rotate3d name="tangent_rotate" type="vector3">
+      <input name="in" type="vector3" interfacename="anisotropyDirection" />
+      <input name="amount" type="float" nodename="tangent_rotate_degree_offset" />
+      <input name="axis" type="vector3" nodename="tangent_normal" /> />
+    </rotate3d>
+    <normalize name="tangent_rotate_normalize" type="vector3">
+      <input name="in" type="vector3" nodename="tangent_rotate" />
+    </normalize>
+
     <!-- Thinfilm Thickness -->
     <mix name="thinfilm_thickness" type="float">
       <input name="fg" type="float" interfacename="maxFilmThickness" />
@@ -66,6 +91,7 @@
       <input name="ior" type="float" value="1.0" />
       <input name="thinfilm_thickness" type="float" nodename="thinfilm_thickness" />
       <input name="thinfilm_ior" type="float" interfacename="filmIOR" />
+      <input name="tangent" type="vector3" nodename="tangent_rotate_normalize" />
       <input name="distribution" type="string" value="ggx" />
       <input name="scatter_mode" type="string" value="RT" />
     </dielectric_bsdf>
diff --git a/libraries/bxdf/lama/lama_sheen.mtlx b/libraries/bxdf/lama/lama_sheen.mtlx
index 76c7b9597d..8accb41837 100644
--- a/libraries/bxdf/lama/lama_sheen.mtlx
+++ b/libraries/bxdf/lama/lama_sheen.mtlx
@@ -4,7 +4,7 @@
     <input name="color" type="color3" value="1, 1, 1" uiname="Color" uifolder="Main"
            doc="Amount of sheen to add, per channel. When this node is used as top material in a stack, the more sheen is added, the less energy will be transmitted to the base material." />
     <input name="roughness" type="float" value="0.1" uimin="0.0" uimax="1.0" uiname="Roughness" uifolder="Main"
-           doc="Roughness of the sheen effect. Very rough sheen can be used to create a rough diffuse look (when combined with a diffuse node by a stack or mix)." />
+           doc="Roughness of the sheen effect. Very rough sheen can be used to create a rough diffuse look (when combined with a diffuse node by a layer or mix)." />
     <input name="normal" type="vector3" defaultgeomprop="Nworld" uiname="Normal" uifolder="Main"
            doc="Shading normal, typically defined by bump or normal mapping. Defaults to the smooth surface normal if not set." />
     <output name="out" type="BSDF" />
diff --git a/libraries/bxdf/lama/lama_sss.mtlx b/libraries/bxdf/lama/lama_sss.mtlx
index ded26871ff..f09d2da51d 100644
--- a/libraries/bxdf/lama/lama_sss.mtlx
+++ b/libraries/bxdf/lama/lama_sss.mtlx
@@ -6,39 +6,29 @@
     <input name="normal" type="vector3" defaultgeomprop="Nworld" uiname="Normal" uifolder="Main"
            doc="Shading normal, typically defined by bump or normal mapping. Defaults to the smooth surface normal if not set." />
     <input name="sssRadius" type="color3" value="0.0, 0.0, 0.0" uiname="Radius" uifolder="SSS"
-           doc="Diffuse Mean Free Path, expressed for each color channel in mm. Indicates on average how much the light travels under the surface before being scattered. The higher the value, the softer the result will be. If null, the computation simplifies to a Lambertian lobe." />
-    <input name="sssScale" type="float" value="1.0" uiname="Scale" uifolder="SSS"
-           doc="Multiplies the radius, to adjust its scale to the scene at hand. If null, the computation simplifies to a Lambertian lobe." />
+           doc="Diffuse Mean Free Path, expressed for each color channel in mm. Indicates on average how much the light travels under the surface before being scattered. The higher the value, the softer the result will be. If zero (black), which is the default value, the computation simplifies to a Lambertian reflection lobe with no subsurface scattering." />
+    <input name="sssScale" type="float" value="1.0" uimin="0.0" uiname="Scale" uifolder="SSS"
+           doc="Multiplies the radius, to adjust its scale to the scene at hand. If zero, the computation simplifies to a Lambertian reflection lobe with no subsurface scattering." />
     <input name="sssMode" type="integer" uniform="true" enum="Path-traced Davis,Path-traced exponential,Diffusion Burley,Diffusion Burley (mean free path)" enumvalues="0,1,2,3" value="0" uiname="Mode" uifolder="Main"
-           doc="Selects what method should be used to compute sub-surface scattering. Proposes two path-traced variants, and a more traditional approximate diffusion model." />
-    <input name="sssIOR" type="float" value="1.0" uimin="1.0" uimax="2.0" uiname="IOR" uifolder="SSS"
+           doc="Selects what method should be used to compute sub-surface scattering. The first two options are path-traced variants, with different attenuation strategies applied to the path. The second two are traditional diffusion models. The first Diffusion Burley expects a diffuse mean free path in mm (the average length of a path measured from its entry and exit points after subsurface scattering interactions). The second Diffusion Burley uses mean free path in mm (the average distance that a photon travels in a subsurface volume, which is 1/sigma_t, where sigma_t is the extinction coefficient)." />
+    <input name="sssIOR" type="float" value="1.0" uimin="1.0" uisoftmin="1.0" uisoftmax="2.0"  uiname="IOR" uifolder="SSS"
            doc="Index of refraction use to trigger cases of total internal reflections, when the paths are reaching the surface after having travelled under it. Can be used to avoid excessive glow in highly curved regions (corners, creases, ...)." />
-    <input name="sssAnisotropy" type="float" value="0.0" uimin="-1.0" uimax="1.0" uiname="Anisotropy" uifolder="SSS"
+    <input name="sssAnisotropy" type="float" value="0.0" uimin="0.0" uimax="1.0" uiname="Anisotropy" uifolder="SSS"
            doc="Higher values makes light scatter predominantly forward under the surface, making the object look less diffuse and more transparent." />
     <input name="sssBleed" type="float" value="0.0" uimin="0.0" uimax="1.0" uiname="Bleed" uifolder="SSS"
            doc="Controls the depth of light bleed in the subsurface medium. Has the effect of increasing the distance light travels in the medium while preserving fine detail, compared to increasing the Mean Free Path." />
     <input name="sssFollowTopology" type="float" value="0.0" uimin="0.0" uimax="1.0" uiname="Follow Topology" uifolder="SSS"
-           doc="Controls how strongly normals are considered in the subsurface computation." />
+           doc="Controls how strongly normals are considered in the subsurface computation. For path-traced sss (sssMode 0 and 1), the followTopology parameter reduces sss paths being blocked by backsides behind a surface, but also reduces sss from one side to another in convex regions such as ridges and ears. For diffusion sss (sssMode 2 and 3), the followTopology parameter reduces sss from one side to another in concave regions such as crevasses and wrinkles." />
     <input name="sssSubset" type="string" uniform="true" value="" uiname="Subset" uifolder="SSS"
            doc="Specifies trace subset for inclusion/exclusion when struck by a ray indirectly." />
     <input name="sssContinuationRays" type="integer" value="0" uiname="Continuation Rays" uifolder="SSS"
            doc="When enabled, ignores internal geometry and jumps to the last surface." />
     <input name="sssUnitLength" type="float" value="0.00328" uiname="Unit Length" uifolder="SSS"
-           doc="Specifies what unit length the scene is using. It is a multiplier on the mean free path or diffuse mean free path which is expressed in mm. The default value of 0.00328 converts between feet and mm." />
+           doc="This is the multiplier that converts between millimeters and scene units. Both mean free path and diffuse mean free path are specified in millimeters and this parameter is used for the unit conversion. The default value of 0.00328 converts millimeters to feet. For centimeter scene units, this would be 0.1, for meters it would be 0.001 etc." />
     <input name="mode" type="integer" uniform="true" enum="Reflection,Transmission,Reflection(with direct illumination)" enumvalues="0,1,2" value="0" uiname="Mode" uifolder="Advanced"
            doc="If the subsurface is enabled, Reflection: should be used when both the camera and the light are outside of the object. Reflection(with direct illumination): should be used when both the camera and the light are outside of the object. This mode also computes the direct illumination at the sss ray exit point. Transmission: should be used when the light is inside the object while the camera is outside. " />
     <input name="albedoInversionMethod" type="integer" enum="Pixar,Chiang" enumvalues="0,1" value="0" uiname="Albedo Inversion Method" uifolder="Advanced"
            doc="Decides which albedo inversion methods is used. Pixar: Does the Pixar Path Traced SSS default albedo inversion. Chiang: Does Chiang's albedo inversion (with no dmfp remapping). The look is closer to Arnold Standard Surface randomwalk." />
-    <input name="diffuseLobeName" type="string" uniform="true" value="diffuse" uiname="Diffuse Lobe Name" uifolder="Advanced"
-           doc="Defines the name that can be used in LPE AOVs for the diffuse lobe (when the SSS radius is null)." />
-    <input name="sssEntryLobeName" type="string" uniform="true" value="irradiance" uiname="SSS Entry Lobe Name" uifolder="Advanced"
-           doc="Defines the name that can be used in LPE AOVs for the SSS Entry lobe." />
-    <input name="sssExitLobeName" type="string" uniform="true" value="" uiname="SSS Exit Lobe Name" uifolder="Advanced"
-           doc="Defines the name that can be used in LPE AOVs for the SSS Exit lobe." />
-    <input name="sssId" type="integer" uniform="true" value="0" enum="0, 1" enumvalues="0, 1" uiname="SSS Id" uifolder="Advanced"
-           doc="SSS ID" />
-    <input name="matte" type="string" uniform="true" value="" uiname="Matte" uifolder="Advanced"
-           doc="Defines the name that can be used by the matte system, to output the weight of this lobe in the final material as an AOV." />
     <output name="out" type="BSDF" />
   </nodedef>
 
diff --git a/libraries/bxdf/lama/lama_surface.mtlx b/libraries/bxdf/lama/lama_surface.mtlx
index 4ffa9a63df..b7e84a510c 100644
--- a/libraries/bxdf/lama/lama_surface.mtlx
+++ b/libraries/bxdf/lama/lama_surface.mtlx
@@ -2,11 +2,11 @@
 <materialx version="1.39" colorspace="acescg">
   <nodedef name="ND_lama_surface" node="LamaSurface" nodegroup="pbr" version="1.0" isdefaultversion="true">
     <input name="materialFront" uiname="Material Front" type="BSDF" 
-           doc="This is the material that defines the front facing result." />
+           doc="Material used on the front side (as defined by the geometric normal)." />
     <input name="materialBack" uiname="Material Back" type="BSDF" 
-           doc="This is the material that defines the back facing result." />
+           doc="Material used on the back side (as defined by the geometric normal)." />
     <input name="presence" type="float" value="1.0"
-           doc="This connection allows you to define the visibility of a surface using a pattern connection." />
+           doc="Connect a mask here to apply a cutout pattern to your object. This is useful for cutouts like creating leaves and other thin, complex shapes. It can also be used as opacity for gray values for semi-opaque results when seen directly by the camera." />
     <output name="out" type="material" />
   </nodedef>
 
diff --git a/libraries/bxdf/lama/lama_translucent.mtlx b/libraries/bxdf/lama/lama_translucent.mtlx
index 9577e9c14f..ec3e968e09 100644
--- a/libraries/bxdf/lama/lama_translucent.mtlx
+++ b/libraries/bxdf/lama/lama_translucent.mtlx
@@ -9,10 +9,6 @@
            doc="Shading normal, typically defined by bump or normal mapping. Defaults to the smooth surface normal if not set." />
     <input name="energyCompensation" uiname="Energy Compensation" uifolder="Advanced" type="float" uniform="true" uimin="0.0" uimax="1.0" value="1.0"
            doc="Indicates how much energy should be added to compensate for the loss inherent to the Oren-Nayar model, ranging from no compensation at all, to the expected energy from multiple scattering between the micro-facets. This prevents overly dark results when roughness is high." />
-    <input name="lobeName" uiname="Lobe Name" uifolder="Advanced" type="string" uniform="true" value="diffuse"
-           doc="Defines the name that can be used in LPE AOVs for this lobe." />
-    <input name="matte" uiname="Matte" uifolder="Advanced" type="string" uniform="true" value=""
-           doc="Defines the name that can be used by the matte system, to output the weight of this lobe in the final material as an AOV." />
     <output name="out" type="BSDF" />
   </nodedef>
 
diff --git a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_conductor.mtlx b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_conductor.mtlx
index ee0852899f..87cc8211e7 100644
--- a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_conductor.mtlx
+++ b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_conductor.mtlx
@@ -8,7 +8,7 @@
     <input name="IOR" type="vector3" value="0.180000007153,0.419999986887,1.37000000477" />
     <input name="extinction" type="vector3" value="3.42000007629,2.34999990463,1.76999998093" />
     <input name="reflectivity" type="color3" value="0.9450, 0.7772, 0.3737" />
-    <input name="edgeColor" type="color3" value="0.9979, 0.9813, 0.7523" />
+    <input name="edgeColor" type="color3" value="0.7137, 0.7373, 0.4550" />
     <input name="roughness" type="float" value="0.1" />
     <input name="anisotropy" type="float" value="0.0" />
     <input name="anisotropyRotation" type="float" value="0.0" />
diff --git a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_emission.mtlx b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_emission.mtlx
index cae5722d1f..f21d752d20 100644
--- a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_emission.mtlx
+++ b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_emission.mtlx
@@ -3,7 +3,7 @@
 
   <!-- LamaEmission -->
   <LamaEmission name="LamaEmission" type="EDF">
-    <input name="color" type="color3" value="0.0, 1.0, 0.0" />
+    <input name="color" type="color3" value="0.0, 0.0, 0.0" />
   </LamaEmission>
   <surface name="LamaEmissionSurface" type="surfaceshader">
     <input name="edf" type="EDF" nodename="LamaEmission" />
diff --git a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_iridescence.mtlx b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_iridescence.mtlx
index a6bc228773..1125e34aa7 100644
--- a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_iridescence.mtlx
+++ b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_iridescence.mtlx
@@ -5,6 +5,7 @@
   <LamaIridescence name="LamaIridescence" type="BSDF">
     <input name="roughness" type="float" value="0.01" />
     <input name="anisotropy" type="float" value="0.0" />
+    <input name="anisotropyRotation" type="float" value="0.0" />
     <input name="relativeFilmThickness" type="float" value="0.5" />
     <input name="minFilmThickness" type="float" value="400.0" />
     <input name="maxFilmThickness" type="float" value="800.0" />
diff --git a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_translucent.mtlx b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_translucent.mtlx
index a5d9b80bc3..3b7fa03988 100644
--- a/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_translucent.mtlx
+++ b/resources/Materials/TestSuite/pbrlib/surfaceshader/lama/lama_translucent.mtlx
@@ -6,8 +6,6 @@
     <input name="color" type="color3" value="0.9, 0.0, 0.6" />
     <input name="roughness" type="float" value="0.0" />
     <input name="energyCompensation" type="float" value="1.0" />
-    <input name="lobeName" type="string" value="diffuse" />
-    <input name="matte" type="string" value="" />
   </LamaTranslucent>
   <surface name="LamaTranslucentSurface" type="surfaceshader">
     <input name="bsdf" type="BSDF" nodename="LamaTranslucent" />

From 67d2e2836fb3d7aee4ddd3cea273a9f85f82725a Mon Sep 17 00:00:00 2001
From: Jonathan Stone <jstone@lucasfilm.com>
Date: Thu, 8 Aug 2024 13:46:56 -0700
Subject: [PATCH 4/4] Fix Fresnel computation in GLSL transmission (#1962)

This changelist fixes an error in the Fresnel computation for GLSL transmission, improving the visual parity of transmissive materials across shading languages.

With this fix in place, the graph definition of LamaGeneralizedSchlick no longer requires a manual inversion of its F0 and F90 inputs for transmission, as this inversion is handled correctly in GLSL as well as OSL and MDL.
---
 .../bxdf/lama/lama_generalized_schlick.mtlx   | 12 +----
 .../genglsl/lib/mx_environment_fis.glsl       |  4 +-
 .../genglsl/mx_generalized_schlick_bsdf.glsl  |  2 +-
 .../pbrlib/bsdf/generalized_schlick.mtlx      | 54 +++++++------------
 4 files changed, 24 insertions(+), 48 deletions(-)

diff --git a/libraries/bxdf/lama/lama_generalized_schlick.mtlx b/libraries/bxdf/lama/lama_generalized_schlick.mtlx
index fd7c2ade5d..887273de45 100644
--- a/libraries/bxdf/lama/lama_generalized_schlick.mtlx
+++ b/libraries/bxdf/lama/lama_generalized_schlick.mtlx
@@ -63,14 +63,6 @@
       <input name="in2" type="color3" nodename="ior_multiply" />
       <input name="which" type="integer" interfacename="fresnelMode" />
     </switch>
-    <subtract name="transmission_color0" type="color3">
-      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="in2" type="color3" nodename="fresnel_mode_switch" />
-    </subtract>
-    <subtract name="transmission_color90" type="color3">
-      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="in2" type="color3" interfacename="reflectivity90" />
-    </subtract>
 
     <!-- Exponent -->
     <divide name="exponent" type="float">
@@ -132,8 +124,8 @@
     <!-- Transmission -->
     <generalized_schlick_bsdf name="transmission_bsdf" type="BSDF">
       <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" nodename="transmission_color0" />
-      <input name="color90" type="color3" nodename="transmission_color90" />
+      <input name="color0" type="color3" nodename="fresnel_mode_switch" />
+      <input name="color90" type="color3" interfacename="reflectivity90" />
       <input name="exponent" type="float" nodename="exponent" />
       <input name="roughness" type="vector2" nodename="roughness_anisotropic_squared_clamped" />
       <input name="normal" type="vector3" interfacename="normal" />
diff --git a/libraries/pbrlib/genglsl/lib/mx_environment_fis.glsl b/libraries/pbrlib/genglsl/lib/mx_environment_fis.glsl
index 0b28f3645f..1d61576650 100644
--- a/libraries/pbrlib/genglsl/lib/mx_environment_fis.glsl
+++ b/libraries/pbrlib/genglsl/lib/mx_environment_fis.glsl
@@ -43,8 +43,8 @@ vec3 mx_environment_radiance(vec3 N, vec3 V, vec3 X, vec2 alpha, int distributio
         // Compute the geometric term.
         float G = mx_ggx_smith_G2(NdotL, NdotV, avgAlpha);
 
-        // Compute the combined FG term, which is inverted for refraction.
-        vec3 FG = fd.refraction ? vec3(1.0) - (F * G) : F * G;
+        // Compute the combined FG term, which simplifies to inverted Fresnel for refraction.
+        vec3 FG = fd.refraction ? vec3(1.0) - F : F * G;
 
         // Add the radiance contribution of this sample.
         // From https://cdn2.unrealengine.com/Resources/files/2013SiggraphPresentationsNotes-26915738.pdf
diff --git a/libraries/pbrlib/genglsl/mx_generalized_schlick_bsdf.glsl b/libraries/pbrlib/genglsl/mx_generalized_schlick_bsdf.glsl
index 764412b90d..f4598dd0d0 100644
--- a/libraries/pbrlib/genglsl/mx_generalized_schlick_bsdf.glsl
+++ b/libraries/pbrlib/genglsl/mx_generalized_schlick_bsdf.glsl
@@ -66,7 +66,7 @@ void mx_generalized_schlick_bsdf_transmission(vec3 V, float weight, vec3 color0,
     {
         float avgF0 = dot(safeColor0, vec3(1.0 / 3.0));
         fd.ior = vec3(mx_f0_to_ior(avgF0));
-        bsdf.response = mx_surface_transmission(N, V, X, safeAlpha, distribution, fd, safeColor0) * weight;
+        bsdf.response = mx_surface_transmission(N, V, X, safeAlpha, distribution, fd, vec3(1.0)) * weight;
     }
 }
 
diff --git a/resources/Materials/TestSuite/pbrlib/bsdf/generalized_schlick.mtlx b/resources/Materials/TestSuite/pbrlib/bsdf/generalized_schlick.mtlx
index 05eb071558..bc31308a47 100644
--- a/resources/Materials/TestSuite/pbrlib/bsdf/generalized_schlick.mtlx
+++ b/resources/Materials/TestSuite/pbrlib/bsdf/generalized_schlick.mtlx
@@ -2,11 +2,8 @@
 <materialx version="1.39">
   <nodegraph name="schlick_bsdf">
     <generalized_schlick_bsdf name="schlick_R" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.7, 0.7, 0.7" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.8, 0.8, 0.8" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="R" />
     </generalized_schlick_bsdf>
     <surface name="surface_R" type="surfaceshader">
@@ -15,11 +12,8 @@
     <output name="R_out" type="surfaceshader" nodename="surface_R" />
 
     <generalized_schlick_bsdf name="schlick_T" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.7, 0.7, 0.7" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.2, 0.2, 0.2" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="T" />
     </generalized_schlick_bsdf>
     <surface name="surface_T" type="surfaceshader">
@@ -28,11 +22,8 @@
     <output name="T_out" type="surfaceshader" nodename="surface_T" />
 
     <generalized_schlick_bsdf name="schlick_RT" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.7, 0.7, 0.7" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.2, 0.2, 0.2" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="RT" />
     </generalized_schlick_bsdf>
     <surface name="surface_RT" type="surfaceshader">
@@ -50,11 +41,9 @@
     <output name="layer_RT_out" type="surfaceshader" nodename="surface_layer_RT" />
 
     <generalized_schlick_bsdf name="schlick_R2" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.5, 0.0, 0.0" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="0.0, 1.0, 0.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.8, 0.2, 0.2" />
+      <input name="color90" type="color3" value="0.2, 0.8, 0.2" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="R" />
     </generalized_schlick_bsdf>
     <surface name="surface_R2" type="surfaceshader">
@@ -63,11 +52,9 @@
     <output name="R2_out" type="surfaceshader" nodename="surface_R2" />
 
     <generalized_schlick_bsdf name="schlick_T2" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.5, 0.0, 0.0" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="0.0, 1.0, 0.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.8, 0.2, 0.2" />
+      <input name="color90" type="color3" value="0.2, 0.8, 0.2" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="T" />
     </generalized_schlick_bsdf>
     <surface name="surface_T2" type="surfaceshader">
@@ -76,11 +63,9 @@
     <output name="T2_out" type="surfaceshader" nodename="surface_T2" />
 
     <generalized_schlick_bsdf name="schlick_RT2" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="0.5, 0.0, 0.0" />
-      <input name="color82" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color90" type="color3" value="0.0, 1.0, 0.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.8, 0.2, 0.2" />
+      <input name="color90" type="color3" value="0.2, 0.8, 0.2" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="RT" />
     </generalized_schlick_bsdf>
     <surface name="surface_RT2" type="surfaceshader">
@@ -98,11 +83,10 @@
     <output name="layer_RT2_out" type="surfaceshader" nodename="surface_layer_RT2" />
 
     <generalized_schlick_bsdf name="schlick_R3" type="BSDF">
-      <input name="weight" type="float" value="1.0" />
-      <input name="color0" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="color82" type="color3" value="0.0, 0.0, 1.0" />
-      <input name="color90" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="exponent" type="float" value="5.0" />
+      <input name="color0" type="color3" value="0.8, 0.8, 0.8" />
+      <input name="color82" type="color3" value="0.2, 0.2, 0.8" />
+      <input name="color90" type="color3" value="0.8, 0.8, 0.8" />
+      <input name="roughness" type="vector2" value="0.02, 0.02" />
       <input name="scatter_mode" type="string" value="R" />
     </generalized_schlick_bsdf>
     <surface name="surface_R3" type="surfaceshader">