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+
⛔	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	latest+
🔑	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
🔑	Assets must contain at least one Imageable Geometry	core-usd
🔑	Geometry shall be defined as such that the asset is correctly positioned and oriented at the origin (0,0,0).	core-usd
🔑	All geometry shall be represented as non-subdivided mesh primitives using the UsdGeomMesh schema.	core-usd
✅	Mesh geometry must be manifold	core-usd	latest+
✅	Mesh topology must be valid	core-usd	latest+
✅	Transparent physical bodies should be watertight to allow for simulation of light transmission and refraction.	core-usd
✅	Meshes should be positioned with xform ops rather than by “baking” transformations into point positions.	core-usd
✅	Repeated occurrences of identically shaped objects should have identical mesh connectivity	core-usd	Manual
✅	The pivot point of an asset should be positioned logically: at the center of the object’s base for ground plane objects, and at the center of rotation for objects that rotate around specific points.	core-usd
✅	All non-subdivided meshes must have normals.	core-usd	latest+
✅	Mesh normals values must be valid to produce correct shading.	core-usd
✅	The winding order of faces in a mesh must correctly represent the orientation (front/back) of the face.	core-usd
⛔	World space bounds must not exceed RTX limit.	rtx
🚀	Boundable geometry primitives must have valid extent values.	open-usd
🚀	Only include geometry that contributes to visualization or simulation	open-usd
🚀	Use efficient mesh boundaries for performance	rtx
🚀	Meshes should maintain appropriate scale and boundary volumes	rtx
🚀	Meshes should not overlap unnecessarily	core-usd
🚀	Meshes should not share the exact same space	core-usd
🚀	Use indexed primvars when values are repeated	core-usd	latest+
🚀	Use subdivision only when needed for smooth surfaces or displacement	core-usd	latest+
🚀	Only include primvars that are actively used	core-usd	latest+
🚀	Combine small meshes into larger ones where appropriate	core-usd
🚀	Use appropriate tessellation density for geometry	core-usd
🚀	Use time samples only when attribute values change	core-usd
🚀	Each vertex position should be unique	core-usd	latest+
🚀	Avoid tessellating primitive shapes	core-usd
🚀	Mesh topology should be without unused vertices, edges, or faces.	core-usd	latest+
🚀	Faces should have non-zero area.Faces where all vertices are co-linear or coincident waste memory and can cause rendering artifacts.	core-usd	latest+
🚀	The values of points must not exceed the limit at which a given precision can be represented using 32-bit floats.	core-usd
🚀	Meshes must be triangulated for optimal rendering performance and compatibility when considering automatic collider creation (convex-hull, convex-decomposition, etc…). Triangulating mesh will provide predictable results versus n-gons.	core-usd

Materials

Tags	Summary	Compatibility	Validator
🔑	Each renderable GPrim must have a computed material bound to it	core-usd
✅	Material bindings must use appropriate scope to ensure proper material assignment and inheritance.	open-usd	latest+
✅	Shader inputs must have correct types matching their shader specification to ensure proper material behavior and prevent runtime errors.	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+
✅	Each PBR texture channel must use the correct color space.	core-usd
🚀	Texture dimensions must not exceed 16,384 pixels on either axis to ensure optimal performance and memory usage in simulation environments.	open-usd	latest+

Physics

Rigid Bodies

Tags	Summary	Compatibility	Validator
🔑	MuJoCo collision shapes must apply MjcCollisionAPI on valid USD collision geometry.	other	MuJoCoColliderAPIChecker
🔑	MuJoCo mesh collision data must use valid MjcMeshCollisionAPI and convex-hull mesh collision authoring.	other	MuJoCoMeshCollisionAPIChecker
🔑	Newton colliders must use a valid Newton collision schema.	other	NewtonColliderAPIChecker
🔑	Authored Newton SDF attributes must be valid.	other	NewtonSDFAttributesChecker
🔑	NewtonMassAPI must be applied on an Xformable, and any authored Newton mass attributes must be valid.	other	NewtonMassAttributesChecker
🔑	CollisionAPI may only be applied to a UsdGeom Gprim or to an Xform that has PhysxMeshMergeCollisionAPI and whose collisionmeshes collection includes at least one Gprim.	physx
🔑	Assets must contain at least one rigid body	open-usd
🔑	Invisible collision meshes must have their purpose attribute set to ‘guide’ to be properly excluded from rendering.	open-usd
🔑	Colliding Gprims must apply the Collision API.	open-usd
🔑	Assets must contain at least two rigid bodies	open-usd
✅	MeshCollisionAPI may only be applied to a UsdGeom Mesh or to a prim that has PhysxMeshMergeCollisionAPI. CollisionAPI is required whenever MeshCollisionAPI is applied.	physx
✅	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 can not be nested unless xformOp reset xform stack is used.	open-usd	latest+
✅	Rigid bodies have to be UsdGeomXformable prims without skew matrix.	open-usd	latest+
✅	Rigid bodies should not be nested unless they are connected by a joint.	open-usd
✅	UsdPhysicsMeshCollisionAPI may only be applied to UsdGeom.Mesh prims, and any prim with MeshCollisionAPI must also have UsdPhysicsCollisionAPI applied.	open-usd	RigidBodyColliderMeshChecker
✅	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+
💎	Rigid bodies or their descendant collision shapes must have a mass specification.	open-usd
💎	Rigid bodies or their descendent collision shapes may have detailed mass properties including density, center of mass, and inertia tensor. When authored, these detailed mass properties must be internally consistent.	open-usd
💎	Every rigid body must have a valid (positive) physics:mass on itself or on at least one of its child colliders. Nested rigid body subtrees are excluded from the traversal. Negative mass is always a failure.	open-usd
💎	Enabled rigid bodies must have collision geometry.	open-usd

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 kinematic bodies.	open-usd	latest+
✅	Articulations are not allowed on static bodies.	open-usd	latest+
💎	For stable and fast simulations of kinematic chains, an asset should define an articulation.	open-usd