MAYA-133932 - Implement OpenPBR import/export #3990
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Add support for backported OpenPBR from MaterialX Add unit test.
| @@ -715,6 +715,26 @@ class UseRegistryShadingModeImporter | |||
| } | |||
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| if (!mayaAttr.isNull()) { | |||
| // Connecting the R component of a color to a color should be possible. Check | |||
| // if there is a compatible parent in case of type mismatch. | |||
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My test case has a few monochrome textures connected to float inputs. Added support for that.
| @@ -37,6 +37,17 @@ target_sources(${PROJECT_NAME} | |||
| ) | |||
| endif() | |||
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| if(USD_HAS_BACKPORTED_MX39_OPENPBR) | |||
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The backported OpenPBR code requires injecting Maya lighting code at the exact right moment. This is done by creating a special closure node to handle to handle the two MaterialX nodes that require updated lighting.
| @@ -0,0 +1,112 @@ | |||
| #ifdef MAYA_MX39_USING_ENVIRONMENT_FIS | |||
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Same code as found in the regular Maya lighting files, but adapted to use Mx39FresnelData and mx39compute_fresnel.
| @@ -335,21 +335,27 @@ struct _MaterialXData | |||
| { | |||
| _MaterialXData() | |||
| { | |||
| _mtlxSearchPath = HdMtlxSearchPaths(); | |||
| try { | |||
| _mtlxSearchPath = HdMtlxSearchPaths(); | |||
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Any error in this code path will throw a C++ exception that will completely break the Maya viewport. Making sure we catch any issue here.
| PXR_NAMESPACE_OPEN_SCOPE | ||
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| /// Shader reader for importing UsdPreviewSurface to Maya's openPBRShader material nodes | ||
| class PxrUsdTranslators_OpenPBRSurfaceReader : public PxrUsdTranslators_MaterialReader |
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There is also identical code to StandardSurface here, but since there was a lot less code, I did not extract a translation table reader. I suspect we would have a lot of similarities in the other surface readers as well.
| const auto coatDarkening | ||
| = _GetMayaAttributeValue<float>(depNodeFn, TrMayaOpenPBRTokens->coatDarkening); | ||
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| // Diffuse: Converting from OpenPBR to StandardSurface requires a bit of math to compute coat |
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Very differenct from StandardSurface here. Code was found in the MaterialX converter networks that remap OpenPBR surface to Standard surface, chained into the Standard surface to UsdPreviewSurface network.
There are a few tweaks here that should be backported to usdStandardSurfaceWriter.cpp:
- How coat affects emissionColor
- How subsurface affects diffuseColor
| @@ -184,7 +184,7 @@ void PxrUsdTranslators_StandardSurfaceWriter::Write(const UsdTimeCode& usdTime) | |||
| shaderSchema, | |||
| PxrMayaUsdPreviewSurfaceTokens->NormalAttrName, | |||
| usdTime, | |||
| /* ignoreIfUnauthored = */ false, | |||
| /* ignoreIfUnauthored = */ true, | |||
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Found while debugging. Do not author an empty normals input if we are not connecting anything to it.
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As good as it gets. Issues with 2nd row 2nd column is known. The OpenGL shader should divide the emissionLuminance by 1000 to get reasonable colors along the range. Same issue with 2nd row last square, which is also emission based.
Issue in 2nd row 3rd square is also known. Exporting normal maps is not yet fully supported.
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Here we are exporting to UsdPreviewSurface, so the roundtrip will lose information, as seen in rows 1 versus 3 and 4 versus 6.
| optionMenuGrp -l `getMayaUsdString("kImportMaterialConvLbl")` -cw 1 $cw1 -ann `getMayaUsdString("kImportMaterialConvAnn")` mayaUsdTranslator_MaterialsConversionMenu; | ||
| menuItem -l `getMayaUsdString("kImportMaterialConvNoneLbl")` -ann "none"; | ||
| if ((int)$apiStringFull >= 20250300) { |
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I guess this is equivalent to the cmake check for OpenPBR
JGamache-autodesk
added
the
ready-for-merge
Add support for backported OpenPBR from MaterialX
Add unit test.