HYDRA-2168 : Generic translation of custom Maya plugin nodes to Hydra by lanierd-adsk · Pull Request #400 · Autodesk/maya-hydra

lanierd-adsk · 2026-04-02T13:05:56Z

Summary
Adds a generic fallback adapter (MayaHydraGenericDagAdapter) that automatically translates any unrecognized Maya plugin DAG node to Hydra as a mayaCustomDagNode prim, without maya-hydra needing knowledge of specific plugin node types. Maya built-in nodes are always skipped. Exposes plugin node data via a custom mayaNode data source containing the Maya type name (mayaTypeName) and a dictionary of non-default attribute values (mayaAttributes), with per-attribute dirty locators (mayaNode.mayaAttributes.) for efficient change tracking. Provides an example scene index plugin demonstrating how a render delegate (using Arnold's aiPhotometricLight as an illustration) would consume mayaCustomDagNode prims and re-type/map them to standard Hydra prim types — with zero dependency on maya-hydra headers.

Summary Adds a generic fallback adapter (MayaHydraGenericDagAdapter) that automatically translates any unrecognized Maya plugin DAG node to Hydra as a mayaCustomDagNode prim, without maya-hydra needing knowledge of specific plugin node types. Maya built-in nodes are always skipped. Exposes plugin node data via a custom mayaNode data source containing the Maya type name (mayaTypeName) and a dictionary of non-default attribute values (mayaAttributes), with per-attribute dirty locators (mayaNode.mayaAttributes.<attrName>) for efficient change tracking. Provides an example scene index plugin demonstrating how a render delegate (using Arnold's aiPhotometricLight as an illustration) would consume mayaCustomDagNode prims and re-type/map them to standard Hydra prim types — with zero dependency on maya-hydra headers.

Copilot

Pull request overview

Adds a generic fallback path in maya-hydra to translate previously-unhandled plugin-defined Maya DAG nodes into Hydra, exposing their type name + non-default attributes via a dedicated data source, along with an example renderer-side scene index that can re-type/map those prims (illustrated with Arnold’s aiPhotometricLight).

Changes:

Introduce MayaHydraGenericDagAdapter to emit mayaCustomDagNode prims for plugin-registered DAG nodes lacking a dedicated adapter.
Add mayaNode container data source (mayaTypeName, mayaAttributes) and mixed-utils support for extracting non-default plugin-specific attributes.
Add an Arnold-focused example scene index plugin + new Python/GTest coverage validating prim typing, attribute filtering, and dirty locators.

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
test/lib/mayaUsd/render/mayaToHydra/cpp/testGenericDagNodeTranslation.py	Sets up `aiPhotometricLight` nodes in Maya and dispatches to C++ verification.
test/lib/mayaUsd/render/mayaToHydra/cpp/testGenericDagNodeTranslation.cpp	GTest coverage for prim type, data source contents, default filtering, and dirty locators.
test/lib/mayaUsd/render/mayaToHydra/cpp/CMakeLists.txt	Adds new C++ test target source.
test/lib/mayaUsd/render/mayaToHydra/CMakeLists.txt	Registers the new interactive Python test script.
lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.h	Declares generic adapter creation + storage in the scene index.
lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.cpp	Wires generic adapter creation into DAG insertion and pending updates.
lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraGenericNodeDataSource.h	Declares `mayaNode` container data source for generic plugin nodes.
lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraGenericNodeDataSource.cpp	Implements `mayaTypeName`/`mayaAttributes` data source accessors.
lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraDataSource.cpp	Exposes `mayaNode` (and xform/visibility/purpose) for `mayaCustomDagNode` prims.
lib/mayaHydra/hydraExtensions/sceneIndex/CMakeLists.txt	Builds/installs the new generic node data source.
lib/mayaHydra/hydraExtensions/plugInfo.json	Registers the new adapter type for plugin discovery/metadata.
lib/mayaHydra/hydraExtensions/mixedUtils.h	Declares `GetNonDefaultMayaAttributesFromNode()` helper API.
lib/mayaHydra/hydraExtensions/mixedUtils.cpp	Implements non-default attribute extraction with base-class attribute filtering.
lib/mayaHydra/hydraExtensions/adapters/tokens.h	Adds convention tokens (`mayaCustomDagNode`, `mayaNode`, etc.).
lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.h	Declares the generic fallback DAG adapter contract.
lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp	Implements the adapter + per-attribute dirtying callback.
lib/mayaHydra/hydraExtensions/adapters/CMakeLists.txt	Adds the new adapter to the build.
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/plugInfo.json	Example HdSceneIndexPlugin registration (loads with Arnold).
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndexPlugin.h	Declares example scene index plugin wrapper.
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndexPlugin.cpp	Registers example plugin via `HdSceneIndexPluginRegistry`.
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.h	Declares filtering scene index that re-types/maps generic prims.
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp	Implements example translation of `aiPhotometricLight` to `sphereLight`.
lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/CMakeLists.txt	Build/install rules for the example plugin library.
doc/genericPluginNodeTranslation.md	Documents the conventions, data sources, locators, and the example flow.

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Copilot · 2026-04-02T13:12:49Z

lib/mayaHydra/hydraExtensions/mixedUtils.cpp

+static const std::set<std::string>& GetBaseClassAttrNames()
+{
+    static std::set<std::string> names;
+    static bool initialized = false;
+    if (!initialized) {
+        const char* baseTypes[] = { "locator" };
+        for (const char* typeName : baseTypes) {


GetBaseClassAttrNames() uses a manual lazy-init (static bool initialized) to populate a static std::set. This is not thread-safe and can cause a data race if multiple threads call GetNonDefaultMayaAttributesFromNode() concurrently (Hydra scene index evaluation can be multi-threaded, and BUILD_STRICT_MODE enables -Werror but not concurrency checks). Prefer a thread-safe one-time init (e.g., function-local static initialized via a lambda, or std::once_flag + std::call_once) so the set is constructed exactly once without races.

Copilot · 2026-04-02T13:12:50Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp

+void _GenericNodeAttrChanged(
+    MNodeMessage::AttributeMessage msg,
+    MPlug& plug,
+    MPlug& otherPlug,


_GenericNodeAttrChanged has an unused parameter (otherPlug). With the project's -Wall (and -Werror when BUILD_STRICT_MODE is enabled), this can fail the build on some toolchains. Mark it unused (e.g., TF_UNUSED(otherPlug)) or omit the parameter name in the function signature.

Suggested change

MPlug& otherPlug,

MPlug& /*otherPlug*/,

Copilot · 2026-04-02T13:12:50Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+void HdGenericNodeTranslationSceneIndex::_PrimsAdded(
+    const HdSceneIndexBase& sender,
+    const HdSceneIndexObserver::AddedPrimEntries& entries)
+{


The 'sender' parameter is unused. With the project's -Wall (and -Werror when BUILD_STRICT_MODE is enabled), unused parameters can break strict builds. Consider marking it unused (e.g., TF_UNUSED(sender)) or removing the parameter name in the definition.

Copilot · 2026-04-02T13:12:50Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+void HdGenericNodeTranslationSceneIndex::_PrimsRemoved(
+    const HdSceneIndexBase& sender,
+    const HdSceneIndexObserver::RemovedPrimEntries& entries)
+{


The 'sender' parameter is unused here as well; consider TF_UNUSED(sender) (or omit the name) to avoid -Wall/-Werror unused-parameter failures in strict builds.

Copilot · 2026-04-02T13:12:51Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+void HdGenericNodeTranslationSceneIndex::_PrimsDirtied(
+    const HdSceneIndexBase& sender,
+    const HdSceneIndexObserver::DirtiedPrimEntries& entries)
+{


The 'sender' parameter is unused here as well; consider TF_UNUSED(sender) (or omit the name) to avoid -Wall/-Werror unused-parameter failures in strict builds.

Copilot · 2026-04-02T13:12:51Z

...wportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndexPlugin.cpp

+// string ("Arnold") to the target renderer's registered name (e.g., "Prman",
+// "Prman") and handle the relevant Maya node types in the


Comment typo: the example list repeats "Prman" twice ("e.g., "Prman", "Prman""). Replace with distinct examples or a single entry (e.g., "Prman").

Suggested change

// string ("Arnold") to the target renderer's registered name (e.g., "Prman",

// "Prman") and handle the relevant Maya node types in the

// string ("Arnold") to the target renderer's registered name (e.g., "Prman")

// and handle the relevant Maya node types in the

Copilot · 2026-04-02T13:12:51Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp

+    if (!(msg & MNodeMessage::kAttributeSet)) {
+        return;
+    }
+    if (plug.isChild()) {
+        return;
+    }
+    // Message attributes are connection-only with no data value; skip them.
+    if (plug.attribute().apiType() == MFn::kMessageAttribute) {
+        return;
+    }
+
+    auto* adapter = reinterpret_cast<MayaHydraGenericDagAdapter*>(clientData);
+
+    MFnAttribute attr(plug.attribute());
+    TfToken attrName(attr.name().asChar());
+    HdDataSourceLocator locator(
+        MayaHydraAdapterTokens->mayaNode,
+        MayaHydraAdapterTokens->mayaAttributes,
+        attrName);
+    adapter->GetMayaHydraSceneIndex()->DirtyPrims({{ adapter->GetID(), HdDataSourceLocatorSet(locator) }});


The attribute-changed callback dirties mayaNode.mayaAttributes. for all top-level non-message attributes. However, GetNonDefaultMayaAttributesFromNode() explicitly filters out Maya built-in base-class attributes (visibility, worldPosition, castsShadows, etc.), so changes to those attributes will still emit mayaAttributes dirty locators even though the mayaAttributes dictionary will never include them. Consider filtering these out in the callback as well (e.g., skip attributes that belong to Maya base classes) to avoid noisy/inefficient dirtying and better match the "plugin-specific attributes" intent.

…e value, add fixes from copilot comments from code review

Copilot

Pull request overview

Copilot reviewed 24 out of 24 changed files in this pull request and generated 3 comments.

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Copilot · 2026-04-02T14:12:25Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp

+    }
+
+    MFnAttribute attr(plug.attribute());
+    const char* name = attr.name().asChar();


In _GenericNodeAttrChanged(), const char* name = attr.name().asChar(); stores a pointer into a temporary MString returned by attr.name(). That temporary is destroyed at the end of the statement, so name can be dangling by the time it’s used (e.g., in IsBaseClassAttrName(name) / TfToken attrName(name)). Store the MString in a local variable (or construct TfToken directly from a stable string) before taking asChar().

Suggested change

const char* name = attr.name().asChar();

MString attrNameStr = attr.name();

const char* name = attrNameStr.asChar();

Copilot · 2026-04-02T14:12:26Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp

+
+bool MayaHydraGenericDagAdapter::GetVisible()
+{
+    return GetDagPath().isVisible();


MayaHydraGenericDagAdapter::MarkDirty() bypasses MayaHydraDagAdapter::MarkDirty(), so the base class’s internal visibility cache (_visibilityDirty / _isVisible) is never updated. However, the dirty-plug callbacks use IsVisible(false) to decide whether to invalidate transforms / emit DirtyTransform, so after any visibility change (or if a node starts hidden) those decisions can become permanently stale. Consider either (a) delegating the visibility bookkeeping to the base class (e.g., call MayaHydraDagAdapter::MarkDirty() for DirtyVisibility/DirtyTransform), or (b) keep _isVisible up to date by calling UpdateVisibility() in GetVisible() and/or avoid IsVisible() in these callbacks.

Suggested change

return GetDagPath().isVisible();

// Keep the base-class visibility cache (_isVisible / _visibilityDirty)

// in sync so that IsVisible(false) used by dirty-plug callbacks remains

// accurate even after visibility changes.

UpdateVisibility();

return IsVisible(false);

Copilot · 2026-04-02T14:12:26Z

lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/CMakeLists.txt

+set(TARGET_NAME mayaHydraGenericNodeTranslationSceneIndex)
+
+add_library(${TARGET_NAME} SHARED)
+


This example target won’t be built unless its directory is added from lib/mayaHydra/flowViewportAPIExamples/CMakeLists.txt (currently only adds flowViewportAPILocator/footPrintNode/customShadersNode/simpleHydraGenerativeProceduralPlugin). Add an add_subdirectory(genericNodeTranslationSceneIndex) there (optionally gated by whatever flag controls building examples) so the example is actually compiled/installed.

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Copilot reviewed 25 out of 25 changed files in this pull request and generated 1 comment.

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Copilot · 2026-04-02T15:40:53Z

lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.cpp

+    if (!_genericsToAdd.empty()) {
+        for (const auto& obj : _genericsToAdd) {
+            if (obj.isNull()) {
+                continue;
+            }
+            MDagPath dag;
+            MStatus  status = MDagPath::getAPathTo(obj, dag);
+            if (!status) {
+                continue;
+            }
+            if (!dag.hasFn(MFn::kTransform)) {
+                CreateGenericAdapter(dag);
+            }
+        }


In FlushPendingUpdates(), generic nodes are added via MDagPath::getAPathTo() + CreateGenericAdapter() without the same filtering done in InsertDag() (intermediate objects and instanced paths with instanceNumber > 0). This can cause generic adapters/prims to be created for intermediate objects or for non-zero instances (potential duplicates / inconsistent behavior vs initial population). Consider adding the same checks here (isIntermediateObject, instancing guard) before calling CreateGenericAdapter().

Copilot

Pull request overview

Copilot reviewed 25 out of 25 changed files in this pull request and generated 3 comments.

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Copilot · 2026-04-02T15:56:09Z

lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.cpp

    } else if (useMeshAdapter()) {
        _addedNodes.push_back(obj);
+    } else {
+        _genericsToAdd.push_back(obj);


The comment above this if/else block says that when not using the mesh adapter the callback only cares about lights and cameras, but the new logic now also queues non-light/camera DAG nodes into _genericsToAdd. Please update or relocate the comment so it accurately reflects the current behavior (lights/cameras plus generic plugin DAG nodes when mesh adapter is disabled).

Copilot · 2026-04-02T15:56:10Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+void HdGenericNodeTranslationSceneIndex::_PrimsDirtied(
+    const HdSceneIndexBase& /*sender*/,
+    const HdSceneIndexObserver::DirtiedPrimEntries& entries)
+{
+    if (!_IsObserved()) return;
+    _SendPrimsDirtied(entries);
+}


This filtering scene index re-types mayaCustomDagNode prims (e.g. to sphereLight) and synthesizes new data source keys (UsdLuxTokens->inputs:*), but _PrimsDirtied forwards the upstream dirty locators unchanged. Downstream consumers that rely on locator intersection for the translated schema may not notice changes (e.g. mayaNode.mayaAttributes.intensity doesn’t intersect inputs:intensity). Consider translating/augmenting dirty locators for translated prims (or conservatively dirtying a parent/root locator) so updates propagate correctly after re-typing.

Copilot · 2026-04-02T15:56:10Z

...wportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndexPlugin.cpp

+HdSceneIndexBaseRefPtr
+HdGenericNodeTranslationSceneIndexPlugin::_AppendSceneIndex(
+    const HdSceneIndexBaseRefPtr& inputScene,
+    const HdContainerDataSourceHandle& inputArgs)
+{
+    return HdGenericNodeTranslationSceneIndex::New(inputScene);
+}


_AppendSceneIndex doesn’t use inputArgs. Other scene index plugins in this repo explicitly silence this (e.g. customPrimvarSceneIndexPlugin.cpp uses TF_UNUSED(inputArgs)). Consider adding TF_UNUSED(inputArgs) here as well to avoid unused-parameter warnings in builds that treat warnings as errors.

Copilot

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ppt-adsk

Great work! Just a few minor comments.

ppt-adsk · 2026-04-02T19:32:12Z

test/lib/mayaUsd/render/mayaToHydra/cpp/testGenericDagNodeTranslation.py

+            )
+            shapeDefaults = cmds.ls(shapeDefaults, long=True)[0]
+
+        self.setHdStormRenderer()


Do we need this? Is this not the default? Isn't it irrelevant which is the render delegate?

You're right, I removed this. We just need to be in hydra (not VP2)

ppt-adsk · 2026-04-02T20:12:55Z

doc/genericPluginNodeTranslation.md

+   - Makes no assumption about what the node represents (light, mesh, camera, etc.).
+
+3. **Prim insertion**: The adapter inserts a Hydra prim with type `mayaCustomDagNode` into the scene index. The prim carries these data sources:
+   - `xform` -- standard Hydra transform from the DAG path.


Is this the flattened xform from the complete Dag path?

Yes, I've moddified the doc to specify that.

doc/genericPluginNodeTranslation.md

lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/plugInfo.json

ppt-adsk · 2026-04-02T20:31:01Z

test/lib/mayaUsd/render/mayaToHydra/cpp/testGenericDagNodeTranslation.py

+        cmds.optionVar(stringValue=("mhGenericShape", shape))
+        cmds.optionVar(stringValue=("mhGenericShapeDefaults",
+                                    shapeDefaults))


What are these optionVar's doing? Would they be needed in an actual deployment?

The optionVar calls are a test-only mechanism to pass Maya node paths from the Python test setup to the C++ GTest code. They are not needed in any actual deployment -- they're just a way for the Python side to tell the C++ side "here are the node names I created, so you can look them up in the Hydra scene index."

There's nothing wrong with that, but I believe this requirement is already covered by arguments to the mayaHydraCppTest command, so we don't need to create a new mechanism. See

maya-hydra/test/lib/mayaUsd/render/mayaToHydra/cpp/testPicking.py

Line 103 in 2bcfaff

cmds.mayaHydraCppTest(cubeObjectName, "mesh", f="TestPicking.pickObject")

maya-hydra/test/lib/mayaUsd/render/mayaToHydra/cpp/testPicking.cpp

Line 84 in 2bcfaff

auto [argc, argv] = getTestingArgs();

ppt-adsk · 2026-04-02T20:33:43Z

lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.cpp

+    // Skip plugin nodes that already provide their own Hydra scene index
+    // (e.g. mayaUsdProxyShape contributes USD data through registration.cpp).
+    // Translating them generically would create duplicate prims in the scene.
+    static const char* kSceneIndexProviderTypes[] = { "mayaUsdProxyShape" };


We need to find a way to make this extensible...

I actually removed that hardcoded string and I am using the dataProducer registered in flow viewport API as the exclude list as these are already providing their own hydra translation.
The new code is :
// Skip plugin nodes that already provide their own Hydra data through
// the Flow Viewport data producer API. Their MObjectHandle hash code
// is registered in DataProducersNodeHashCodeToSdfPathRegistry when
// they call addDataProducerSceneIndex() with a dccNode pointer.
MObjectHandle nodeHandle(dagPath.node());
if (!Fvp::DataProducersNodeHashCodeToSdfPathRegistry::Instance()
.GetPath(nodeHandle.hashCode()).IsEmpty()) {
return {};
}

lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraGenericNodeDataSource.h

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.h

ppt-adsk · 2026-04-02T20:42:03Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+    auto getFloat = [&](const char* key, float def) -> float {
+        auto it = mayaAttrs.find(key);
+        if (it != mayaAttrs.end() && it->second.IsHolding<float>())
+            return it->second.UncheckedGet<float>();
+        if (it != mayaAttrs.end() && it->second.IsHolding<double>())
+            return static_cast<float>(it->second.UncheckedGet<double>());
+        return def;
+    };
+    auto getVec3f = [&](const char* key, GfVec3f def) -> GfVec3f {
+        auto it = mayaAttrs.find(key);
+        if (it != mayaAttrs.end() && it->second.IsHolding<GfVec3f>())
+            return it->second.UncheckedGet<GfVec3f>();
+        return def;
+    };
+    auto getString = [&](const char* key, std::string def) -> std::string {
+        auto it = mayaAttrs.find(key);
+        if (it != mayaAttrs.end() && it->second.IsHolding<std::string>())
+            return it->second.UncheckedGet<std::string>();
+        return def;
+    };
+    auto getBool = [&](const char* key, bool def) -> bool {
+        auto it = mayaAttrs.find(key);
+        if (it != mayaAttrs.end() && it->second.IsHolding<bool>())
+            return it->second.UncheckedGet<bool>();
+        return def;
+    };


This could be converted into a template, it seems. Also, why are doubles converted to floats?

The four separate lambdas have been consolidated into a single generic getAttr lambda using auto parameter deduction (C++14) and if constexpr (C++17) for the float specialization. I've added a comment which explains why doubles are narrowed to floats: Maya stores many numeric attributes as doubles internally, but Hydra light schemas expect floats.

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Copilot · 2026-04-09T12:46:00Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.h

+ * See flowViewportAPIExamples/genericNodeTranslationSceneIndex/ for a complete
+ * example that translates aiPhotometricLight to a UsdLux sphereLight for Arnold.


The comment references the example path as flowViewportAPIExamples/genericNodeTranslationSceneIndex/, but the example added in this PR lives under lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/. Updating the path (or making it repository-relative in a consistent way) would avoid confusion for readers trying to locate the example.

Suggested change

* See flowViewportAPIExamples/genericNodeTranslationSceneIndex/ for a complete

* example that translates aiPhotometricLight to a UsdLux sphereLight for Arnold.

* See lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/

* for a complete example that translates aiPhotometricLight to a UsdLux

* sphereLight for Arnold.

lilike-adsk · 2026-04-10T15:26:27Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.h

+ * delegate's scene index to react to specific attribute changes without
+ * recomputing everything.
+ */
+class MayaHydraGenericDagAdapter : public MayaHydraDagAdapter


The MayaHydraGenericDagAdapter is a bit confusing, sounds like similar as MayaHydraDagAdapter, would MayaHydraCustomDagAdapter be better?

lilike-adsk · 2026-04-10T15:32:08Z

...lowViewportAPIExamples/genericNodeTranslationSceneIndex/genericNodeTranslationSceneIndex.cpp

+// The original xform and visibility data sources from maya-hydra are preserved
+// via HdOverlayContainerDataSource.
+HdSceneIndexPrim
+HdGenericNodeTranslationSceneIndex::_TranslatePhotometricLight(


Great to see an example, how the the rendering result looks like with PhotometricLight in HdArnold?

lilike-adsk · 2026-04-10T15:35:37Z

lib/mayaHydra/hydraExtensions/sceneIndex/mayaHydraSceneIndex.cpp

                    _shapeAdapters,
                    _lightAdapters,
                    _cameraAdapters,
                    _materialAdapters);


Should we also add _genericAdapters here when dealing _adaptersToRebuild?

lilike-adsk · 2026-04-10T15:45:45Z

lib/mayaHydra/hydraExtensions/adapters/genericDagAdapter.cpp

+// Maya callback invoked when any attribute on the generic node is modified.
+// Fires a per-attribute dirty locator (mayaNode.mayaAttributes.<attrName>)
+// so downstream scene indices can react to specific attribute changes.
+void _GenericNodeAttrChanged(


Do we have extension/custom attributes on custom node? If yes, how did we handle this case?

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Fix a bug with a dirty transform being sent when updating an attribut…

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Second round of copilot fixes

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Implement suggestions from code review, pass #1

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HYDRA-2168 : Fixes from code review

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lanierd-adsk requested review from Copilot and ppt-adsk April 9, 2026 12:35

Copilot started reviewing on behalf of lanierd-adsk April 9, 2026 12:36 View session

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ppt-adsk previously approved these changes Apr 9, 2026

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lanierd-adsk removed the do-not-merge-yet label Apr 10, 2026

lanierd-adsk requested a review from lilike-adsk April 10, 2026 09:29

lanierd-adsk assigned lanierd-adsk and unassigned lanierd-adsk Apr 10, 2026

Merge branch 'dev' into lanierd/HYDRA-2168

939e93e

lanierd-adsk dismissed ppt-adsk’s stale review via 939e93e April 10, 2026 13:58

lanierd-adsk assigned lanierd-adsk and unassigned lanierd-adsk Apr 10, 2026

lanierd-adsk added the do-not-merge-yet label Apr 10, 2026

lilike-adsk reviewed Apr 10, 2026

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		// string ("Arnold") to the target renderer's registered name (e.g., "Prman",
		// "Prman") and handle the relevant Maya node types in the

	const char* name = attr.name().asChar();
	MString attrNameStr = attr.name();
	const char* name = attrNameStr.asChar();

-    return GetDagPath().isVisible();
+    // Keep the base-class visibility cache (_isVisible / _visibilityDirty)
+    // in sync so that IsVisible(false) used by dirty-plug callbacks remains
+    // accurate even after visibility changes.
+    UpdateVisibility();
+    return IsVisible(false);

		set(TARGET_NAME mayaHydraGenericNodeTranslationSceneIndex)

		add_library(${TARGET_NAME} SHARED)

		* See flowViewportAPIExamples/genericNodeTranslationSceneIndex/ for a complete
		* example that translates aiPhotometricLight to a UsdLux sphereLight for Arnold.

- * See flowViewportAPIExamples/genericNodeTranslationSceneIndex/ for a complete
- * example that translates aiPhotometricLight to a UsdLux sphereLight for Arnold.
+ * See lib/mayaHydra/flowViewportAPIExamples/genericNodeTranslationSceneIndex/
+ * for a complete example that translates aiPhotometricLight to a UsdLux
+ * sphereLight for Arnold.

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