Requirements Index

Core

Atomic Asset

Tags	Summary	Compatibility	Validator
🔑	Asset references should use anchored paths	core-usd	latest+
🔑	Asset must use only supported file types	open-usd	latest+
🔑	Asset paths should use forward slashes for cross-platform portability	core-usd	latest+
⛔	Texture UDIMs are not supported in USDZ files in NVIDIA Omniverse	kit	latest+

Units

Tags	Summary	Compatibility	Validator
🔑	Stage must specify upAxis to define the orientation of the stage	core-usd	latest+
🔑	Stage must specify metersPerUnit to define the linear unit scale	core-usd	latest+
🔑	Stage must specify upAxis = “Z” to define the orientation of the stage	core-usd
🔑	Stage must specify metersPerUnit = 1.0 to define the linear unit scale	core-usd	latest+
✅	Stage must specify kilogramsPerUnit to define the mass unit scale, if physics objects are present in the stage.	core-usd
✅	Must apply corrective transforms for different units	core-usd
✅	Stage must specify timeCodesPerSecond, if timesamples are present in the stage.	core-usd

Visualization

Geometry

Tags	Summary	Compatibility	Validator
🔑	Geometry shall be defined as such that the asset is correctly positioned and oriented at the origin (0,0,0).	core-usd	latest+
🔑	All geometry shall be represented as non-subdivided mesh primitives using the UsdGeomMesh schema.	core-usd	latest+
✅	Mesh geometry must be manifold	core-usd	latest+ latest+
✅	Mesh topology must be valid	core-usd	latest+
✅	Meshes should be positioned using xform ops, not by embedding positions into point positions.	core-usd	Manual
✅	All non-subdivided meshes must have normals.	core-usd	latest+
✅	Mesh normals values must be valid to produce correct shading.	core-usd	latest+ latest+
✅	The winding order of faces in a mesh must correctly represent the orientation (front/back) of the face.	core-usd	latest+ latest+
✅	Meshes made from non opaque materials shall have thickness	core-usd
⛔	World space bounds must not exceed RTX limit.	rtx	latest+
🚀	Boundable geometry primitives should have valid extent values.	open-usd	latest+
🚀	Only include geometry that contributes to visualization or simulation	open-usd	latest+
🚀	Use efficient mesh boundaries for performance	rtx	latest+
🚀	Meshes should maintain appropriate scale and boundary volumes	rtx	latest+
🚀	Meshes should not overlap unnecessarily	core-usd
🚀	Meshes should not share the exact same space	core-usd	latest+
🚀	Use indexed primvars when values are repeated	core-usd	latest+ latest+
🚀	Do not subdivide meshes with Normals.	core-usd	latest+
🚀	Only include primvars that are actively used	core-usd	latest+
🚀	Remove meshes from the scene that are below the extent size threshold.	core-usd
🚀	Use appropriate tessellation density for geometry	core-usd
🚀	Use time samples only when attribute values change	core-usd	latest+
🚀	Each vertex position should be unique	core-usd	latest+
🚀	Avoid tessellating primitive shapes	core-usd	latest+
🚀	Mesh topology should be without unused vertices, edges, or faces.	core-usd	latest+ latest+
🚀	Faces should have non-zero area.	core-usd	latest+ latest+
🚀	The values of the points attribute must not exceed the limit at which a given precision can be represented using 32-bit floats.	core-usd	latest+
🚀	Use appropriate vertex count for geometry	core-usd	latest+
🚀	Meshes should use instancing if they are identical apart from their world space location	core-usd	latest+
🚀	Repeated occurrences of identically shaped objects should have identical mesh connectivity	core-usd	latest+
🚀	Boundable geometry should have non-zero extents in at least one dimension.	core-usd	latest+
🚀	Faces should not be lamina.	core-usd	latest+
🚀	Do not author unused texture coordinates.	core-usd	latest+
🚀	Avoid invisible prims when deactivation is more appropriate.	core-usd	latest+
🚀	Use appropriate mesh count for scene	rtx	latest+

Materials

Tags	Summary	Compatibility	Validator
✅	Material bindings must use appropriate scope to ensure proper material assignment and inheritance.	open-usd	latest+
✅	MDL material source assets must be properly referenced and accessible to ensure material loading and rendering.	open-usd	latest+
✅	MDL Shaders must standard OpenUSD shader source attributes to ensure compatibility.	kit-107+	latest+
✅	Material attributes must comply with the UsdPreviewSurface specification to ensure consistent rendering and viewer compatibility.	open-usd	latest+
🚀	Using fewer materials can result in better performance.	open-usd	latest+

Ground Truth

Semantic Labels

Tags	Summary	Compatibility	Validator
🔑	All geometry prims must be semantically labeled.	core-usd	latest+
✅	Semantic labels must use the SemanticsLabelsAPI schema	open-usd	latest+
✅	If the Wikidata ontology is used, Q-Codes must be valid, properly formatted, and retrievable from wikidata.org.	omniverse	latest+
⛔	Semantic label attributes must not contain time samples	rtx	latest+

Dense Captions

Tags	Summary	Compatibility	Validator
🔑	The Root Prim must inlcude documentation metadata that describes the 3D Asset.	core-usd
💎	Prims representing sub-objects or parts within the asset should be documented with additional dense captions.	core-usd

Non-Visual Sensors

Non-Visual Surface Properties

Tags	Summary	Compatibility	Validator
🔑	Materials must specify additional “non-visual” material attributes	rtx	latest+
✅	Materials must specify a base material type	rtx	latest+
✅	Materials must specify surface coating	rtx	latest+
✅	Attributes must be on bound materials	rtx
✅	Properties must be consistent with visual materials	rtx
✅	Properties must not be time-varying	rtx	latest+

Physics

Rigid Bodies

Tags	Summary	Compatibility	Validator
🔑	Assets must contain at least one rigid body	open-usd
🔑	Colliding Gprims must apply the Collision API.	open-usd
✅	Rigid bodies have to be UsdGeomXformable prims.	open-usd	latest+
✅	Rigid bodies cannot be part of a scene graph instance.	open-usd	latest+
✅	Rigid bodies have to be UsdGeomXformable prims without skew matrix.	open-usd	latest+
✅	If an asset is expected to be static (no movement happens), it can not contain a rigid body, only a Collider body.	open-usd
✅	The Mesh Collision API can only be assigned to Mesh Prims.	open-usd
✅	The collision shape scale must be uniform for the following geometries: Sphere, Capsule, Cylinder, Cone & Points.	open-usd	latest+
⛔	In PhysX based simulators, like Omniverse Isaac Sim, Rigid bodies can not be nested unless xformOp reset xform stack is used.	physx	latest+
💎	Rigid bodies or their descendent collision shapes should have a mass & their other inertial properties explicitly specified.	open-usd	latest+

Joints & Articulations

Tags	Summary	Compatibility	Validator
🔑	Rigid bodies which are not free floating should be connected using joints.	open-usd
✅	Targets set to Body0 and Body1 relationships must exist.	open-usd	latest+
✅	Body0 and Body1 relationships must not have more than one target.	open-usd	latest+
✅	Articulation roots cannot be nested.	open-usd	latest+
✅	Articulations are not allowed on static bodies.	open-usd	latest+
⛔	In PhysX based simulators, like Omniverse Isaac Sim, Articulations are not allowed on kinematic bodies.	physx	latest+
💎	For stable and fast simulations of kinematic chains, an asset should define an articulation.	open-usd

Hierarchy

Hierarchy

Tags	Summary	Compatibility	Validator
🔑	Prim hierarchy must have a single root prim.	open-usd
🔑	The root prim of the asset hierarchy must be transformable	other
🔑	Stage must specify a default prim to define the root entry point.	open-usd	latest+
🔑	Prims representing objects or groups that require placement (including the asset root) shall be xformable.	open-usd	Manual
🔑	Origins of prims representing objects or groups that require placement should be positioned intentionally	core-usd	Manual
✅	Transformations on prims representing objects or groups that require placement should conform to the UsdGeomXformCommonAPI.	open-usd
✅	Geometry should be grouped in a way that is logical for the object’s structure.	open-usd	Manual
✅	For articulated assets without joint definitions, the prim hierarchy should reflect the kinematic chain.	open-usd
🚀	Avoid large numbers of child prims under a parent xform	open-usd	latest+
🚀	Avoid empty leaf nodes in scene hierarchy	open-usd	latest+