Feature: FET_003_NEWTON

Property	Value
Feature Name	FET_003_NEWTON
Runtime	NEWTON
Proprietary Techs	Newton
Latest Version	0.1.0

Description

The Newton Rigid Body Physics feature defines the Newton runtime contract for assets that can be simulated as rigid bodies with Newton-compatible collision schemas.

An asset that satisfies this feature carries the Standard rigid-body and collider requirements plus a Newton collider representation. Newton mesh colliders can use either NewtonMeshCollisionAPI for ordinary mesh collision or NewtonSDFCollisionAPI for SDF-backed or hydroelastic collision, but a single collider prim must not use both representations at once.

Newton Authoring Notes

Editorial guidance (does not change the requirement IDs below):

• NewtonCollisionAPI carries the shared contact tuning. newton:contactMargin (default 0) inflates the collision surface outward; newton:contactGap (default -inf = engine default; samples author 0) expands the AABB so contacts are detected earlier.

• NewtonMeshCollisionAPI is the ordinary mesh path. When physics:approximation = "convexHull", newton:maxHullVertices (default -1 = exact hull) caps the hull vertex count. Newton uses the inherited physics:approximation, so keep it set to a value the collider intends (convexHull, convexDecomposition, etc.).

• NewtonSDFCollisionAPI is the SDF/hydroelastic path and is mutually exclusive with NewtonMeshCollisionAPI. Author SDF tuning only when the collision intent is known: newton:sdfMaxResolution must be divisible by 8, newton:sdfTextureFormat is one of uint8/uint16/float32, and newton:sdfNarrowBandInner < newton:sdfNarrowBandOuter.

• NewtonMassAPI (NEWTON.MAS.001) applies on an Xformable (body or collision Gprim) and extends PhysicsMassAPI. newton:inertia, when authored non-empty, is a compact symmetric tensor [Ixx, Iyy, Izz, Ixy, Ixz, Iyz] (exactly 6 finite elements; non-negative diagonal) that overrides physics:diagonalInertia/physics:principalAxes; newton:massModel is solid or shell; newton:shellThickness (default -inf = solver chooses) must be finite and > 0 when authored. Author only when overriding the neutral mass resolution.

• NewtonMaterialAPI (NEWTON.MAT.001) applies on the physics Material bound to the collider and adds Newton contact/friction tuning (newton:torsionalFriction, newton:rollingFriction, and the newton:contact* attributes) on top of PhysicsMaterialAPI. Aligned with the UsdPhysicsMaterialAPI convention (PMT.001), validation checks placement only: the schema must sit on a UsdShade.Material that also carries PhysicsMaterialAPI. The newton:* values are trusted rather than policed (leave the contact attributes at the -inf sentinel, or unauthored, to use the Newton engine default).

• Keep the composed Newton stage strictly Newton (RV.011): no Mjc* / Physx* schemas or attributes, and no physics:approximation = "sdf" string.

Dependency Graph

This feature has no JSON feature dependencies. It carries an explicit runtime-specific requirement list so the Newton runtime contract can be validated directly.

        flowchart LR
    FET003N["FET_003_NEWTON\n0.1.0"]
    FET004N["FET_004_NEWTON\n0.1.0"]

    FET004N --> FET003N

    classDef current fill:#90EE90,stroke:#333
    classDef other fill:#fff,stroke:#333
    class FET003N current
    class FET004N other
    

Use Cases

• Newton runtime rigid-body simulation for USD assets.

• Runtime-layer validation for Newton mesh collision or Newton SDF collision.

• Physics payload variants where Newton can be switched alongside PhysX on the same asset root.

Requirements

Version 0.1.0

Details

Used in Profiles

• None documented.

Feature Dependencies

None.

Requirement List

• Capability: Physics Bodies/Rigid Bodies

  • Requirements:

    • Collider-Capability

      • RB.COL.001 | Version 0.1.0

      • Rule | Implementation

    • Mesh-Collision-API

      • RB.COL.002 | Version 0.1.0

      • Rule | Implementation

    • Collider-Mesh

      • RB.COL.003 | Version 0.1.0

      • Rule | Implementation

    • Collider-Non-Uniform-Scale

      • RB.COL.004 | Version 0.1.0

      • Rule | Implementation

    • Rigid-Body-Capability

      • RB.001 | Version 0.1.0

      • Rule | Implementation

    • Rigid-Body-Schema-Application

      • RB.003 | Version 0.1.0

      • Rule | Implementation

    • Rigid-Body-No-Instancing

      • RB.005 | Version 0.1.0

      • Rule | Implementation

    • Rigid-Body-Mass

      • RB.007 | Version 0.1.0

      • Rule | Implementation

    • Rigid-Body-Schema-No-Skew-Matrix

      • RB.009 | Version 0.1.0

      • Rule | Implementation

    • Invisible-Collision-Mesh-Has-Purpose

      • RB.010 | Version 0.1.0

      • Rule | Implementation

    • Newton-Collider-API

      • NEWTON.COL.001 | Version 0.1.0

      • Rule | Implementation

    • Newton-SDF-Attributes

      • NEWTON.COL.002 | Version 0.1.0

      • Rule | Implementation

    • Newton-Mass-Attributes

      • NEWTON.MAS.001 | Version 0.1.0

      • Rule | Implementation

• Capability: Physics Bodies/Physics Materials

  • Requirements:

    • Newton-Material-Attributes

      • NEWTON.MAT.001 | Version 0.1.0

      • Rule | Implementation

Pipelines

Source file type:

• .usd / .usda

  • Via USD authoring tools that emit Newton runtime physics payload layers.

Validation or runtime pipeline:

• SimReady validation - verifies the Newton Rigid Body Physics requirement IDs listed in the selected FET_003_NEWTON manifest.

• Newton runtime payload validation - verifies that the asset can expose a Newton physics payload variant alongside other physics runtimes.

Samples

• sample_content/common_assets/props_general/obs_orange_a02/simready_usd/sm_obs_orange_a02_01.usd

Benchmarks

• FET003 Physics

  • ground_drop

  • slope_drop

Adapters

From Feature	To Feature	Adapter	Status	Notes
FET_003_STANDARD@0.1.0	FET_003_NEWTON@0.1.0	nv_core/cip_specs/asset_handler_modules/neutral_to_newton	Done	Computes mesh extents and applies Newton mesh-collision schemas (newton:contactGap), and applies NewtonMaterialAPI with default friction tuning to bound physics materials.