Validators#

Custom USD asset validation rules built on omniverse-asset-validator. This standalone validator runs outside of Kit and is useful for CI/CD pipelines or environments without GPU access.

Prerequisites#

Install uv.

Available Rules#

Rule	Description
`UpAxisZChecker`	Validates that the stage upAxis is `Z`
`AIFMetadataChecker`	Validates AIF metadata requirements (properties sublayer, core/spec attributes)
`AIFHierarchyHasRootChecker`	Validates that the stage has a single root prim, excludes `/Render`
`AIFRootIsXformableChecker`	Validates that the root prim is xformable
`AIFMetersPerUnitChecker`	Validates that metersPerUnit is `1.0` (meters)
`AIFAssetAtOriginChecker`	Validates that the root prim has an identity transform (at origin)
`DefaultPrimChecker`	Validates that the stage has a default prim
`ExtentsChecker`	Validates that boundable prims have correct extent attributes
`AIFNormalsValidChecker`	Validates mesh normals are finite and match interpolation counts
`NormalsExistChecker`	Validates meshes have normals unless subdivision is set
`ValidateTopologyChecker`	Validates mesh topology on all time samples
`NormalsWindingsChecker`	Validates mesh normals are consistent with face windings
`AIFGeomShallBeMeshChecker`	Validates all geometry prims are `UsdGeom.Mesh`

Usage#

# Run all AIF rules on an asset
uv run --directory oav validate --category AIF /path/to/asset.usd

# Run a specific rule
uv run --directory oav validate --rule AIFMetadataChecker /path/to/asset.usd

# Run all rules
uv run --directory oav validate /path/to/asset.usd

# Show help
uv run --directory oav validate --help

Writing Custom Rules#

Implement custom validation rules by extending BaseRuleChecker. Here is a minimal example from oav/aif_validators/up_axis_z.py:

from omni.asset_validator import BaseRuleChecker, register_rule
from pxr import Usd, UsdGeom

@register_rule("AIF")
class UpAxisZChecker(BaseRuleChecker):
    """Validates that stage upAxis is 'Z'."""

    def CheckStage(self, stage: Usd.Stage) -> None:
        up_axis = UsdGeom.GetStageUpAxis(stage)
        if up_axis != UsdGeom.Tokens.z:
            self._AddFailedCheck(
                message=f"Stage has upAxis of '{up_axis}', not 'Z'.", at=stage
            )

Kit Compared to Standalone Validation#

This project offers two validation paths that differ in runtime, rule set, and performance:

	Kit Validation	Omni Asset Validator (OAV)
Runtime	Runs inside a Kit application (USD Composer or headless Kit)	Standalone Python library (`pip`/`uv` installable)
Rule set	Built-in rules from `omni.asset_validator.core` plus C-accelerated rules from `omni.scene.optimizer.validators`	Custom AIF rules in `oav/aif_validators/` registered against the `omniverse-asset-validator` pip package
Performance	Scene Optimizer substitutes C-accelerated implementations for some rules	Pure Python on `usd-core`
GPU required	Yes (Kit requires a GPU)	No
Best for	Interactive use, large assets, production pipelines with Kit available	CI/CD pipelines, lightweight local checks, environments without GPU
CLI command	`aif-pipeline validate`	`uv run --directory oav validate`

The two paths share the same rule authoring API (BaseRuleChecker) - rules written for one are API-compatible with the other. However, they currently run overlapping but separate rule sets: Kit validation does not load the custom AIF rules from oav/, and the standalone OAV CLI does not have access to Scene Optimizer’s C-accelerated rules.