Feature: ID:004 - Simulate Multi-Body Physics - Base#

Property

Value

Internal ID

FET004_BASE_NEUTRAL

Description#

Features needed to support Simulate Multi-Body physics. This feature enables simulation of physically accurate motion and collisions for props and dynamic assets that have multibody bodies that need to be joined or simulated together. The enables real world “joints” to describe how two bodies work together. It is suitable for testing, validation, or reference applications where basic physical interactions are required.

Dependency Graph#

        flowchart LR
    FET003N["FET003_BASE_NEUTRAL\n0.1.0"]
    FET004N["FET004_BASE_NEUTRAL\n0.1.0"]
    FET003P["FET003_BASE_PHYSX\n0.1.0"]
    FET004P["FET004_BASE_PHYSX\n0.1.0"]
    FET004RN["FET004_ROBOT_PHYSX\n0.1.0"]
    FET022N["FET022_DRIVEN_JOINTS_NEUTRAL\n0.1.0"]
    FET022P["FET022_DRIVEN_JOINTS_PHYSX\n0.1.0"]

    FET004N --> FET003N
    FET004P --> FET003P
    FET004P --> FET004N
    FET022N --> FET004N
    FET022P --> FET004RN

    classDef current fill:#90EE90,stroke:#333
    classDef other fill:#fff,stroke:#333
    class FET004N,FET004P,FET004RN current
    class FET003N,FET003P,FET022N,FET022P other

Use Cases#

Products that consume this feature:

  • IsaacSim

  • MEGA

  • Lightwheel SOW1

Neutral Format#

Version 0.1.0#

Details

Used in Profiles#

This version is used in the following profiles:

Requirements#

Property

Value

Dependency

ID:003 - RBD Physics - Base - Neutral Format - v0.1.0

Pipelines Supported for this Feature#

Source file type:

  • .blend

    • Via Blender SimReady Add-ons

  • .mjcf

    • Via Blender SimReady Add-ons + MJCF2USD Tool

  • .step

    • Via Blender SimReady Add-ons + CAD Converter

MultiBody | Rigidbody Samples (Neutral)#

Benchmarks#

None.

NVIDIA Physx Format#

Version 0.1.0#

Details

Property

Value

Internal ID

FET004_BASE_PHYSX

Proprietary Techs

Physx

Used in Profiles#

This version is used in the following profiles:

Requirements#

Property

Value

Dependency

ID:003 - RBD Physics - Base - Nvidia Physx Format - v0.1.0

Dependency

ID:004 - Simulate Multi-Body Physics - Base - Neutral Format - v0.1.0

No additional requirements.

Pipelines Supported for this Feature#

Source file type:

  • .usd

    • Via CIP.

    • Convert from Neutral Format - Version 0.1.0.

MultiBody | Rigidbody Samples (Physx)#

MultiBody | Robot Rigidbody Samples (Physx)#

Benchmarks#

Robot PhysX Format (FET004_ROBOT_PHYSX)#

This variant is used in Robot-Body profiles (e.g. Robot-Body-Physx, Robot-Body-Runnable, Robot-Body-Isaac) for multi-body robot physics with PhysX. It uses the same multi-body and joint requirements as the base PhysX format, but with a different set of collision requirements.

RB.COL.001 exclusion#

RB.COL.001 (“Colliding Gprims must apply the Collision API”) is not enforced for FET004_ROBOT_PHYSX.

  • Reason: RB.COL.001 is too strict for Omniverse/Isaac Sim robot assets. In practice, nesting for CollisionAPI is allowed (e.g. collision shapes under non-Gprim hierarchy or applied in ways that RB.COL.001 would reject).

  • Effect: The Robot PhysX feature does not include RB.COL.001 in its requirement set. It does include RB.COL.002, RB.COL.003, and RB.COL.004 (mesh collision API, collider mesh, uniform scale), plus the other rigid-body and joint requirements listed in the feature JSON.

When authoring or validating robot USDs for Robot-Body profiles, do not require RB.COL.001 compliance; the validator configuration for this feature omits it by design.

Benchmarks#