Omni Asset Validator (Core)

Validates assets against Omniverse specific rules to ensure they run smoothly across all Omniverse products.

It includes the following components:

  • A rule interface and registration mechanism that can be called from external python modules.

  • An engine that runs the rules on a given Usd.Stage, layer file, or recursively searches an OV folder for layer files.

  • An issue fixing interface for applying automated fixes if/when individual rules provide suggestions.


The IssueFixer API is still a work in-progress. Currently no rules provide the necessary suggestions to fix issues.

Validation Rules by Category

Several categories of validation rules are defined in this core module. These include:

  • The Basic rules from Pixar (e.g. the default usdchecker rules).

  • The ARKit rules from Apple (also available via usdchecker).

  • A few NVIDIA developed rules that we plan to contribute back to the Basic set.

  • Some Omniverse specific rules that apply to all Omniverse apps. These will be available under several Omni: prefixed categories.

Writing your own Rules

Any external client code can define new rules and register them with the system. Simply add omni.asset_validator.core as a dependency of your tool (e.g. your Kit extension or other python module), derive a new class from BaseRuleChecker, and use the ValidationRulesRegistry to categorize your rule with the system. See the Core Python API for thorough details and example code. We even provide a small Testing API to ease unittesting your new rules against known USD layer files.


Put extra thought into your category name, your class name, your GetDescription() implementation, and the messages in any errors, warnings, or failures that your rule generates at runtime. These are the user-facing portions of your rule, and many users will appreciate natural language over engineering semantics.

Running the Validation Engine

Validation can be run synchronously (blocking) via ValidationEngine.validate(), or asynchronously via either ValidationEngine.validate_async() or ValidationEngine.validate_with_callbacks(). Currently validation within an individual layer file or Usd.Stage is synchronous. This may become asynchronous in the future if it is merited.

Validation Issues are captured in a Results container. Issues vary in severity (Error, Failure, Warning) and will provide detailed messages explaining the problem. Optionally, they may also provide detail on where the issue occured in the Usd.Stage and a suggestion (callable python code) for how it can be fixed automatically.

Fixing Issues automatically

Once validation Results have been obtained, they can be displayed for a user as plain text, but we also provide an automatic IssueFixer for some Issues. It is up to each individual rule to define the suggested fix via a python callable. See the Core Python API for more details.

Configuring Rules with Carbonite Settings

As with many Omniverse tools, omni.asset_validator.core is configurable at runtime using Carbonite settings. The following settings can be used to customize which rules are enabled/disabled for a particular app, company, or team.


  • enabledCategories/disabledCategories are lists of of glob style patterns matched against registered categories. Categories can be force-enabled using an exact match (no wildcards) in enabledCategories.

  • enabledRules/disabledRules are lists of of glob style patterns matched against class names of registered rules. Rules can be force-enabled using an exact match (no wildcards) in enabledRules.


These settings only affect a default-constructed ValidationEngine. Using the Python API, client code may further configure a ValidationEngine using enableRule(). In such cases, the rules may not even be registered with the ValidationRulesRegistry.

API and Changelog

We provide a thorough public API for the core validation framework and a minimal public testing API to assist clients in authoring new rules.