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jstone-lucasfilm merged 5 commits into from
Jan 4, 2026
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Merged

Apply comparenodedefs.py to PBR Nodes #2738

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6ba1df7
Apply comparenodedefs.py to PBR Nodes
jstone-lucasfilm Jan 2, 2026
6834159
Restore default for edf input
jstone-lucasfilm Jan 2, 2026
a7c3993
Fix spacing for displacement
jstone-lucasfilm Jan 2, 2026
c775b51
Group surface and displacement nodes
jstone-lucasfilm Jan 2, 2026
cd737c5
Move displacement back to StandardNodes
jstone-lucasfilm Jan 4, 2026
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3 changes: 2 additions & 1 deletion .github/workflows/main.yml
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Expand Up @@ -228,7 +228,8 @@ jobs:
run: |
python MaterialXTest/main.py
python MaterialXTest/genshader.py
python Scripts/comparenodedefs.py
python Scripts/comparenodedefs.py --spec ../documents/Specification/MaterialX.StandardNodes.md --mtlx ../libraries/stdlib/stdlib_defs.mtlx
python Scripts/comparenodedefs.py --spec ../documents/Specification/MaterialX.PBRSpec.md --mtlx ../libraries/pbrlib/pbrlib_defs.mtlx
python Scripts/creatematerial.py ../resources/Materials/Examples/StandardSurface/chess_set --texturePrefix chessboard --shadingModel standard_surface
python Scripts/creatematerial.py ../resources/Materials/Examples/GltfPbr/boombox --shadingModel gltf_pbr
python Scripts/mxformat.py ../resources/Materials/TestSuite/stdlib/upgrade --yes --upgrade
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52 changes: 32 additions & 20 deletions documents/Specification/MaterialX.PBRSpec.md
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Expand Up @@ -398,28 +398,28 @@ Adds a directionally varying factor to an EDF. Scales the emission distribution
### `absorption_vdf`
Constructs a VDF for pure light absorption.

The `absorption` input represents the absorption rate per distance traveled in the medium, stated in _m<sup>−1</sup>_, with independent control for each color channel.
The `absorption` input represents the absorption rate per distance traveled in the medium, stated in _m<sup>−1</sup>_, with independent control for each wavelength.

|Port |Description |Type |Default |
|------------|------------------------------|-------|-------------|
|`absorption`|Absorption rate for the medium|color3 |0.0, 0.0, 0.0|
|`absorption`|Absorption rate for the medium|vector3|0.0, 0.0, 0.0|
|`out` |Output: the computed VDF |VDF | |

<a id="node-anisotropic-vdf"> </a>

### `anisotropic_vdf`
Constructs a VDF scattering light for a participating medium, based on the Henyey-Greenstein phase function[^Pharr2023]. Forward, backward and uniform scattering is supported and controlled by the anisotropy input.

The `absorption` input represents the absorption rate per distance traveled in the medium, stated in _m<sup>−1</sup>_, with independent control for each color channel.
The `absorption` input represents the absorption rate per distance traveled in the medium, stated in _m<sup>−1</sup>_, with independent control for each wavelength.

The `anisotropy` input controls the scattering direction: negative values produce backwards scattering, positive values produce forward scattering, and 0.0 produces uniform scattering. Both absorption and scattering rates are specified per color channel/wavelength.
The `anisotropy` input controls the scattering direction: negative values produce backwards scattering, positive values produce forward scattering, and 0.0 produces uniform scattering. Both absorption and scattering rates are specified per wavelength.

|Port |Description |Type |Default |Accepted Values|
|------------|------------------------------------------|------|-------------|---------------|
|`absorption`|Absorption rate for the medium |color3|0.0, 0.0, 0.0| |
|`scattering`|Scattering rate for the medium |color3|0.0, 0.0, 0.0| |
|`anisotropy`|Anisotropy factor for scattering direction|float |0.0 |[-1, 1] |
|`out` |Output: the computed VDF |VDF | | |
|Port |Description |Type |Default |Accepted Values|
|------------|------------------------------------------|-------|-------------|---------------|
|`absorption`|Absorption rate for the medium |vector3|0.0, 0.0, 0.0| |
|`scattering`|Scattering rate for the medium |vector3|0.0, 0.0, 0.0| |
|`anisotropy`|Anisotropy factor for scattering direction|float |0.0 |[-1, 1] |
|`out` |Output: the computed VDF |VDF | | |


## PBR Shader Nodes
Expand All @@ -439,6 +439,19 @@ If the `edf` input is left unconnected, no emission will occur from the surface.
|`thin_walled`|Set to true to make the surface thin-walled |boolean |false |
|`out` |Output: the computed surface shader |surfaceshader| |

<a id="node-displacement"> </a>

### `displacement`
Constructs a displacement shader describing geometric modification to surfaces.

The scalar signature displaces along the surface normal direction, while the vector signature allows displacement in tangent/normal space using (dPdu, dPdv, N) coordinates.

|Port |Description |Type |Default |
|--------------|----------------------------------------|------------------|--------|
|`displacement`|Displacement amount or direction |float, vector3 |__zero__|
|`scale` |Scale factor for the displacement |float |1.0 |
|`out` |Output: the computed displacement shader|displacementshader| |

<a id="node-volume"> </a>

### `volume`
Expand All @@ -457,15 +470,14 @@ If the `edf` input is left unconnected, no emission will occur from the medium.
### `light`
Constructs a light shader describing an explicit light source. The light shader will emit light according to the connected EDF. If the shader is attached to geometry both sides will be considered for light emission and the EDF controls if light is emitted from both sides or not.

|Port |Description |Type |Default |
|-----------|---------------------------------------------------|------------|-------------|
|`edf` |Emission distribution function for the light source|EDF |__zero__ |
|`intensity`|Intensity multiplier for the EDF's emittance |color3 |1.0, 1.0, 1.0|
|`exposure` |Exposure control for the EDF's emittance |float |0.0 |
|`out` |Output: the computed light shader |lightshader | |

Note that the standard library includes definitions for [**`displacement`**](./MaterialX.Specification.md#node-displacement) and [**`surface_unlit`**](./MaterialX.Specification.md#node-surfaceunlit) shader nodes.
|Port |Description |Type |Default |
|-----------|---------------------------------------------------|------------|--------|
|`edf` |Emission distribution function for the light source|EDF |__zero__|
|`intensity`|Intensity multiplier for the EDF's emittance |float |1.0 |
|`exposure` |Exposure control for the EDF's emittance |float |0.0 |
|`out` |Output: the computed light shader |lightshader | |

Note that the standard library includes a definition for the [**`surface_unlit`**](./MaterialX.StandardNodes.md#node-surfaceunlit) shader node.


## Utility Nodes
Expand Down Expand Up @@ -595,7 +607,7 @@ Converts the hair melanin parameterization to absorption coefficient based on pi
|`melanin_redness` |Amount of redness affected to the output |float |0.5 |[0, 1] |
|`eumelanin_color` |Eumelanin color |color3 |0.657704, 0.498077, 0.254107| |
|`pheomelanin_color` |Pheomelanin color |color3 |0.829444, 0.67032, 0.349938 | |
|`out` |Output: the computed absorption coefficient |vector3| | |
|`absorption` |Output: the computed absorption coefficient |vector3| | |

<a id="node-chiang-hair-absorption-from-color"> </a>

Expand All @@ -606,7 +618,7 @@ Converts the hair scattering color to absorption coefficient using the mapping m
|---------------------|------------------------------------------------|-------|-------------|---------------|
|`color` |Scattering color |color3 |1.0, 1.0, 1.0| |
|`azimuthal_roughness`|Azimuthal roughness |float |0.2 |[0, 1] |
|`out` |Output: the computed absorption coefficient |vector3| | |
|`absorption` |Output: the computed absorption coefficient |vector3| | |

<br>

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17 changes: 0 additions & 17 deletions documents/Specification/MaterialX.StandardNodes.md
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Expand Up @@ -2322,23 +2322,6 @@ An unlit surface shader node, representing a surface that can emit and transmit
|`opacity` |Surface cutout opacity |float |1.0 |
|`out` |Output: unlit surface shader closure |surfaceshader| |

<a id="node-displacement"> </a>

### `displacement`
Constructs a displacement shader describing geometric modification to surfaces.

|Port |Description |Type |Default|
|--------------|------------------------------------------------------------|------------------|-------|
|`displacement`|Scalar along the surface normal direction for each position.|float |0.0 |
|`scale` |Scale factor for the displacement vector. |float |1.0 |
|`out` |Output: displacement shader closure |displacementshader| |

|Port |Description |Type |Default |
|--------------|------------------------------------------------------------------------------|------------------|-------------|
|`displacement`|Vector displacement in (dPdu, dPdv, N) tangent/normal space for each position.|vector3 |0.0, 0.0, 0.0|
|`scale` |Scale factor for the displacement vector. |float |1.0 |
|`out` |Output: displacement shader closure |displacementshader| |

<a id="node-mix-shader"> </a>

### `mix`
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17 changes: 12 additions & 5 deletions python/Scripts/comparenodedefs.py
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Expand Up @@ -62,7 +62,12 @@ def buildTypeGroupVariables(typeGroups):
def parseSpecTypes(typeStr):
'''
Parse a specification type string into (types, typeRef).
Handles "Same as X" and "Same as X or Y" patterns.

Supported patterns:
- Simple types: "float", "color3"
- Comma-separated: "float, color3"
- Union with "or": "BSDF or VDF", "BSDF, EDF, or VDF"
- Type references: "Same as bg", "Same as in1 or float"
'''
if typeStr is None or not typeStr.strip():
return set(), None
Expand All @@ -79,12 +84,14 @@ def parseSpecTypes(typeStr):
extraSet, _ = parseSpecTypes(extraTypes)
return extraSet, refPort

# Normalize "or" to comma: "X or Y" -> "X, Y", "X, Y, or Z" -> "X, Y, Z"
normalized = re.sub(r',?\s+or\s+', ', ', typeStr)

result = set()
for t in typeStr.split(','):
for t in normalized.split(','):
t = t.strip()
if not t:
continue
result.add(t)
if t:
result.add(t)

return result, None

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