The correct plugin type is an asset resolver plugin . In OpenUSD, asset paths such as @mycompany://path/to/my/resource@ are not interpreted as ordinary strings; they are asset identifiers that must be resolved into concrete resources that USD can consume. NVIDIA’s Learn OpenUSD glossary defines asset resolution as the process of translating an asset path into the actual location of a usable resource and states that USD provides the ArResolver plugin point for custom resolution logic, including external databases, custom storage systems, version-control systems, or studio-specific URI schemes.

Option C is correct because a custom asset resolver is precisely where pipeline-specific resource lookup logic belongs. Option A is incorrect because a custom schema plugin defines prim types, API schemas, and properties, not asset-location behavior. Option B is incorrect because Hydra plugins are concerned with imaging, rendering, and scene-index/render-delegate behavior. Option D is incorrect because custom metadata may store extra data, but it does not implement resolution of asset identifiers. This aligns with Pipeline Development → Asset Resolution, ArResolver, Resource Location, Versioned Assets, and Pipeline Integration .

The slower operations are those that change the composed structure of the stage rather than merely changing resolved property values. NVIDIA’s Learn OpenUSD variant-set guidance separates lightweight and heavyweight variant switches. Lightweight switches include changing attribute values and visibility because they affect value resolution or rendering state without requiring USD to rebuild the composed scene structure. In contrast, heavyweight switches include changing reference paths and changing activation opinions because these alter what content is composed onto the stage.

Option A is correct because changing a reference path swaps which external layer or asset contributes scene description, requiring recomputation of affected composition indexes. Option C is correct because activation controls whether prims are composed at all; changing active state can add or remove composed scenegraph structure. Option B is incorrect because visibility is a rendering/imageability opinion and does not remove prims from composition. Option D is incorrect because ordinary attribute-value changes are typically lightweight value-resolution changes. This aligns with Composition → Variant Sets → Variant Design Considerations, Lightweight Variant Switches, Heavyweight Variant Switches, References, Activation, Visibility, and Attribute Opinions .

The exporter should validate and correct authored extent values on every exported UsdGeomBoundable prim. The extent attribute is the local-space bounding range of the authored geometric primitive, and if it is authored incorrectly, clients that trust the authored extent can display oversized or inaccurate bounds. NVIDIA’s asset-requirements documentation states that “Boundable geometry primitives should have valid extent values,” and its compliance guidance says to author extent for boundable geometry and compute it at time samples where geometry-affecting attributes change. ( docs.omniverse.nvidia.com )

Option B is correct because it preserves the intended best-fit bounds and works consistently for any exported boundable prim. Option A is unreliable as an export strategy: OpenUSD may compute extent through registered compute functions when no extent is authored, but this can be expensive and is not a substitute for correct exported data. The OpenUSD UsdGeomBoundable documentation strongly encourages proper authoring of extent. ( openusd.org ) Option C is incorrect because extentsHint is not the replacement for per-primitive boundable extent. Option D is unrelated to geometric bounds. This aligns with Data Exchange → Validation, Geometry Export, Boundable Extents, and Data Quality .

The correct exporter behavior is to generate sparse overrides that represent only the authored contribution of the current workstream. In OpenUSD data exchange workflows, an exporter should not blindly rewrite the full imported asset when the intent is to preserve collaborative, non- destructive editing. Instead, the exporter should author only the changes required to express the current application’s contribution: modified prims, newly added prims, changed attributes, relationships, metadata, or other authored opinions.

Option A is correct because an over is specifically used to contribute opinions to an existing prim without redefining the entire prim structure. This allows the exported layer to sit above the source asset in a layer stack and override only the relevant data. Option B incorrectly equates sparsity with splitting each prim into separate referenced layers; USD sparsity is achieved by authoring minimal opinions, not by unnecessary layer fragmentation. Option C is incorrect because exporting full definitions for every prim and property would duplicate unchanged data, reduce clarity, and undermine USD’s composition-based collaboration model. This maps to the NVIDIA OpenUSD Development Study Guide topics Data Exchange, especially exporter design, data transformation, sparse authoring, and collaborative layer-based workflows.

Strictly evaluated against the OpenUSD API contract, C is the only fully correct statement as written. SdfChangeBlock groups multiple low-level Sdf edits so that change processing can be delayed and handled efficiently as one batch. The official API documentation states that opening a change block causes Sdf to delay notifications until the outermost block exits; notifications are queued, not permanently muted. Therefore, A is incorrect. The same documentation gives a strong warning that it is not safe to use Usd or other downstream APIs while a change block is open, because those representations may be stale or may hold expired handles to Sdf objects. Therefore, querying mutating prims during the block is unsafe, making C correct.

Option B is incorrect because it explicitly says to use USD APIs inside the block, which the official guidance warns against. Option D is also incorrect because the intended safe authoring pattern is to gather required edits first, then apply them directly through the Sdf API inside the change block. This aligns with Pipeline Development → Efficient Authoring, Sdf Layers, SdfChangeBlock, Change Notification, and Bulk Scene Description Mutation .

For an “export as overrides” workflow, the exporter should generate sparse authored opinions that represent only the modified or added contributions of the current workstream. NVIDIA’s Learn OpenUSD Data Transformation guidance explicitly describes this pattern: third-party developers can use the stage from raw extraction to export data as sparse overrides for multi-workstream workflows. It also explains that if an export represents one workstream within a larger asset structure, it may define new prims, apply overrides on existing prims, or both, and should distill the data down to the workstream’s unique contributions.

Option A is correct because over specs and sparse property opinions preserve USD’s non-destructive composition model. They allow a stronger layer to modify the composed result without duplicating unchanged source data. Option B is incorrect because splitting each prim into separate layers is not required for sparsity and would add unnecessary composition complexity. Option C is incorrect because re-exporting the entire imported asset as full definitions would duplicate unchanged data and obscure the actual edits. This aligns with Data Exchange → Data Transformation, Export Options, Sparse Overrides, Round-Trip Exchange, and Multi-Workstream Workflows .

The correct mechanism is a constant-interpolation primvar . NVIDIA’s Learn OpenUSD glossary defines primvars as primitive variables authored using the primvars: namespace and interpolation metadata such as constant, uniform, vertex, and faceVarying. Primvars are designed to carry geometric or shading-related data in a way that consumers can discover through UsdGeomPrimvarsAPI and UsdGeomPrimvar. ( docs.nvidia.com )

Option C is correct because constant primvars can inherit down the namespace hierarchy. The OpenUSD UsdGeomPrimvar documentation states that constant interpolation primvar values can be inherited by child prims unless those children author their own opinion for the same primvar. ( openusd.org ) This allows primvars:myProperty authored on /ParentXform to be discovered on /ParentXform/ChildMesh without duplicating the property on the mesh.

Option A is incorrect because ordinary custom attributes do not automatically propagate to descendant prims. Option B is incorrect because a relationship targets another object; it does not create inherited property data on that target. This aligns with Data Modeling → Primvars, Constant Interpolation, Namespace Inheritance, and Geometric Property Authoring .