simready-validate silently produces no verdict for .usdz and .usdc assets (extension gate in validate_asset)

[NV-JBapst]

Summary

simready-validate cannot validate .usdz or .usdc assets. It does not report an error — it prints the asset header with no verdict at all and exits 1.

$ simready-validate --rules-path nv_core/sr_specs/docs/capabilities \
    --features-path nv_core/sr_specs/docs/features \
    --profiles-path nv_core/sr_specs/docs/profiles \
    --profile Prop-Robotics-Isaac --version 1.0.0 \
    0SDU0DKMY8.usdz

Asset: 0SDU0DKMY8.usdz
$ echo $?
1

Compare a .usd asset, which prints a verdict line:

Asset: sample_content/.../sm_obs_workbench_tool_a01_01.usd
  [FAILED] Prop-Robotics-Isaac v1.0.0
           FET005_BASE_NEUTRAL: failing requirements: ['com.nvidia.simready.GSP.001']

Because the exit code is 1 and the [PASSED]/[FAILED] line is simply absent, this is indistinguishable from a genuine validation failure. A user batch-validating a directory of .usdz assets gets a non-zero exit and an empty report, with nothing indicating the assets were never opened.

Cause

simready/validate/api.py, in validate_asset():

suffix = asset_path_p.suffix.lower()
if suffix not in [".usd", ".usda"]:
    return None

None is returned with no log line. None is also the return value for "file not found", "profile not registered" and "unexpected exception", so the caller cannot tell these apart.

This excludes two standard USD formats:

• .usdz — the packaged distribution format
• .usdc — the binary crate format

Both open fine with Usd.Stage.Open, and both validate correctly through the public validate_stage() API. Only the extension gate in validate_asset() blocks them:

>>> sv.validate_asset(sv.AssetValidationConfig(asset_path="0SDU0DKMY8.usdz",
...                   profile_id="Prop-Robotics-Isaac", profile_version="1.0.0"))
None
>>> sv.validate_asset(sv.AssetValidationConfig(asset_path="probe.usdc", ...))
None
>>> sv.validate_stage(Usd.Stage.Open("0SDU0DKMY8.usdz"), "Prop-Robotics-Isaac", "1.0.0")
AssetValidationResult(...)   # works

The docstring does list "The file extension is not .usd or .usda" as a None condition, so the gate looks deliberate — but it conflicts with the spec this repository publishes.

Why this looks like a bug rather than a policy

• The spec has a requirement specifically about USDZ assets: AA.OV.001 (ov-usdz-udim-limitation), "Texture UDIMs are not supported in USDZ files in NVIDIA Omniverse". A requirement that only applies to .usdz can never be evaluated, because no .usdz asset can reach the validator through the CLI.
• NVIDIA distributes SimReady prop assets as .usdz. We validated 100 of them; every one had to be routed around the CLI via validate_stage().
• .usdc is a core OpenUSD format with no packaging semantics at all — there is no obvious rationale for excluding it.

Suggested fix

Accept every format the USD runtime can open, and make the remaining None cases observable:

suffix = asset_path_p.suffix.lower()
if suffix not in (".usd", ".usda", ".usdc", ".usdz"):
    logger.warning("Unsupported file extension %r for %s; skipping.", suffix, asset_path_p)
    return None

A logger.warning on each early return would separately fix the silent-None ambiguity, which is the part that makes this expensive to diagnose.

Note that write_metadata=True cannot work for .usdz (the package is not writable in place), so that combination should report a clear error rather than fail quietly.

Environment

• simready-validate 2026.6.4
• usd-validation-nvidia 1.20.0
• Python 3.12, Windows 11

Related

Filed separately from #24, which fixes an ISA.001 checker bug that also broke .usdz assets. That one lives in this repository; this one is in the simready-validate package, so it needs a different fix. Together they were why 100 correctly-authored .usdz assets could not be validated: the CLI never opened them, and the checker would have failed them if it had.

I'm happy to open a PR for this if the simready-validate source is accessible somewhere I can contribute to — I could not find a public repository for the package.

[NV-JBapst]

The same gap blocks simready-benchmark, and the runtime stamp makes it a hard wall

Following up after standing up the runtime benchmark against Isaac Sim 6.0.1. The .usdz gap is not limited to validate_asset() — packaged assets cannot complete the documented validate → benchmark workflow at any point.

1. simready-benchmark rejects .usdz outright

simready-benchmark 2026.6.5:

$ simready-benchmark --plan-only --assets 0SDU0DKMY8.usdz
{"type": "cli_error", "error": "filter_failed",
 "message": "ExplicitListDiscovery: invalid --assets entries — wrong extension (expected .usd/.usda/.usdc): ...0SDU0DKMY8.usdz"}

This one is at least explicit rather than silent, which is an improvement on validate_asset(). But note the two tools disagree about which extensions they accept:

	.usd	.usda	.usdc	.usdz
simready-validate (validate_asset)	✅	✅	❌ silent None	❌ silent None
simready-benchmark (ExplicitListDiscovery)	✅	✅	✅	❌ explicit error

.usdc is accepted by one and silently dropped by the other. Whatever the intended policy is, it would help for both entry points to share it.

2. The blocker is not just the extension gate — it is the stamp

simready-benchmark selects tests from the validation stamp in the asset's customLayerData, not from the asset's contents. An unstamped asset plans zero runs:

"code": "empty_plan", "message": "Plan generated 0 runs from 1 asset(s) ...
 none of the 1 asset(s) match a profile -- they are reported as NOT TESTED.
 Verify each asset is stamped with a profile that exists in profiles.toml."

So benchmarking a .usdz requires stamping it first — and a .usdz cannot be stamped in place:

>>> sv.validate_stage(stage, "Prop-Robotics-Isaac", "1.0.0", write_metadata=True)
pxr.Tf.ErrorException: Error in SdfLayer::_CheckFormatWritability ... 'Cannot save ...'

That is correct USD behaviour — a .usdz package is not writable in place — but it means the extension gate is not the only thing standing in the way. Even if --assets accepted .usdz, the stamp step would still fail.

3. None of this is a USD limitation

The runtime handles .usdz perfectly well. Only the entry points refuse it:

>>> stage = Usd.Stage.Open("0SDU0DKMY8.usdz")   # works
>>> sv.validate_stage(stage, "Prop-Robotics-Isaac", "1.0.0")
AssetValidationResult(...)                       # works, real per-feature results

We validated 100 packaged SimReady .usdz props this way, bypassing the CLI entirely.

Why this matters

.usdz is how SimReady prop content is actually distributed, and this repository carries a requirement (AA.OV.001, ov-usdz-udim-limitation) that applies only to USDZ files — a rule that can never be exercised through the shipped tooling.

Suggested shape of a fix

• Accept .usdz (and .usdc) wherever a stage is only read — validate_asset(), --assets discovery.
• Treat stamping as the genuinely unsupported operation for packaged assets, and fail it with a clear message rather than having it surface as an extension error three layers up. A sidecar (validation.json is already written next to results) would be one way to carry the receipt for packaged assets.
• Align the accepted-extension list between the validator and the benchmark.

Environment: simready-validate 2026.6.4, simready-benchmark 2026.6.5, usd-validation-nvidia 1.20.0, Isaac Sim 6.0.1, Python 3.12, Windows 11.