# Usd Inspect And Provenance

> Inspect a Blender-exported or supplied USD stage for composition, transforms, units, materials, cameras, render products, semantics, and physics while retaining source-to-derived provenance. Use before OVRTX/OVPhysX handoff, when a render looks wrong, or when a flattened package must be audited without mutating the original.

- Skill: `nvidia-omniverse/usd-inspect-and-provenance` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add nvidia-omniverse/usd-inspect-and-provenance`
- Raw SKILL.md: https://api.skillmd.com/api/skills/nvidia-omniverse/usd-inspect-and-provenance/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: Apache-2.0
- Author: NVIDIA-Omniverse (https://skillmd.com/u/nvidia-omniverse)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/nvidia-omniverse/usd-inspect-and-provenance

---

# USD inspection and provenance

Inspection is read-only. Use a copied package and write reports under a
caller-selected cache directory. The OVRTX/OVPhysX add-on and runtime are
installed dependencies; this skill uses documented Blender/USD tools and their
supported UI/CLI entry points.

## When to Use

Use this skill when inspect a Blender-exported or supplied USD stage for composition, transforms, units, materials, cameras, render products, semantics, and physics while retaining source-to-derived provenance. Use before OVRTX/OVPhysX handoff, when a render looks wrong, or when a flattened package must be audited without mutating the original.

## Freeze identity

1. Hash every supplied `.blend`, `.usd`, `.usda`, `.usdc`, `.usdz`, texture,
   sidecar, and script before inspection. Record absolute paths only in a local
   report; use relative paths in shareable manifests.
2. Record Blender, add-on, USD utility/DCC, runtime, platform, camera, frame,
   and export options. Name the stage under test (`source`, `localized`, or
   `flattened`) and never overwrite a source file.
3. If the stage was generated by the add-on, retain its generation metadata and
   Blender-object-to-USD-prim mapping. A successful render does not prove the
   stage is current or that bindings are correct.

## Instructions

Run `scripts/inspect_usd.py` through Blender's bundled Python when standalone
`pxr` is unavailable. It emits a read-only `usd_stage_inspection.v1` result and
checks composition dependencies, stage metadata, prim identity, finite
transforms, and mesh topology. For example:

```text
blender --background --python scripts/inspect_usd.py -- \
  --stage /absolute/caller-owned/scene.usdc --require-resolved
```

Use `usdcat`, `usdchecker`, a DCC inspector, or the add-on's documented
validation action for additional schema-specific checks. Check:

- layer stack, sublayers, references, payloads, clips, variants, relocates,
  asset paths, and unresolved external files;
- default prim, stable absolute prim paths, active/inactive and visibility
  state, instance/prototype relationships, and duplicate identities;
- `upAxis`, `metersPerUnit`, time codes, frame rate, authored samples, reset
  stack, finite transforms, and representative world-space bounds;
- mesh topology/points/indices, normals, UV primvars and interpolation;
- material bindings/GeomSubsets, texture paths and color spaces, OpenPBR or
  preview-surface networks, lights, camera projection/intrinsics/DOF, and render
  product/output-variable children;
- `UsdPhysics`, collider, mass/inertia, semantic/instance/ID schemas, and
  custom properties when the handoff claims them.

Inspect both authored and evaluated/exported geometry where possible. Missing
evaluated modifiers or a stale generated overlay are stage failures, not merely
look-dev differences.

## Provenance and closure

Build a dependency table with each layer/asset path, resolved copied path,
kind, SHA-256, and status (`present`, `missing`, `external`, `unresolved`).
Compare source and derived stage identity and record every operation (export,
localize, flatten, path rewrite, metadata policy). Preserve both localized and
flattened variants when flattening changes opinions. Do not silently rotate or
rescale geometry because metadata appears surprising; compare representative
transforms first and report any corrective policy explicitly.

## Acceptance

Pass requires all required dependencies resolved, no non-finite transform or
identity errors, expected bindings/products present, and unchanged source
hashes. `blocked` means an inspector, optional USD schema, add-on export, or
runtime capability is unavailable; report the exact capability and continue
only with checks that remain valid. A preview rendered by Blender is not proof
of OVRTX ownership; label render class explicitly.
Return the failed checks and relevant stage/dependency paths. Create a full JSON
inventory only for batch or reproducible handoff. Keep absolute paths and raw
diagnostics local and sanitize anything shared.