Add expanded assembly subcomponent support for pxrUsdReferenceAssembly

lib/mayaUsd/nodes/proxyShapeBase.h

@@ -264,6 +264,19 @@ class MayaUsdProxyShapeBase
         bool*          drawProxyPurpose,
         bool*          drawGuidePurpose);
 
+    /// Returns true if the Maya DAG path already accounts for the USD root
+    /// prim's world transform. When true, the rendering delegate shouldn't
+    /// multiply by GetLocalToWorldTransform(rootPrim), as that would double the
+    /// transforms already present in the Maya DAG.
+    ///
+    /// Defaults to false, which is correct for proxy shapes that reference a USD
+    /// stage without replicating prim transforms into the Maya DAG hierarchy.
+    /// Override to return true only when your plugin expands assembly/subcomponent
+    /// prims as Maya DAG nodes whose transforms already reflect the root prim
+    /// (e.g., Pixar's scene assembly workflow).
+    MAYAUSD_CORE_PUBLIC
+    virtual bool isRootPrimTransformInDagPath() const { return false; }
+
     MAYAUSD_CORE_PUBLIC
     MStatus
     preEvaluation(const MDGContext& context, const MEvaluationNode& evaluationNode) override;

lib/mayaUsd/render/pxrUsdMayaGL/proxyDrawOverride.cpp

@@ -96,9 +96,8 @@ UsdMayaProxyDrawOverride::transform(const MDagPath& objPath, const MDagPath& cam
         GfMatrix4d rootXform(transform.matrix);
 
         MayaUsdProxyShapeBase* pShape = MayaUsdProxyShapeBase::GetShapeAtDagPath(objPath);
-        if (pShape && pShape->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()) {
-            // If we're not computing the transform of the root of the Usd
-            // scene, apply the usdPrim transform from within the scene
+        if (pShape && pShape->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()
+            && !pShape->isRootPrimTransformInDagPath()) {
             const UsdTimeCode timeCode = pShape->getTime();
             UsdGeomXformCache xformCache(timeCode);
             GfMatrix4d primTransform = xformCache.GetLocalToWorldTransform(pShape->usdPrim());

lib/mayaUsd/render/pxrUsdMayaGL/usdProxyShapeAdapter.cpp

@@ -171,19 +171,17 @@ bool PxrMayaHdUsdProxyShapeAdapter::_Sync(
         _renderTags.push_back(HdRenderTagTokens->guide);
     }
 
-    // Update the root transform used to render by the delagate.
-    // USD considers that the root prim transform is always the Identity matrix so that means
-    // the root transform define the root prim transform. When the real stage root is used to
-    // render this is not a issue because the root transform will be the maya transform.
-    // The problem is when using a primPath as the root prim, we are losing
-    // the prim path world transform. So we need to set the root transform as the world
-    // transform of the prim used for rendering.
+    // Update the root transform used to render by the delegate.
+    // When using a primPath as the root prim, USD treats it as identity, so we
+    // compensate by including its world transform in the root transform — unless
+    // the Maya DAG already accounts for it (isRootPrimTransformInDagPath).
     MStatus       status;
     const MMatrix transform = GetDagPath().inclusiveMatrix(&status);
     if (status == MS::kSuccess) {
         _rootXform = GfMatrix4d(transform.matrix);
 
-        if (usdProxyShape->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()) {
+        if (usdProxyShape->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()
+            && !usdProxyShape->isRootPrimTransformInDagPath()) {
             const UsdTimeCode timeCode = usdProxyShape->getTime();
             UsdGeomXformCache xformCache(timeCode);
             GfMatrix4d        primTransform

lib/mayaUsd/render/vp2RenderDelegate/proxyRenderDelegate.cpp

@@ -841,17 +841,15 @@ void ProxyRenderDelegate::_UpdateSceneDelegate()
         _sceneDelegate->SetTime(timeCode);
     }
 
-    // Update the root transform used to render by the delagate.
-    // USD considers that the root prim transform is always the Identity matrix so that means
-    // the root transform define the root prim transform. When the real stage root is used to
-    // render this is not a issue because the root transform will be the maya transform.
-    // The problem is when using a primPath as the root prim, we are losing
-    // the prim path world transform. So we need to set the root transform as the world
-    // transform of the prim used for rendering.
+    // Update the root transform used to render by the delegate.
+    // When using a primPath as the root prim, USD treats it as identity, so we
+    // compensate by including its world transform in the root transform — unless
+    // the Maya DAG already accounts for it (isRootPrimTransformInDagPath).
     const MMatrix inclusiveMatrix = _proxyShapeData->ProxyDagPath().inclusiveMatrix();
     GfMatrix4d    transform(inclusiveMatrix.matrix);
 
-    if (_proxyShapeData->ProxyShape()->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()) {
+    if (_proxyShapeData->ProxyShape()->usdPrim().GetPath() != SdfPath::AbsoluteRootPath()
+        && !_proxyShapeData->ProxyShape()->isRootPrimTransformInDagPath()) {
         const UsdTimeCode timeCode = _proxyShapeData->ProxyShape()->getTime();
         UsdGeomXformCache xformCache(timeCode);
         GfMatrix4d        m

plugin/pxr/maya/lib/usdMaya/AEpxrUsdProxyShapeTemplate.py

@@ -0,0 +1,199 @@
+#
+# Copyright 2026 Pixar
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from pxr import UsdMaya
+
+from maya import cmds
+from maya import mel
+
+import functools
+
+
+# ========================================================================
+# VARIANT SETS
+# ========================================================================
+
+def _GetVariantSetInfoFromNode(node, variantSetName):
+    '''Returns (override, settable) for the variantSetName on node.'''
+    variantAttrName = 'usdVariantSet_%s' % variantSetName
+    override = ''
+    settable = True
+    if cmds.attributeQuery(variantAttrName, node=node, exists=True):
+        variantSetPlgVal = cmds.getAttr('%s.%s' % (node, variantAttrName))
+        if variantSetPlgVal:
+            override = variantSetPlgVal
+        settable = cmds.getAttr('%s.%s' % (node, variantAttrName), settable=True)
+    return override, settable
+
+
+def _variantSets_changeCommand(unused, omg, node, variantSetName):
+    val = cmds.optionMenuGrp(omg, q=True, value=True)
+
+    AuthorVariantSelectionFromAE(node, variantSetName, val)
+
+    # Update the resolved variant selection label
+    resolvedVariant = ''
+    usdPrim = UsdMaya.GetPrim(node)
+    if usdPrim:
+        variantSet = usdPrim.GetVariantSet(variantSetName)
+        if variantSet:
+            resolvedVariant = variantSet.GetVariantSelection()
+    cmds.optionMenuGrp(omg, edit=True, extraLabel=resolvedVariant)
+
+
+def AuthorVariantSelectionFromAE(node, variantSetName, variantSelection):
+    variantAttr = 'usdVariantSet_%s' % variantSetName
+    if not cmds.attributeQuery(variantAttr, node=node, exists=True):
+        cmds.addAttr(node, ln=variantAttr, dt='string', internalSet=True)
+    cmds.setAttr('%s.%s' % (node, variantAttr), variantSelection, type='string')
+
+
+def variantSets_Replace(nodeAttr, new):
+    origParent = cmds.setParent(q=True)
+
+    frameLayoutName = 'AEpxrUsdProxyShapeTemplate_variantSets_Layout'
+    if new:
+        cmds.frameLayout(frameLayoutName, label='VariantSets', collapse=False)
+    else:
+        cmds.setParent(frameLayoutName)
+
+    # Remove existing children of layout
+    children = cmds.frameLayout(frameLayoutName, q=True, childArray=True)
+    if children:
+        for child in children:
+            cmds.deleteUI(child)
+
+    node = nodeAttr.split('.', 1)[0]
+    usdPrim = UsdMaya.GetPrim(node)
+    if usdPrim:
+        for variantSetName in usdPrim.GetVariantSets().GetNames():
+            usdVariantSet = usdPrim.GetVariantSet(variantSetName)
+            variantResolved = usdVariantSet.GetVariantSelection()
+            variantSetChoices = [''] + usdVariantSet.GetVariantNames()
+            variantOverride, variantSettable = _GetVariantSetInfoFromNode(
+                node, variantSetName)
+
+            omg = cmds.optionMenuGrp(
+                label=variantSetName,
+                enable=variantSettable,
+                extraLabel=variantResolved)
+            for choice in variantSetChoices:
+                cmds.menuItem(label=choice)
+
+            try:
+                cmds.optionMenuGrp(omg, e=True, value=variantOverride)
+            except RuntimeError:
+                cmds.warning('Invalid choice %r for %r'
+                             % (variantOverride, variantSetName))
+
+            cmds.optionMenuGrp(omg, e=True,
+                changeCommand=functools.partial(
+                    _variantSets_changeCommand,
+                    omg=omg, node=node, variantSetName=variantSetName))
+
+    cmds.setParent(origParent)
+
+
+def variantSets_Replace_new(nodeAttr):
+    variantSets_Replace(nodeAttr, new=True)
+
+def variantSets_Replace_replace(nodeAttr):
+    variantSets_Replace(nodeAttr, new=False)
+
+
+# ========================================================================
+# FILE PATH
+# ========================================================================
+
+def filePath_Replace(nodeAttr, new):
+    if new:
+        cmds.setUITemplate('attributeEditorTemplate', pushTemplate=True)
+        cmds.rowLayout(numberOfColumns=3)
+        cmds.text(label='File Path')
+        cmds.textField('pxrUsdProxyShape_usdFilePathField')
+        cmds.symbolButton('pxrUsdProxyShape_usdFileBrowserButton',
+                          image='navButtonBrowse.xpm')
+        cmds.setParent('..')
+        cmds.setUITemplate(popTemplate=True)
+
+    def _showFileBrowser(*args):
+        filePaths = cmds.fileDialog2(
+            caption="Specify USD File",
+            fileFilter="USD Files (*.usd*) (*.usd*);;Alembic Files (*.abc)",
+            fileMode=1)
+        if filePaths:
+            cmds.setAttr(nodeAttr, filePaths[0], type='string')
+    cmds.button('pxrUsdProxyShape_usdFileBrowserButton', edit=True,
+                command=_showFileBrowser)
+
+    cmds.evalDeferred(functools.partial(
+        cmds.connectControl, 'pxrUsdProxyShape_usdFilePathField', nodeAttr))
+
+
+def filePath_Replace_new(nodeAttr):
+    filePath_Replace(nodeAttr, new=True)
+
+def filePath_Replace_replace(nodeAttr):
+    filePath_Replace(nodeAttr, new=False)
+
+
+# ========================================================================
+# EDITOR TEMPLATE
+# ========================================================================
+
+def editorTemplate(nodeName):
+    cmds.editorTemplate(beginScrollLayout=True)
+
+    isSubcomponent = UsdMaya.IsSubcomponentProxy(nodeName)
+
+    cmds.editorTemplate(beginLayout='USD', collapse=False)
+    cmds.editorTemplate(
+        'filePath',
+        callCustom=[filePath_Replace_new, filePath_Replace_replace])
+    cmds.editorTemplate('primPath', addControl=True)
+    cmds.editorTemplate('excludePrimPaths', addControl=True)
+    cmds.editorTemplate('variantKey', addControl=True)
+    cmds.editorTemplate('complexity', addControl=True)
+    cmds.editorTemplate('drawRenderPurpose', addControl=True)
+    cmds.editorTemplate('drawProxyPurpose', addControl=True)
+    cmds.editorTemplate('drawGuidePurpose', addControl=True)
+    cmds.editorTemplate(endLayout=True)
+
+    if isSubcomponent:
+        cmds.editorTemplate(beginLayout='Variant Sets', collapse=False)
+        cmds.editorTemplate(
+            '',
+            callCustom=[variantSets_Replace_new, variantSets_Replace_replace])
+        cmds.editorTemplate(endLayout=True)
+
+    mel.eval('AEsurfaceShapeTemplate "%s"' % nodeName)
+    cmds.editorTemplate(addExtraControls=True)
+
+    cmds.editorTemplate(endScrollLayout=True)
+
+
+# ========================================================================
+# MEL STUBS
+# ========================================================================
+
+def addMelFunctionStubs():
+    '''Create MEL proc that delegates to Python for the AE template.'''
+    mel.eval('''
+global proc AEpxrUsdProxyShapeTemplate( string $nodeName )
+{
+    python("AEpxrUsdProxyShapeTemplate.editorTemplate('"+$nodeName+"')");
+}
+    ''')