UsdUtilsComplianceChecker migration

The following rules need to be migrated to the new validation framework.

Instructions

1. Review the list of rules to be migrated
2. Add your name in the Volunteer column to let others know you're working on the validator
3. Submit a PR!
4. (optional) Update the status on this tracker.

Tracker

#	Status	Volunteer	Rule	Group	Details
1	To do	tbd	StageMetadataCheckerUpAxisY	ARKit	usdStage metadata of upAxis must be Y
2	To do	tbd	TextureChecker	ARKit	only support texture of type exr jpg jpeg or png, nothing else is allowed for arkit.
3	To do	tbd	ARKitPackageEncapsulationChecker	ARKit	For a package root layer, no referenced files should be outside this package.
4	To do	tbd	ARKitLayerChecker	ARKit	extensions of any layer in a arkit package.
5	To do	tbd	ARKitPrimTypeChecker	ARKit	ARkit can have only specific prim types.
6	To do	tbd	ARKitShaderCheckr	ARKit	ARKit shaders must have id as their implementationSource, + other checks
7	To do	tbd	ARKitMaterialBindingChecker	ARKit	material binding rels must have valid taget
8	To do	tbd	ARKitFileExtensionChecker	ARKit	Only layers and textures are allowed in a package.
9	To do	tbd	MissingReferenceChecker	coreUSD	Composed USD Stage should not contain any unresolvable asset dependencies, in every variant(s) of the asset, when using default asset resolver.
10	PR submitted	beersandrew	StageMetadataChecker	coreUSD	Various usdStage metadata checks, such as upAxis, metersPerUnit, defaultPrim.
11	To do	tbd	PrimEncapsulationRule	coreUSD, usdGeom, usdShade	Though this is a generic rule, currently it only is being used to test for UsdGeomBoundable and UsdShade related concepts. (1) Boundables may not be nested under Gprims (2) Connectable prims (eg Shaders, Materials, etc) can only be nested inside other container-like connected prims.
12	To do	tbd	NormalMapTexture	UsdPreviewSurface (usdShadeShader)	Rule governing nodes that feed the inputs:normal of a UsdPreviewSurface.
13	To do	tbd	MaterialBindingAPIAppliedChecker	UsdShade	A prim providing a material binding, must have MaterialBindingAPI applied. (This and other APISchema based test might get bundled in a generic coreUSD test instead of specific multiple domain level tests)
14	Done	tallytalwar	ShaderPropertyTypeConformanceChecker	UsdShadeShader	UsdShadeShader property types must conform to property types from their sdr representations.
15	To do	tbd	SkelBindingAPIAppliedChecker	UsdSkel	A prim providing a skelBinding properties, must have SkelBindingAPI applied. (This and other APISchema based test might get bundled in a generic coreUSD test instead of specific multiple domain level tests)
16	To do	tbd	ByteAlignmentChecker	usdz	Files in a usdz package must align to 64 bytes
17	To do	tbd	CompressionChecker	usdz	Files within usdz package should not be compressed or encrypted.

Helpful References

• USD Validation Proposal Recording
• usdCore example
• usdShade example

Best Practices

• “Keyword” metadata for a validator belonging to a schemaDomain should be: Validators , Example: UsdCoreValidators, UsdShadeValidators.
• Prefix plugin based validators with plugin name. Example: “usd:CompositionErrorTest”, “usdShade:ShaderSdrCompliance”.
• Provide public tokens for validator name and keyword metadata. Examples: usdCore | usdShade
• Logical encapsulation of Validator rules.
• Granular validation rules using PrimValidateTask vs StageValidateTask (for improved performance)