diff --git a/libraries/bxdf/genglsl/gltf_pbr.mtlx b/libraries/bxdf/genglsl/gltf_pbr.mtlx
deleted file mode 100644
index c60c566b0b..0000000000
--- a/libraries/bxdf/genglsl/gltf_pbr.mtlx
+++ /dev/null
@@ -1,330 +0,0 @@
-<?xml version="1.0"?>
-<materialx version="1.39">
-  <!-- An optimized graph implementation for hardware shading languages,
-       improving the effectiveness of dynamic branches. -->
-
-  <nodegraph name="IMPL_gltf_pbr_surfaceshader_optim" nodedef="ND_gltf_pbr_surfaceshader" target="genglsl">
-
-    <!-- Volume -->
-
-    <convert name="attenuation_color_vec" type="vector3">
-      <input name="in" type="color3" interfacename="attenuation_color" />
-    </convert>
-
-    <ln name="ln_attenuation_color_vec" type="vector3">
-      <input name="in" type="vector3" nodename="attenuation_color_vec" />
-    </ln>
-
-    <divide name="ln_attenuation_color_vec_over_distance" type="vector3">
-      <input name="in1" type="vector3" nodename="ln_attenuation_color_vec" />
-      <input name="in2" type="float" interfacename="attenuation_distance" />
-    </divide>
-
-    <multiply name="attenuation_coeff" type="vector3">
-      <input name="in1" type="vector3" nodename="ln_attenuation_color_vec_over_distance" />
-      <input name="in2" type="float" value="-1" />
-    </multiply>
-
-    <anisotropic_vdf name="isotropic_volume" type="VDF">
-      <!-- No scattering yet, so absorption_coeff == attenuation_coeff -->
-      <input name="absorption" type="vector3" nodename="attenuation_coeff" />
-      <input name="scattering" type="vector3" value="0, 0, 0" />
-      <input name="anisotropy" type="float" value="0" />
-    </anisotropic_vdf>
-
-    <!-- Base layer -->
-
-    <!-- Compute F0 and F90 of dielectric component -->
-    <subtract name="one_minus_ior" type="float">
-      <input name="in1" type="float" value="1" />
-      <input name="in2" type="float" interfacename="ior" />
-    </subtract>
-
-    <add name="one_plus_ior" type="float">
-      <input name="in1" type="float" value="1" />
-      <input name="in2" type="float" interfacename="ior" />
-    </add>
-
-    <divide name="ior_div" type="float">
-      <input name="in1" type="float" nodename="one_minus_ior" />
-      <input name="in2" type="float" nodename="one_plus_ior" />
-    </divide>
-
-    <multiply name="dielectric_f0_from_ior" type="float">
-      <input name="in1" type="float" nodename="ior_div" />
-      <input name="in2" type="float" nodename="ior_div" />
-    </multiply>
-
-    <multiply name="dielectric_f0_from_ior_specular_color" type="color3">
-      <input name="in1" type="color3" interfacename="specular_color" />
-      <input name="in2" type="float" nodename="dielectric_f0_from_ior" />
-    </multiply>
-
-    <min name="clamped_dielectric_f0_from_ior_specular_color" type="color3">
-      <input name="in1" type="color3" nodename="dielectric_f0_from_ior_specular_color" />
-      <input name="in2" type="float" value="1" />
-    </min>
-
-    <multiply name="dielectric_f0" type="color3">
-      <input name="in1" type="color3" nodename="clamped_dielectric_f0_from_ior_specular_color" />
-      <input name="in2" type="float" interfacename="specular" />
-    </multiply>
-
-    <multiply name="dielectric_f90" type="color3">
-      <input name="in1" type="color3" value="1, 1, 1" />
-      <input name="in2" type="float" interfacename="specular" />
-    </multiply>
-
-    <!-- Roughness -->
-
-    <combine2 name="roughness_uv" type="vector2">
-      <input name="in1" type="float" nodename="clamped_at" />
-      <input name="in2" type="float" nodename="clamped_ab" />
-    </combine2>
-    <clamp name="clamped_at" type="float">
-      <input name="in" type="float" nodename="at" />
-      <input name="low" type="float" value="0.00001" />
-      <input name="high" type="float" value="1.0" />
-    </clamp>
-    <clamp name="clamped_ab" type="float">
-      <input name="in" type="float" nodename="alpha_roughness" />
-      <input name="low" type="float" value="0.00001" />
-      <input name="high" type="float" value="1.0" />
-    </clamp>
-    <multiply name="alpha_roughness" type="float">
-      <input name="in1" type="float" interfacename="roughness" />
-      <input name="in2" type="float" interfacename="roughness" />
-    </multiply>
-    <multiply name="strength_2" type="float">
-      <input name="in1" type="float" interfacename="anisotropy_strength" />
-      <input name="in2" type="float" interfacename="anisotropy_strength" />
-    </multiply>
-    <mix name="at" type="float">
-      <input name="fg" type="float" value="1" />
-      <input name="bg" type="float" nodename="alpha_roughness" />
-      <input name="mix" type="float" nodename="strength_2" />
-    </mix>
-
-    <!-- Dielectric -->
-    <invert name="transmission_inv" type="float">
-      <input name="in" type="float" interfacename="transmission" />
-    </invert>
-    <oren_nayar_diffuse_bsdf name="diffuse_bsdf" type="BSDF">
-      <input name="weight" type="float" nodename="transmission_inv" />
-      <input name="color" type="color3" interfacename="base_color" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </oren_nayar_diffuse_bsdf>
-    <dielectric_bsdf name="transmission_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="transmission" />
-      <input name="tint" type="color3" interfacename="base_color" />
-      <input name="ior" type="float" interfacename="ior" />
-      <input name="roughness" type="vector2" nodename="roughness_uv" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="selected_tangent" />
-      <input name="scatter_mode" type="string" value="T" />
-    </dielectric_bsdf>
-    <add name="transmission_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="diffuse_bsdf" />
-      <input name="in2" type="BSDF" nodename="transmission_bsdf" />
-    </add>
-    <invert name="iridescence_inv" type="float">
-      <input name="in" type="float" interfacename="iridescence" />
-    </invert>
-    <generalized_schlick_bsdf name="reflection_bsdf" type="BSDF">
-      <input name="weight" type="float" nodename="iridescence_inv" />
-      <input name="color0" type="color3" nodename="dielectric_f0" />
-      <input name="color90" type="color3" nodename="dielectric_f90" />
-      <input name="roughness" type="vector2" nodename="roughness_uv" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="selected_tangent" />
-      <input name="scatter_mode" type="string" value="R" />
-    </generalized_schlick_bsdf>
-    <generalized_schlick_bsdf name="reflection_bsdf_tf" type="BSDF">
-      <input name="weight" type="float" interfacename="iridescence" />
-      <input name="color0" type="color3" nodename="dielectric_f0" />
-      <input name="color90" type="color3" nodename="dielectric_f90" />
-      <input name="roughness" type="vector2" nodename="roughness_uv" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="selected_tangent" />
-      <input name="scatter_mode" type="string" value="R" />
-      <input name="thinfilm_thickness" type="float" interfacename="iridescence_thickness" />
-      <input name="thinfilm_ior" type="float" interfacename="iridescence_ior" />
-    </generalized_schlick_bsdf>
-    <add name="reflection_bsdf_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="reflection_bsdf" />
-      <input name="in2" type="BSDF" nodename="reflection_bsdf_tf" />
-    </add>
-    <layer name="dielectric_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="reflection_bsdf_blend" />
-      <input name="base" type="BSDF" nodename="transmission_blend" />
-    </layer>
-
-    <!-- Metal -->
-    <generalized_schlick_bsdf name="metal_bsdf" type="BSDF">
-      <input name="weight" type="float" nodename="iridescence_inv" />
-      <input name="color0" type="color3" interfacename="base_color" />
-      <input name="color90" type="color3" value="1, 1, 1" />
-      <input name="roughness" type="vector2" nodename="roughness_uv" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="selected_tangent" />
-    </generalized_schlick_bsdf>
-    <generalized_schlick_bsdf name="metal_bsdf_tf" type="BSDF">
-      <input name="weight" type="float" interfacename="iridescence" />
-      <input name="color0" type="color3" interfacename="base_color" />
-      <input name="color90" type="color3" value="1, 1, 1" />
-      <input name="roughness" type="vector2" nodename="roughness_uv" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="selected_tangent" />
-      <input name="thinfilm_thickness" type="float" interfacename="iridescence_thickness" />
-      <input name="thinfilm_ior" type="float" interfacename="iridescence_ior" />
-    </generalized_schlick_bsdf>
-    <add name="metal_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="metal_bsdf" />
-      <input name="in2" type="BSDF" nodename="metal_bsdf_tf" />
-    </add>
-
-    <!-- Dielectric/metal mix -->
-    <mix name="base_mix" type="BSDF">
-      <input name="bg" type="BSDF" nodename="dielectric_layer" />
-      <input name="fg" type="BSDF" nodename="metal_blend" />
-      <input name="mix" type="float" interfacename="metallic" />
-    </mix>
-
-    <!-- Sheen layer -->
-
-    <!-- Compute sheen intensity = max(sheen_color.r, sheen_color.g, sheen_color.b) -->
-    <extract name="sheen_color_r" type="float">
-      <input name="in" type="color3" interfacename="sheen_color" />
-      <input name="index" type="integer" value="0" />
-    </extract>
-
-    <extract name="sheen_color_g" type="float">
-      <input name="in" type="color3" interfacename="sheen_color" />
-      <input name="index" type="integer" value="1" />
-    </extract>
-
-    <extract name="sheen_color_b" type="float">
-      <input name="in" type="color3" interfacename="sheen_color" />
-      <input name="index" type="integer" value="2" />
-    </extract>
-
-    <max name="sheen_color_max_rg" type="float">
-      <input name="in1" type="float" nodename="sheen_color_r" />
-      <input name="in2" type="float" nodename="sheen_color_g" />
-    </max>
-
-    <max name="sheen_intensity" type="float">
-      <input name="in1" type="float" nodename="sheen_color_max_rg" />
-      <input name="in2" type="float" nodename="sheen_color_b" />
-    </max>
-
-    <multiply name="sheen_roughness_sq" type="float">
-      <input name="in1" type="float" interfacename="sheen_roughness" />
-      <input name="in2" type="float" interfacename="sheen_roughness" />
-    </multiply>
-
-    <divide name="sheen_color_normalized" type="color3">
-      <input name="in1" type="color3" interfacename="sheen_color" />
-      <input name="in2" type="float" nodename="sheen_intensity" />
-    </divide>
-
-    <sheen_bsdf name="sheen_bsdf" type="BSDF">
-      <input name="weight" type="float" nodename="sheen_intensity" />
-      <input name="color" type="color3" nodename="sheen_color_normalized" />
-      <input name="roughness" type="float" nodename="sheen_roughness_sq" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </sheen_bsdf>
-
-    <layer name="sheen_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="sheen_bsdf" />
-      <input name="base" type="BSDF" nodename="base_mix" />
-    </layer>
-
-    <!-- Clearcoat -->
-
-    <roughness_anisotropy name="clearcoat_roughness_uv" type="vector2">
-      <input name="roughness" type="float" interfacename="clearcoat_roughness" />
-    </roughness_anisotropy>
-
-    <dielectric_bsdf name="clearcoat_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="clearcoat" />
-      <input name="roughness" type="vector2" nodename="clearcoat_roughness_uv" />
-      <input name="ior" type="float" value="1.5" />
-      <input name="normal" type="vector3" interfacename="clearcoat_normal" />
-      <input name="tangent" type="vector3" interfacename="tangent" />
-    </dielectric_bsdf>
-
-    <layer name="clearcoat_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="clearcoat_bsdf" />
-      <input name="base" type="BSDF" nodename="sheen_layer" />
-    </layer>
-
-    <!-- Emission -->
-
-    <multiply name="emission_color" type="color3">
-      <input name="in1" type="color3" interfacename="emissive" />
-      <input name="in2" type="float" interfacename="emissive_strength" />
-    </multiply>
-
-    <uniform_edf name="emission" type="EDF">
-      <input name="color" type="color3" nodename="emission_color" />
-    </uniform_edf>
-
-    <!-- Alpha -->
-
-    <ifgreatereq name="opacity_mask_cutoff" type="float">
-      <input name="value1" type="float" interfacename="alpha" />
-      <input name="value2" type="float" interfacename="alpha_cutoff" />
-      <input name="in1" type="float" value="1" />
-      <input name="in2" type="float" value="0" />
-    </ifgreatereq>
-
-    <ifequal name="opacity_mask" type="float">
-      <input name="value1" type="integer" interfacename="alpha_mode" />
-      <input name="value2" type="integer" value="1" />
-      <input name="in1" type="float" nodename="opacity_mask_cutoff" />
-      <input name="in2" type="float" interfacename="alpha" />
-    </ifequal>
-
-    <ifequal name="opacity" type="float">
-      <input name="value1" type="integer" interfacename="alpha_mode" />
-      <input name="value2" type="integer" value="0" />
-      <input name="in1" type="float" value="1" />
-      <input name="in2" type="float" nodename="opacity_mask" />
-    </ifequal>
-
-    <!-- Anisotropy -->
-
-    <multiply name="rad_2_deg" type="float">
-      <input name="in1" type="float" interfacename="anisotropy_rotation" />
-      <input name="in2" type="float" value="-57.295780" />
-    </multiply>
-    <rotate3d name="rotate_tangent" type="vector3">
-      <input name="in" type="vector3" interfacename="tangent" />
-      <input name="amount" type="float" nodename="rad_2_deg" />
-      <input name="axis" type="vector3" interfacename="normal" />
-    </rotate3d>
-    <normalize name="normalize_tangent" type="vector3">
-      <input name="in" type="vector3" nodename="rotate_tangent" />
-    </normalize>
-    <absval name="abs_anisotropy_rotation" type="float">
-      <input name="in" type="float" interfacename="anisotropy_rotation" />
-    </absval>
-    <ifgreater name="selected_tangent" type="vector3">
-      <input name="value1" type="float" nodename="abs_anisotropy_rotation" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="vector3" nodename="normalize_tangent" />
-      <input name="in2" type="vector3" interfacename="tangent" />
-    </ifgreater>
-
-    <!-- Surface -->
-
-    <surface name="shader_constructor" type="surfaceshader">
-      <input name="bsdf" type="BSDF" nodename="clearcoat_layer" />
-      <input name="edf" type="EDF" nodename="emission" />
-      <input name="opacity" type="float" nodename="opacity" />
-    </surface>
-    <output name="out" type="surfaceshader" nodename="shader_constructor" />
-  </nodegraph>
-
-</materialx>
diff --git a/libraries/bxdf/genglsl/open_pbr_surface.mtlx b/libraries/bxdf/genglsl/open_pbr_surface.mtlx
deleted file mode 100644
index 85d8717d4e..0000000000
--- a/libraries/bxdf/genglsl/open_pbr_surface.mtlx
+++ /dev/null
@@ -1,596 +0,0 @@
-<?xml version="1.0"?>
-<materialx version="1.39">
-  <!-- An optimized graph implementation for hardware shading languages,
-       improving the effectiveness of dynamic branches. -->
-
-  <nodegraph name="NG_open_pbr_surface_surfaceshader_optim" nodedef="ND_open_pbr_surface_surfaceshader" target="genglsl">
-
-    <!-- Roughening due to coat-->
-    <power name="coat_roughness_to_power_4" type="float">
-      <input name="in1" type="float" interfacename="coat_roughness" />
-      <input name="in2" type="float" value="4.0" />
-    </power>
-    <multiply name="two_times_coat_roughness_to_power_4" type="float">
-      <input name="in1" type="float" nodename="coat_roughness_to_power_4" />
-      <input name="in2" type="float" value="2.0" />
-    </multiply>
-    <power name="specular_roughness_to_power_4" type="float">
-      <input name="in1" type="float" interfacename="specular_roughness" />
-      <input name="in2" type="float" value="4.0" />
-    </power>
-    <add name="add_coat_and_spec_roughnesses_to_power_4" type="float">
-      <input name="in1" type="float" nodename="two_times_coat_roughness_to_power_4" />
-      <input name="in2" type="float" nodename="specular_roughness_to_power_4" />
-    </add>
-    <min name="min_1_add_coat_and_spec_roughnesses_to_power_4" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="add_coat_and_spec_roughnesses_to_power_4" />
-    </min>
-    <power name="coat_affected_specular_roughness" type="float">
-      <input name="in1" type="float" nodename="min_1_add_coat_and_spec_roughnesses_to_power_4" />
-      <input name="in2" type="float" value="0.25" />
-    </power>
-    <mix name="effective_specular_roughness" type="float">
-      <input name="fg" type="float" nodename="coat_affected_specular_roughness" />
-      <input name="bg" type="float" interfacename="specular_roughness" />
-      <input name="mix" type="float" interfacename="coat_weight" />
-    </mix>
-
-    <!-- Calculate main specular roughness -->
-    <open_pbr_anisotropy name="main_roughness" type="vector2">
-      <input name="roughness" type="float" nodename="effective_specular_roughness" />
-      <input name="anisotropy" type="float" interfacename="specular_roughness_anisotropy" />
-    </open_pbr_anisotropy>
-
-    <!-- Subsurface (thin-walled) -->
-    <max name="subsurface_color_nonnegative" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_color" />
-      <input name="in2" type="float" value="0.0" />
-    </max>
-    <oren_nayar_diffuse_bsdf name="subsurface_thin_walled_reflection_bsdf" type="BSDF">
-      <input name="color" type="color3" nodename="subsurface_color_nonnegative" />
-      <input name="roughness" type="float" interfacename="base_diffuse_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-    </oren_nayar_diffuse_bsdf>
-    <subtract name="one_minus_subsurface_scatter_anisotropy" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="subsurface_scatter_anisotropy" />
-    </subtract>
-    <multiply name="subsurface_thin_walled_brdf_factor" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_color" />
-      <input name="in2" type="float" nodename="one_minus_subsurface_scatter_anisotropy" />
-    </multiply>
-    <multiply name="subsurface_thin_walled_reflection" type="BSDF">
-      <input name="in1" type="BSDF" nodename="subsurface_thin_walled_reflection_bsdf" />
-      <input name="in2" type="color3" nodename="subsurface_thin_walled_brdf_factor" />
-    </multiply>
-    <translucent_bsdf name="subsurface_thin_walled_transmission_bsdf" type="BSDF">
-      <input name="color" type="color3" nodename="subsurface_color_nonnegative" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-    </translucent_bsdf>
-    <add name="one_plus_subsurface_scatter_anisotropy" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="subsurface_scatter_anisotropy" />
-    </add>
-    <multiply name="subsurface_thin_walled_btdf_factor" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_color" />
-      <input name="in2" type="float" nodename="one_plus_subsurface_scatter_anisotropy" />
-    </multiply>
-    <multiply name="subsurface_thin_walled_transmission" type="BSDF">
-      <input name="in1" type="BSDF" nodename="subsurface_thin_walled_transmission_bsdf" />
-      <input name="in2" type="color3" nodename="subsurface_thin_walled_btdf_factor" />
-    </multiply>
-    <mix name="subsurface_thin_walled" type="BSDF">
-      <input name="fg" type="BSDF" nodename="subsurface_thin_walled_reflection" />
-      <input name="bg" type="BSDF" nodename="subsurface_thin_walled_transmission" />
-      <input name="mix" type="float" value="0.5" />
-    </mix>
-
-    <!-- Subsurface (non-thin-walled) -->
-    <multiply name="subsurface_radius_scaled" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_radius_scale" />
-      <input name="in2" type="float" interfacename="subsurface_radius" />
-    </multiply>
-    <subsurface_bsdf name="subsurface_bsdf" type="BSDF">
-      <input name="color" type="color3" nodename="subsurface_color_nonnegative" />
-      <input name="radius" type="color3" nodename="subsurface_radius_scaled" />
-      <input name="anisotropy" type="float" interfacename="subsurface_scatter_anisotropy" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-    </subsurface_bsdf>
-
-    <!-- Opaque Dielectric Base -->
-    <max name="base_color_nonnegative" type="color3">
-      <input name="in1" type="color3" interfacename="base_color" />
-      <input name="in2" type="float" value="0.0" />
-    </max>
-    <oren_nayar_diffuse_bsdf name="diffuse_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="base_weight" />
-      <input name="color" type="color3" nodename="base_color_nonnegative" />
-      <input name="roughness" type="float" interfacename="base_diffuse_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="energy_compensation" type="boolean" value="true" />
-    </oren_nayar_diffuse_bsdf>
-    <convert name="subsurface_selector" type="float">
-      <input name="in" type="boolean" interfacename="geometry_thin_walled" />
-    </convert>
-    <mix name="selected_subsurface" type="BSDF">
-      <input name="fg" type="BSDF" nodename="subsurface_thin_walled" />
-      <input name="bg" type="BSDF" nodename="subsurface_bsdf" />
-      <input name="mix" type="float" nodename="subsurface_selector" />
-    </mix>
-    <mix name="opaque_base" type="BSDF">
-      <input name="fg" type="BSDF" nodename="selected_subsurface" />
-      <input name="bg" type="BSDF" nodename="diffuse_bsdf" />
-      <input name="mix" type="float" interfacename="subsurface_weight" />
-    </mix>
-
-    <!-- Dielectric Base VDF -->
-    <convert name="transmission_color_vector" type="vector3">
-      <input name="in" type="color3" interfacename="transmission_color" />
-    </convert>
-    <ln name="transmission_color_ln" type="vector3">
-      <input name="in" type="vector3" nodename="transmission_color_vector" />
-    </ln>
-    <multiply name="extinction_coeff_denom" type="vector3">
-      <input name="in1" type="vector3" nodename="transmission_color_ln" />
-      <input name="in2" type="float" value="-1.0" />
-    </multiply>
-    <convert name="transmission_depth_vector" type="vector3">
-      <input name="in" type="float" interfacename="transmission_depth" />
-    </convert>
-    <divide name="extinction_coeff" type="vector3">
-      <input name="in1" type="vector3" nodename="extinction_coeff_denom" />
-      <input name="in2" type="vector3" nodename="transmission_depth_vector" />
-    </divide>
-    <convert name="transmission_scatter_vector" type="vector3">
-      <input name="in" type="color3" interfacename="transmission_scatter" />
-    </convert>
-    <divide name="scattering_coeff" type="vector3">
-      <input name="in1" type="vector3" nodename="transmission_scatter_vector" />
-      <input name="in2" type="vector3" nodename="transmission_depth_vector" />
-    </divide>
-    <subtract name="absorption_coeff" type="vector3">
-      <input name="in1" type="vector3" nodename="extinction_coeff" />
-      <input name="in2" type="vector3" nodename="scattering_coeff" />
-    </subtract>
-    <extract name="absorption_coeff_x" type="float">
-      <input name="in" type="vector3" nodename="absorption_coeff" />
-      <input name="index" type="integer" value="0" />
-    </extract>
-    <extract name="absorption_coeff_y" type="float">
-      <input name="in" type="vector3" nodename="absorption_coeff" />
-      <input name="index" type="integer" value="1" />
-    </extract>
-    <extract name="absorption_coeff_z" type="float">
-      <input name="in" type="vector3" nodename="absorption_coeff" />
-      <input name="index" type="integer" value="2" />
-    </extract>
-    <min name="absorption_coeff_min_x_y" type="float">
-      <input name="in1" type="float" nodename="absorption_coeff_x" />
-      <input name="in2" type="float" nodename="absorption_coeff_y" />
-    </min>
-    <min name="absorption_coeff_min" type="float">
-      <input name="in1" type="float" nodename="absorption_coeff_min_x_y" />
-      <input name="in2" type="float" nodename="absorption_coeff_z" />
-    </min>
-    <convert name="absorption_coeff_min_vector" type="vector3">
-      <input name="in" type="float" nodename="absorption_coeff_min" />
-    </convert>
-    <subtract name="absorption_coeff_shifted" type="vector3">
-      <input name="in1" type="vector3" nodename="absorption_coeff" />
-      <input name="in2" type="vector3" nodename="absorption_coeff_min_vector" />
-    </subtract>
-    <ifgreater name="if_absorption_coeff_shifted" type="vector3">
-      <input name="value1" type="float" value="0.0" />
-      <input name="value2" type="float" nodename="absorption_coeff_min" />
-      <input name="in1" type="vector3" nodename="absorption_coeff_shifted" />
-      <input name="in2" type="vector3" nodename="absorption_coeff" />
-    </ifgreater>
-    <ifgreater name="if_volume_absorption" type="vector3">
-      <input name="value1" type="float" interfacename="transmission_depth" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="vector3" nodename="if_absorption_coeff_shifted" />
-      <input name="in2" type="vector3" value="0.0,0.0,0.0" />
-    </ifgreater>
-    <ifgreater name="if_volume_scattering" type="vector3">
-      <input name="value1" type="float" interfacename="transmission_depth" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="vector3" nodename="scattering_coeff" />
-      <input name="in2" type="vector3" value="0.0,0.0,0.0" />
-    </ifgreater>
-    <anisotropic_vdf name="dielectric_volume" type="VDF">
-      <input name="absorption" type="vector3" nodename="if_volume_absorption" />
-      <input name="scattering" type="vector3" nodename="if_volume_scattering" />
-      <input name="anisotropy" type="float" interfacename="transmission_scatter_anisotropy" />
-    </anisotropic_vdf>
-
-    <!-- Thin-film Thickness -->
-    <multiply name="thin_film_thickness_nm" type="float">
-      <input name="in1" type="float" interfacename="thin_film_thickness" />
-      <input name="in2" type="float" value="1000.0" />
-    </multiply>
-
-    <!-- Dielectric Base -->
-    <!-- apply IOR ratio inversion method to avoid TIR artifact (as in Coat TIR section of spec) -->
-    <divide name="specular_to_coat_ior_ratio" type="float">
-      <input name="in1" type="float" interfacename="specular_ior" />
-      <input name="in2" type="float" interfacename="coat_ior" />
-    </divide>
-    <divide name="coat_to_specular_ior_ratio" type="float">
-      <input name="in1" type="float" interfacename="coat_ior" />
-      <input name="in2" type="float" interfacename="specular_ior" />
-    </divide>
-    <ifgreater name="specular_to_coat_ior_ratio_tir_fix" type="float">
-      <input name="value1" type="float" nodename="specular_to_coat_ior_ratio" />
-      <input name="value2" type="float" value="1.0" />
-      <input name="in1" type="float" nodename="specular_to_coat_ior_ratio" />
-      <input name="in2" type="float" nodename="coat_to_specular_ior_ratio" />
-    </ifgreater>
-    <mix name="eta_s" type="float">
-      <input name="fg" type="float" nodename="specular_to_coat_ior_ratio_tir_fix" />
-      <input name="bg" type="float" interfacename="specular_ior" />
-      <input name="mix" type="float" interfacename="coat_weight" />
-    </mix>
-    <subtract name="eta_s_minus_one" type="float">
-      <input name="in1" type="float" nodename="eta_s" />
-      <input name="in2" type="float" value="1.0" />
-    </subtract>
-    <add name="eta_s_plus_one" type="float">
-      <input name="in1" type="float" nodename="eta_s" />
-      <input name="in2" type="float" value="1.0" />
-    </add>
-    <divide name="specular_F0_sqrt" type="float">
-      <input name="in1" type="float" nodename="eta_s_minus_one" />
-      <input name="in2" type="float" nodename="eta_s_plus_one" />
-    </divide>
-    <multiply name="specular_F0" type="float">
-      <input name="in1" type="float" nodename="specular_F0_sqrt" />
-      <input name="in2" type="float" nodename="specular_F0_sqrt" />
-    </multiply>
-    <multiply name="scaled_specular_F0" type="float">
-      <input name="in1" type="float" interfacename="specular_weight" />
-      <input name="in2" type="float" nodename="specular_F0" />
-    </multiply>
-    <clamp name="scaled_specular_F0_clamped" type="float">
-      <input name="in" type="float" nodename="scaled_specular_F0" />
-      <input name="low" type="float" value="0.0" />
-      <input name="high" type="float" value="0.99999" />
-    </clamp>
-    <sqrt name="sqrt_scaled_specular_F0" type="float">
-      <input name="in" type="float" nodename="scaled_specular_F0_clamped" />
-    </sqrt>
-    <sign name="sign_eta_s_minus_one" type="float">
-      <input name="in" type="float" nodename="eta_s_minus_one" />
-    </sign>
-    <multiply name="modulated_eta_s_epsilon" type="float">
-      <input name="in1" type="float" nodename="sign_eta_s_minus_one" />
-      <input name="in2" type="float" nodename="sqrt_scaled_specular_F0" />
-    </multiply>
-    <subtract name="one_minus_modulated_eta_s_epsilon" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="modulated_eta_s_epsilon" />
-    </subtract>
-    <add name="one_plus_modulated_eta_s_epsilon" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="modulated_eta_s_epsilon" />
-    </add>
-    <divide name="modulated_eta_s" type="float">
-      <input name="in1" type="float" nodename="one_plus_modulated_eta_s_epsilon" />
-      <input name="in2" type="float" nodename="one_minus_modulated_eta_s_epsilon" />
-    </divide>
-    <ifgreater name="if_transmission_tint" type="color3">
-      <input name="value1" type="float" interfacename="transmission_depth" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="in2" type="color3" interfacename="transmission_color" />
-    </ifgreater>
-    <dielectric_bsdf name="dielectric_transmission" type="BSDF">
-      <input name="tint" type="color3" nodename="if_transmission_tint" />
-      <input name="ior" type="float" nodename="modulated_eta_s" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_tangent" />
-      <input name="scatter_mode" type="string" value="T" />
-    </dielectric_bsdf>
-    <layer name="dielectric_volume_transmission" type="BSDF">
-      <input name="top" type="BSDF" nodename="dielectric_transmission" />
-      <input name="base" type="VDF" nodename="dielectric_volume" />
-    </layer>
-    <mix name="dielectric_substrate" type="BSDF">
-      <input name="fg" type="BSDF" nodename="dielectric_volume_transmission" />
-      <input name="bg" type="BSDF" nodename="opaque_base" />
-      <input name="mix" type="float" interfacename="transmission_weight" />
-    </mix>
-    <invert name="thin_film_weight_inv" type="float">
-      <input name="in" type="float" interfacename="thin_film_weight" />
-    </invert>
-    <dielectric_bsdf name="dielectric_reflection" type="BSDF">
-      <input name="weight" type="float" nodename="thin_film_weight_inv" />
-      <input name="tint" type="color3" interfacename="specular_color" />
-      <input name="ior" type="float" nodename="modulated_eta_s" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_tangent" />
-      <input name="scatter_mode" type="string" value="R" />
-    </dielectric_bsdf>
-    <dielectric_bsdf name="dielectric_reflection_tf" type="BSDF">
-      <input name="weight" type="float" interfacename="thin_film_weight" />
-      <input name="tint" type="color3" interfacename="specular_color" />
-      <input name="ior" type="float" nodename="modulated_eta_s" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_tangent" />
-      <input name="scatter_mode" type="string" value="R" />
-      <input name="thinfilm_thickness" type="float" nodename="thin_film_thickness_nm" />
-      <input name="thinfilm_ior" type="float" interfacename="thin_film_ior" />
-    </dielectric_bsdf>
-    <add name="dielectric_reflection_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="dielectric_reflection" />
-      <input name="in2" type="BSDF" nodename="dielectric_reflection_tf" />
-    </add>
-    <layer name="dielectric_base" type="BSDF">
-      <input name="top" type="BSDF" nodename="dielectric_reflection_blend" />
-      <input name="base" type="BSDF" nodename="dielectric_substrate" />
-    </layer>
-
-    <!-- Metal Layer -->
-    <multiply name="metal_reflectivity" type="color3">
-      <input name="in1" type="color3" interfacename="base_color" />
-      <input name="in2" type="float" interfacename="base_weight" />
-    </multiply>
-    <multiply name="metal_edgecolor" type="color3">
-      <input name="in1" type="color3" interfacename="specular_color" />
-      <input name="in2" type="float" interfacename="specular_weight" />
-    </multiply>
-    <multiply name="specular_weight_tf" type="float">
-      <input name="in1" type="float" interfacename="specular_weight" />
-      <input name="in2" type="float" interfacename="thin_film_weight" />
-    </multiply>
-    <multiply name="specular_weight_tf_inv" type="float">
-      <input name="in1" type="float" interfacename="specular_weight" />
-      <input name="in2" type="float" nodename="thin_film_weight_inv" />
-    </multiply>
-    <generalized_schlick_bsdf name="metal_bsdf" type="BSDF">
-      <input name="weight" type="float" nodename="specular_weight_tf_inv" />
-      <input name="color0" type="color3" nodename="metal_reflectivity" />
-      <input name="color82" type="color3" nodename="metal_edgecolor" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_tangent" />
-    </generalized_schlick_bsdf>
-    <generalized_schlick_bsdf name="metal_bsdf_tf" type="BSDF">
-      <input name="weight" type="float" nodename="specular_weight_tf" />
-      <input name="color0" type="color3" nodename="metal_reflectivity" />
-      <input name="color82" type="color3" nodename="metal_edgecolor" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_tangent" />
-      <input name="thinfilm_thickness" type="float" nodename="thin_film_thickness_nm" />
-      <input name="thinfilm_ior" type="float" interfacename="thin_film_ior" />
-    </generalized_schlick_bsdf>
-    <add name="metal_bsdf_tf_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="metal_bsdf" />
-      <input name="in2" type="BSDF" nodename="metal_bsdf_tf" />
-    </add>
-    <mix name="base_substrate" type="BSDF">
-      <input name="fg" type="BSDF" nodename="metal_bsdf_tf_blend" />
-      <input name="bg" type="BSDF" nodename="dielectric_base" />
-      <input name="mix" type="float" interfacename="base_metalness" />
-    </mix>
-
-    <!-- Coat darkening calculation  -->
-    <!-- approximate Kcoat, "internal diffuse reflection coefficient" of coat  -->
-    <subtract name="one_minus_coat_F0" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="coat_ior_to_F0" />
-    </subtract>
-    <multiply name="coat_ior_sqr" type="float">
-      <input name="in1" type="float" interfacename="coat_ior" />
-      <input name="in2" type="float" interfacename="coat_ior" />
-    </multiply>
-    <divide name="one_minus_coat_F0_over_eta2" type="float">
-      <input name="in1" type="float" nodename="one_minus_coat_F0" />
-      <input name="in2" type="float" nodename="coat_ior_sqr" />
-    </divide>
-    <subtract name="Kcoat" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="one_minus_coat_F0_over_eta2" />
-    </subtract>
-    <!-- approximate base metal albedo estimate, Emetal  -->
-    <multiply name="Emetal" type="color3">
-      <input name="in1" type="color3" interfacename="base_color" />
-      <input name="in2" type="float" interfacename="specular_weight" />
-    </multiply>
-    <!-- approximate base dielectric albedo estimate, Edielectric  -->
-    <mix name="Edielectric" type="color3">
-      <input name="fg" type="color3" interfacename="subsurface_color" />
-      <input name="bg" type="color3" interfacename="base_color" />
-      <input name="mix" type="float" interfacename="subsurface_weight" />
-    </mix>
-    <!-- thus calculate overall base albedo estimate approximation, Ebase  -->
-    <mix name="Ebase" type="color3">
-      <input name="fg" type="color3" nodename="Emetal" />
-      <input name="bg" type="color3" nodename="Edielectric" />
-      <input name="mix" type="float" interfacename="base_metalness" />
-    </mix>
-    <!-- final base darkening factor due to coat:  base_darkening = (1 - Kcoat) / (1 - Ebase*Kcoat)  -->
-    <multiply name="Ebase_Kcoat" type="color3">
-      <input name="in1" type="color3" nodename="Ebase" />
-      <input name="in2" type="float" nodename="Kcoat" />
-    </multiply>
-    <subtract name="one_minus_Kcoat" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="Kcoat" />
-    </subtract>
-    <subtract name="one_minus_Ebase_Kcoat" type="color3">
-      <input name="in1" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="in2" type="color3" nodename="Ebase_Kcoat" />
-    </subtract>
-    <convert name="one_minus_Kcoat_color" type="color3">
-      <input name="in" type="float" nodename="one_minus_Kcoat" />
-    </convert>
-    <divide name="base_darkening" type="color3">
-      <input name="in1" type="color3" nodename="one_minus_Kcoat_color" />
-      <input name="in2" type="color3" nodename="one_minus_Ebase_Kcoat" />
-    </divide>
-    <multiply name="coat_weight_times_coat_darkening" type="float">
-      <input name="in1" type="float" interfacename="coat_weight" />
-      <input name="in2" type="float" interfacename="coat_darkening" />
-    </multiply>
-    <mix name="modulated_base_darkening" type="color3">
-      <input name="fg" type="color3" nodename="base_darkening" />
-      <input name="bg" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="mix" type="float" nodename="coat_weight_times_coat_darkening" />
-    </mix>
-    <multiply name="darkened_base_substrate" type="BSDF">
-      <input name="in1" type="BSDF" nodename="base_substrate" />
-      <input name="in2" type="color3" nodename="modulated_base_darkening" />
-    </multiply>
-
-    <!-- Coat Layer -->
-    <mix name="coat_attenuation" type="color3">
-      <input name="fg" type="color3" interfacename="coat_color" />
-      <input name="bg" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="mix" type="float" interfacename="coat_weight" />
-    </mix>
-    <multiply name="coat_substrate_attenuated" type="BSDF">
-      <input name="in1" type="BSDF" nodename="darkened_base_substrate" />
-      <input name="in2" type="color3" nodename="coat_attenuation" />
-    </multiply>
-
-    <open_pbr_anisotropy name="coat_roughness_vector" type="vector2">
-      <input name="roughness" type="float" interfacename="coat_roughness" />
-      <input name="anisotropy" type="float" interfacename="coat_roughness_anisotropy" />
-    </open_pbr_anisotropy>
-    <dielectric_bsdf name="coat_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="coat_weight" />
-      <input name="ior" type="float" interfacename="coat_ior" />
-      <input name="roughness" type="vector2" nodename="coat_roughness_vector" />
-      <input name="normal" type="vector3" interfacename="geometry_coat_normal" />
-      <input name="tangent" type="vector3" interfacename="geometry_coat_tangent" />
-      <input name="scatter_mode" type="string" value="R" />
-    </dielectric_bsdf>
-    <layer name="coat_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="coat_bsdf" />
-      <input name="base" type="BSDF" nodename="coat_substrate_attenuated" />
-    </layer>
-
-    <!-- Fuzz Layer -->
-    <sheen_bsdf name="fuzz_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="fuzz_weight" />
-      <input name="color" type="color3" interfacename="fuzz_color" />
-      <input name="roughness" type="float" interfacename="fuzz_roughness" />
-      <input name="normal" type="vector3" interfacename="geometry_normal" />
-      <input name="mode" type="string" value="zeltner" />
-    </sheen_bsdf>
-    <layer name="fuzz_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="fuzz_bsdf" />
-      <input name="base" type="BSDF" nodename="coat_layer" />
-    </layer>
-
-    <!-- Emission Layer -->
-    <subtract name="coat_ior_minus_one" type="float">
-      <input name="in1" type="float" interfacename="coat_ior" />
-      <input name="in2" type="float" value="1.0" />
-    </subtract>
-    <add name="coat_ior_plus_one" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="coat_ior" />
-    </add>
-    <divide name="coat_ior_to_F0_sqrt" type="float">
-      <input name="in1" type="float" nodename="coat_ior_minus_one" />
-      <input name="in2" type="float" nodename="coat_ior_plus_one" />
-    </divide>
-    <multiply name="coat_ior_to_F0" type="float">
-      <input name="in1" type="float" nodename="coat_ior_to_F0_sqrt" />
-      <input name="in2" type="float" nodename="coat_ior_to_F0_sqrt" />
-    </multiply>
-    <multiply name="emission_weight" type="color3">
-      <input name="in1" type="color3" interfacename="emission_color" />
-      <input name="in2" type="float" interfacename="emission_luminance" />
-    </multiply>
-    <uniform_edf name="uncoated_emission_edf" type="EDF">
-      <input name="color" type="color3" nodename="emission_weight" />
-    </uniform_edf>
-    <multiply name="coat_tinted_emission_edf" type="EDF">
-      <input name="in1" type="EDF" nodename="uncoated_emission_edf" />
-      <input name="in2" type="color3" interfacename="coat_color" />
-    </multiply>
-    <convert name="one_minus_coat_F0_color" type="color3">
-      <input name="in" type="float" nodename="one_minus_coat_F0" />
-    </convert>
-    <generalized_schlick_edf name="coated_emission_edf" type="EDF">
-      <input name="color0" type="color3" nodename="one_minus_coat_F0_color" />
-      <input name="color90" type="color3" value="0.0, 0.0, 0.0" />
-      <input name="exponent" type="float" value="5.0" />
-      <input name="base" type="EDF" nodename="coat_tinted_emission_edf" />
-    </generalized_schlick_edf>
-    <mix name="emission_edf" type="EDF">
-      <input name="fg" type="EDF" nodename="coated_emission_edf" />
-      <input name="bg" type="EDF" nodename="uncoated_emission_edf" />
-      <input name="mix" type="float" interfacename="coat_weight" />
-    </mix>
-
-    <!-- Surface Construction -->
-    <surface name="shader_constructor" type="surfaceshader">
-      <input name="bsdf" type="BSDF" nodename="fuzz_layer" />
-      <input name="edf" type="EDF" nodename="emission_edf" />
-      <input name="opacity" type="float" interfacename="geometry_opacity" />
-    </surface>
-
-    <!-- Output -->
-    <output name="out" type="surfaceshader" nodename="shader_constructor" />
-
-  </nodegraph>
-
-  <!--
-    OpenPBR Anisotropy node definition
-  -->
-  <nodedef name="ND_open_pbr_anisotropy" node="open_pbr_anisotropy" nodegroup="pbr" doc="Computes anisotropic surface roughness as defined in the OpenPBR specification.">
-    <input name="roughness" type="float" value="0.0" />
-    <input name="anisotropy" type="float" value="0.0" />
-    <output name="out" type="vector2" />
-  </nodedef>
-
-  <!--
-    OpenPBR Anisotropy graph definition
-  -->
-  <nodegraph name="NG_open_pbr_anisotropy" nodedef="ND_open_pbr_anisotropy">
-    <invert name="aniso_invert" type="float">
-      <input name="in" type="float" interfacename="anisotropy" />
-    </invert>
-    <multiply name="aniso_invert_sq" type="float">
-      <input name="in1" type="float" nodename="aniso_invert" />
-      <input name="in2" type="float" nodename="aniso_invert" />
-    </multiply>
-    <add name="denom" type="float">
-      <input name="in1" type="float" nodename="aniso_invert_sq" />
-      <input name="in2" type="float" value="1.0" />
-    </add>
-    <divide name="fraction" type="float">
-      <input name="in1" type="float" value="2.0" />
-      <input name="in2" type="float" nodename="denom" />
-    </divide>
-    <sqrt name="sqrt" type="float">
-      <input name="in" type="float" nodename="fraction" />
-    </sqrt>
-    <multiply name="rough_sq" type="float">
-      <input name="in1" type="float" interfacename="roughness" />
-      <input name="in2" type="float" interfacename="roughness" />
-    </multiply>
-    <multiply name="alpha_x" type="float">
-      <input name="in1" type="float" nodename="rough_sq" />
-      <input name="in2" type="float" nodename="sqrt" />
-    </multiply>
-    <multiply name="alpha_y" type="float">
-      <input name="in1" type="float" nodename="aniso_invert" />
-      <input name="in2" type="float" nodename="alpha_x" />
-    </multiply>
-    <combine2 name="result" type="vector2">
-      <input name="in1" type="float" nodename="alpha_x" />
-      <input name="in2" type="float" nodename="alpha_y" />
-    </combine2>
-    <output name="out" type="vector2" nodename="result" />
-  </nodegraph>
-
-</materialx>
diff --git a/libraries/bxdf/genglsl/standard_surface.mtlx b/libraries/bxdf/genglsl/standard_surface.mtlx
deleted file mode 100644
index bedae8e366..0000000000
--- a/libraries/bxdf/genglsl/standard_surface.mtlx
+++ /dev/null
@@ -1,343 +0,0 @@
-<?xml version="1.0"?>
-<materialx version="1.39">
-  <!-- An optimized graph implementation for hardware shading languages,
-       improving the effectiveness of dynamic branches. -->
-
-  <implementation name="IMPL_standard_surface_surfaceshader_optim" nodedef="ND_standard_surface_surfaceshader" nodegraph="NG_standard_surface_surfaceshader_optim" />
-  <nodegraph name="NG_standard_surface_surfaceshader_optim" target="genglsl">
-
-    <!-- Roughness influence by coat-->
-    <!-- Calculate main specular roughness -->
-    <multiply name="coat_affect_roughness_multiply1" type="float">
-      <input name="in1" type="float" interfacename="coat_affect_roughness" />
-      <input name="in2" type="float" interfacename="coat" />
-    </multiply>
-    <multiply name="coat_affect_roughness_multiply2" type="float">
-      <input name="in1" type="float" nodename="coat_affect_roughness_multiply1" />
-      <input name="in2" type="float" interfacename="coat_roughness" />
-    </multiply>
-    <mix name="coat_affected_roughness" type="float">
-      <input name="fg" type="float" value="1.0" />
-      <input name="bg" type="float" interfacename="specular_roughness" />
-      <input name="mix" type="float" nodename="coat_affect_roughness_multiply2" />
-    </mix>
-    <roughness_anisotropy name="main_roughness" type="vector2">
-      <input name="roughness" type="float" nodename="coat_affected_roughness" />
-      <input name="anisotropy" type="float" interfacename="specular_anisotropy" />
-    </roughness_anisotropy>
-    <!-- Calculate transmission roughness -->
-    <add name="transmission_roughness_add" type="float">
-      <input name="in1" type="float" interfacename="specular_roughness" />
-      <input name="in2" type="float" interfacename="transmission_extra_roughness" />
-    </add>
-    <clamp name="transmission_roughness_clamped" type="float">
-      <input name="in" type="float" nodename="transmission_roughness_add" />
-    </clamp>
-    <mix name="coat_affected_transmission_roughness" type="float">
-      <input name="fg" type="float" value="1.0" />
-      <input name="bg" type="float" nodename="transmission_roughness_clamped" />
-      <input name="mix" type="float" nodename="coat_affect_roughness_multiply2" />
-    </mix>
-    <roughness_anisotropy name="transmission_roughness" type="vector2">
-      <input name="roughness" type="float" nodename="coat_affected_transmission_roughness" />
-      <input name="anisotropy" type="float" interfacename="specular_anisotropy" />
-    </roughness_anisotropy>
-
-    <!-- Tangent rotation -->
-    <multiply name="tangent_rotate_degree" type="float">
-      <input name="in1" type="float" interfacename="specular_rotation" />
-      <input name="in2" type="float" value="360" />
-    </multiply>
-    <rotate3d name="tangent_rotate" type="vector3">
-      <input name="in" type="vector3" interfacename="tangent" />
-      <input name="amount" type="float" nodename="tangent_rotate_degree" />
-      <input name="axis" type="vector3" interfacename="normal" />
-    </rotate3d>
-    <normalize name="tangent_rotate_normalize" type="vector3">
-      <input name="in" type="vector3" nodename="tangent_rotate" />
-    </normalize>
-    <ifgreater name="main_tangent" type="vector3">
-      <input name="value1" type="float" interfacename="specular_anisotropy" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="vector3" nodename="tangent_rotate_normalize" />
-      <input name="in2" type="vector3" interfacename="tangent" />
-    </ifgreater>
-
-    <!-- Coat tangent rotation -->
-    <multiply name="coat_tangent_rotate_degree" type="float">
-      <input name="in1" type="float" interfacename="coat_rotation" />
-      <input name="in2" type="float" value="360" />
-    </multiply>
-    <rotate3d name="coat_tangent_rotate" type="vector3">
-      <input name="in" type="vector3" interfacename="tangent" />
-      <input name="amount" type="float" nodename="coat_tangent_rotate_degree" />
-      <input name="axis" type="vector3" interfacename="coat_normal" />
-    </rotate3d>
-    <normalize name="coat_tangent_rotate_normalize" type="vector3">
-      <input name="in" type="vector3" nodename="coat_tangent_rotate" />
-    </normalize>
-    <ifgreater name="coat_tangent" type="vector3">
-      <input name="value1" type="float" interfacename="coat_anisotropy" />
-      <input name="value2" type="float" value="0.0" />
-      <input name="in1" type="vector3" nodename="coat_tangent_rotate_normalize" />
-      <input name="in2" type="vector3" interfacename="tangent" />
-    </ifgreater>
-
-    <!-- Colors influenced by coat ("coat gamma") -->
-    <clamp name="coat_clamped" type="float">
-      <input name="in" type="float" interfacename="coat" />
-    </clamp>
-    <multiply name="coat_gamma_multiply" type="float">
-      <input name="in1" type="float" nodename="coat_clamped" />
-      <input name="in2" type="float" interfacename="coat_affect_color" />
-    </multiply>
-    <add name="coat_gamma" type="float">
-      <input name="in1" type="float" nodename="coat_gamma_multiply" />
-      <input name="in2" type="float" value="1.0" />
-    </add>
-    <max name="base_color_nonnegative" type="color3">
-      <input name="in1" type="color3" interfacename="base_color" />
-      <input name="in2" type="float" value="0.0" />
-    </max>
-    <power name="coat_affected_diffuse_color" type="color3">
-      <input name="in1" type="color3" nodename="base_color_nonnegative" />
-      <input name="in2" type="float" nodename="coat_gamma" />
-    </power>
-    <max name="subsurface_color_nonnegative" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_color" />
-      <input name="in2" type="float" value="0.0" />
-    </max>
-    <power name="coat_affected_subsurface_color" type="color3">
-      <input name="in1" type="color3" nodename="subsurface_color_nonnegative" />
-      <input name="in2" type="float" nodename="coat_gamma" />
-    </power>
-
-    <!-- Diffuse/Subsurface Layer -->
-    <oren_nayar_diffuse_bsdf name="diffuse_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="base" />
-      <input name="color" type="color3" nodename="coat_affected_diffuse_color" />
-      <input name="roughness" type="float" interfacename="diffuse_roughness" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </oren_nayar_diffuse_bsdf>
-    <translucent_bsdf name="translucent_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="subsurface" />
-      <input name="color" type="color3" nodename="coat_affected_subsurface_color" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </translucent_bsdf>
-    <multiply name="subsurface_radius_scaled" type="color3">
-      <input name="in1" type="color3" interfacename="subsurface_radius" />
-      <input name="in2" type="float" interfacename="subsurface_scale" />
-    </multiply>
-    <subsurface_bsdf name="subsurface_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="subsurface" />
-      <input name="color" type="color3" nodename="coat_affected_subsurface_color" />
-      <input name="radius" type="color3" nodename="subsurface_radius_scaled" />
-      <input name="anisotropy" type="float" interfacename="subsurface_anisotropy" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </subsurface_bsdf>
-    <convert name="subsurface_selector" type="float">
-      <input name="in" type="boolean" interfacename="thin_walled" />
-    </convert>
-    <mix name="selected_subsurface_bsdf" type="BSDF">
-      <input name="fg" type="BSDF" nodename="translucent_bsdf" />
-      <input name="bg" type="BSDF" nodename="subsurface_bsdf" />
-      <input name="mix" type="float" nodename="subsurface_selector" />
-    </mix>
-    <invert name="subsurface_inv" type="float">
-      <input name="in" type="float" interfacename="subsurface" />
-    </invert>
-    <multiply name="diffuse_bsdf_non_subsurface" type="BSDF">
-      <input name="in1" type="BSDF" nodename="diffuse_bsdf" />
-      <input name="in2" type="float" nodename="subsurface_inv" />
-    </multiply>
-    <add name="subsurface_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="selected_subsurface_bsdf" />
-      <input name="in2" type="BSDF" nodename="diffuse_bsdf_non_subsurface" />
-    </add>
-
-    <!-- Sheen Layer -->
-    <sheen_bsdf name="sheen_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="sheen" />
-      <input name="color" type="color3" interfacename="sheen_color" />
-      <input name="roughness" type="float" interfacename="sheen_roughness" />
-      <input name="normal" type="vector3" interfacename="normal" />
-    </sheen_bsdf>
-    <layer name="sheen_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="sheen_bsdf" />
-      <input name="base" type="BSDF" nodename="subsurface_blend" />
-    </layer>
-
-    <!-- Transmission Layer -->
-    <dielectric_bsdf name="transmission_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="transmission" />
-      <input name="tint" type="color3" interfacename="transmission_color" />
-      <input name="ior" type="float" interfacename="specular_IOR" />
-      <input name="roughness" type="vector2" nodename="transmission_roughness" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="main_tangent" />
-      <input name="distribution" type="string" value="ggx" />
-      <input name="scatter_mode" type="string" value="T" />
-    </dielectric_bsdf>
-    <invert name="transmission_inv" type="float">
-      <input name="in" type="float" interfacename="transmission" />
-    </invert>
-    <multiply name="sheen_layer_non_transmission" type="BSDF">
-      <input name="in1" type="BSDF" nodename="sheen_layer" />
-      <input name="in2" type="float" nodename="transmission_inv" />
-    </multiply>
-    <add name="transmission_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="transmission_bsdf" />
-      <input name="in2" type="BSDF" nodename="sheen_layer_non_transmission" />
-    </add>
-
-    <!-- Specular Layer -->
-    <dielectric_bsdf name="specular_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="specular" />
-      <input name="tint" type="color3" interfacename="specular_color" />
-      <input name="ior" type="float" interfacename="specular_IOR" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="main_tangent" />
-      <input name="distribution" type="string" value="ggx" />
-      <input name="scatter_mode" type="string" value="R" />
-      <input name="thinfilm_thickness" type="float" interfacename="thin_film_thickness" />
-      <input name="thinfilm_ior" type="float" interfacename="thin_film_IOR" />
-    </dielectric_bsdf>
-    <layer name="specular_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="specular_bsdf" />
-      <input name="base" type="BSDF" nodename="transmission_blend" />
-    </layer>
-
-    <!-- Metal Layer -->
-    <multiply name="metal_reflectivity" type="color3">
-      <input name="in1" type="color3" interfacename="base_color" />
-      <input name="in2" type="float" interfacename="base" />
-    </multiply>
-    <multiply name="metal_edgecolor" type="color3">
-      <input name="in1" type="color3" interfacename="specular_color" />
-      <input name="in2" type="float" interfacename="specular" />
-    </multiply>
-    <artistic_ior name="artistic_ior" type="multioutput">
-      <input name="reflectivity" type="color3" nodename="metal_reflectivity" />
-      <input name="edge_color" type="color3" nodename="metal_edgecolor" />
-    </artistic_ior>
-    <conductor_bsdf name="metal_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="metalness" />
-      <input name="ior" type="color3" nodename="artistic_ior" output="ior" />
-      <input name="extinction" type="color3" nodename="artistic_ior" output="extinction" />
-      <input name="roughness" type="vector2" nodename="main_roughness" />
-      <input name="normal" type="vector3" interfacename="normal" />
-      <input name="tangent" type="vector3" nodename="main_tangent" />
-      <input name="distribution" type="string" value="ggx" />
-      <input name="thinfilm_thickness" type="float" interfacename="thin_film_thickness" />
-      <input name="thinfilm_ior" type="float" interfacename="thin_film_IOR" />
-    </conductor_bsdf>
-    <invert name="metalness_inv" type="float">
-      <input name="in" type="float" interfacename="metalness" />
-    </invert>
-    <multiply name="specular_layer_non_metal" type="BSDF">
-      <input name="in1" type="BSDF" nodename="specular_layer" />
-      <input name="in2" type="float" nodename="metalness_inv" />
-    </multiply>
-    <add name="metalness_blend" type="BSDF">
-      <input name="in1" type="BSDF" nodename="metal_bsdf" />
-      <input name="in2" type="BSDF" nodename="specular_layer_non_metal" />
-    </add>
-
-    <!-- Coat Layer -->
-    <mix name="coat_attenuation" type="color3">
-      <input name="fg" type="color3" interfacename="coat_color" />
-      <input name="bg" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="mix" type="float" interfacename="coat" />
-    </mix>
-    <multiply name="thin_film_layer_attenuated" type="BSDF">
-      <input name="in1" type="BSDF" nodename="metalness_blend" />
-      <input name="in2" type="color3" nodename="coat_attenuation" />
-    </multiply>
-    <roughness_anisotropy name="coat_roughness_vector" type="vector2">
-      <input name="roughness" type="float" interfacename="coat_roughness" />
-      <input name="anisotropy" type="float" interfacename="coat_anisotropy" />
-    </roughness_anisotropy>
-    <dielectric_bsdf name="coat_bsdf" type="BSDF">
-      <input name="weight" type="float" interfacename="coat" />
-      <input name="tint" type="color3" value="1.0, 1.0, 1.0" />
-      <input name="ior" type="float" interfacename="coat_IOR" />
-      <input name="roughness" type="vector2" nodename="coat_roughness_vector" />
-      <input name="normal" type="vector3" interfacename="coat_normal" />
-      <input name="tangent" type="vector3" nodename="coat_tangent" />
-      <input name="distribution" type="string" value="ggx" />
-      <input name="scatter_mode" type="string" value="R" />
-    </dielectric_bsdf>
-    <layer name="coat_layer" type="BSDF">
-      <input name="top" type="BSDF" nodename="coat_bsdf" />
-      <input name="base" type="BSDF" nodename="thin_film_layer_attenuated" />
-    </layer>
-
-    <!-- Emission Layer -->
-    <subtract name="one_minus_coat_ior" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="coat_IOR" />
-    </subtract>
-    <add name="one_plus_coat_ior" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" interfacename="coat_IOR" />
-    </add>
-    <divide name="coat_ior_to_F0_sqrt" type="float">
-      <input name="in1" type="float" nodename="one_minus_coat_ior" />
-      <input name="in2" type="float" nodename="one_plus_coat_ior" />
-    </divide>
-    <multiply name="coat_ior_to_F0" type="float">
-      <input name="in1" type="float" nodename="coat_ior_to_F0_sqrt" />
-      <input name="in2" type="float" nodename="coat_ior_to_F0_sqrt" />
-    </multiply>
-    <subtract name="one_minus_coat_ior_to_F0" type="float">
-      <input name="in1" type="float" value="1.0" />
-      <input name="in2" type="float" nodename="coat_ior_to_F0" />
-    </subtract>
-    <multiply name="emission_weight" type="color3">
-      <input name="in1" type="color3" interfacename="emission_color" />
-      <input name="in2" type="float" interfacename="emission" />
-    </multiply>
-    <uniform_edf name="emission_edf" type="EDF">
-      <input name="color" type="color3" nodename="emission_weight" />
-    </uniform_edf>
-    <multiply name="coat_tinted_emission_edf" type="EDF">
-      <input name="in1" type="EDF" nodename="emission_edf" />
-      <input name="in2" type="color3" interfacename="coat_color" />
-    </multiply>
-    <convert name="emission_color0" type="color3">
-      <input name="in" type="float" nodename="one_minus_coat_ior_to_F0" />
-    </convert>
-    <generalized_schlick_edf name="coat_emission_edf" type="EDF">
-      <input name="color0" type="color3" nodename="emission_color0" />
-      <input name="color90" type="color3" value="0.0, 0.0, 0.0" />
-      <input name="exponent" type="float" value="5.0" />
-      <input name="base" type="EDF" nodename="coat_tinted_emission_edf" />
-    </generalized_schlick_edf>
-    <mix name="blended_coat_emission_edf" type="EDF">
-      <input name="fg" type="EDF" nodename="coat_emission_edf" />
-      <input name="bg" type="EDF" nodename="emission_edf" />
-      <input name="mix" type="float" interfacename="coat" />
-    </mix>
-
-    <!-- Surface construction with opacity -->
-    <!-- Node <surface> only supports monochromatic opacity so use the luminance of input opacity color -->
-    <luminance name="opacity_luminance" type="color3">
-      <input name="in" type="color3" interfacename="opacity" />
-    </luminance>
-    <extract name="opacity_luminance_float" type="float">
-      <input name="in" type="color3" nodename="opacity_luminance" />
-      <input name="index" type="integer" value="0" />
-    </extract>
-    <surface name="shader_constructor" type="surfaceshader">
-      <input name="bsdf" type="BSDF" nodename="coat_layer" />
-      <input name="edf" type="EDF" nodename="blended_coat_emission_edf" />
-      <input name="opacity" type="float" nodename="opacity_luminance_float" />
-    </surface>
-
-    <!-- Output -->
-    <output name="out" type="surfaceshader" nodename="shader_constructor" />
-
-  </nodegraph>
-
-</materialx>
diff --git a/source/MaterialXGenShader/ShaderGraph.cpp b/source/MaterialXGenShader/ShaderGraph.cpp
index 796e328178..cc6d013970 100644
--- a/source/MaterialXGenShader/ShaderGraph.cpp
+++ b/source/MaterialXGenShader/ShaderGraph.cpp
@@ -1070,23 +1070,29 @@ void ShaderGraph::optimize(GenContext& context)
         _nodeOrder = usedNodesVec;
     }
 
-    // we take a copy of the node list because we might modify it during the optimization
+    // We store node names (not raw pointers) because optimization may call
+    // removeNode(), which deletes nodes via shared_ptr. Raw pointers would dangle.
     if (context.getOptions().optReplaceBsdfMixWithLinearCombination)
     {
-        const vector<ShaderNode*> nodeList = getNodes();
-        for (ShaderNode* node : nodeList)
+        vector<string> mixBsdfNodeNames;
+        for (ShaderNode* node : getNodes())
         {
-            // first check the node is still in the graph, and hasn't been removed by a
-            // prior optimization
-            if (!getNode(node->getName()))
+            if (node->hasClassification(ShaderNode::Classification::MIX_BSDF))
+            {
+                mixBsdfNodeNames.push_back(node->getName());
+            }
+        }
+
+        for (const string& name : mixBsdfNodeNames)
+        {
+            // Look up fresh each iteration - node may have been removed by prior optimization
+            ShaderNode* node = getNode(name);
+            if (!node)
                 continue;
 
-            if (node->hasClassification(ShaderNode::Classification::MIX_BSDF))
+            if (!optimizeMixMixBsdf(node, context))
             {
-                if (!optimizeMixMixBsdf(node, context))
-                {
-                    optimizeMixBsdf(node, context);
-                }
+                optimizeMixBsdf(node, context);
             }
         }
     }