[Newton] Refactors Simulation Manager and Context

[ooctipus]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context.
List any dependencies that are required for this change.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (existing functionality will not work without user modification)
• Documentation update

Screenshots

Please attach before and after screenshots of the change if applicable.

Checklist

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[kellyguo11]

was this from Piotr's changes?

[ooctipus]

yes I think so

[kellyguo11]

would it help with the merge if we also implement this first?

[ooctipus]

I got the newton scene data provider kind of working in dev/newton, but I thought I'd like to reserve the implementation detail to @matthewtrepte and i might be beneficial for him to directly work on develop and not worry about dev/newton. Maybe

[AntoineRichard]

Look great! Thanks @ooctipus! I would start moving some files about in the correct modules / package just to make sure we can make things work. We'd need to separate the PhysX / Newton Managers and move them to their respective modules. Same with the visualizers, scene data providers etc...

[greptile-apps]

Greptile Summary

Refactored simulation architecture to extract physics backend logic from SimulationContext into dedicated PhysicsManager hierarchy, introduced SceneDataProvider abstraction for visualizers/renderers, and renamed Omniverse visualizer to Kit.

Key architectural changes:

• Extracted PhysX and Newton physics logic from SimulationContext (1760→520 lines) into PhysxManager and NewtonManager that extend new abstract PhysicsManager base class
• Introduced unified callback system via PhysicsEvent enum (MODEL_INIT, PHYSICS_READY, STOP) replacing backend-specific callbacks
• Created SceneDataProvider interface allowing visualizers to access scene data (transforms, velocities, contacts) without tight coupling to physics backends
• Moved Newton manager from sim/_impl/ to physics/ package for better organization
• Renamed OVVisualizer → KitVisualizer and omniverse → kit visualizer type
• Updated 85 files including all task configs to use new import paths and API patterns

Impact:

• Breaking change: visualizer type omniverse renamed to kit
• Breaking change: import paths changed for Newton config (sim._impl.newton_manager_cfg → physics.newton_manager_cfg)
• Assets now register callbacks via PhysicsManager.register_callback() instead of backend-specific methods

Confidence Score: 4/5

• Large architectural refactoring with good separation of concerns; breaking changes are clearly scoped to config imports and visualizer naming
• This is a well-structured refactoring that improves maintainability by separating physics backend concerns. The changes follow clear patterns (extract class, introduce interface), callbacks are properly migrated to unified system, and the scope is appropriate for the PR title. However, confidence is not higher due to: (1) large surface area with 85 files changed across multiple subsystems, (2) breaking changes to public API (visualizer names, import paths), (3) complex callback lifecycle management that could have edge cases, and (4) limited test coverage updates visible in the diff
• Pay close attention to source/isaaclab/isaaclab/physics/physx_manager.py (new animation recording lifecycle), source/isaaclab/isaaclab/sim/simulation_context.py (singleton pattern and cleanup order), and task config files to ensure backward compatibility isn't broken unintentionally

Important Files Changed

Filename	Overview
source/isaaclab/isaaclab/sim/simulation_context.py	Heavily refactored to delegate physics to PhysicsManager, simplifying from 1760+ lines to ~520 lines; visualization now uses scene data providers
source/isaaclab/isaaclab/physics/physics_manager.py	New abstract base class introducing unified callback system for physics lifecycle events across backends
source/isaaclab/isaaclab/physics/physx_manager.py	New PhysX manager extracting PhysX-specific logic from SimulationContext, including animation recording and fabric updates
source/isaaclab/isaaclab/physics/newton_manager.py	Moved from sim/_impl/ to physics/, now extends PhysicsManager with unified callback system
source/isaaclab/isaaclab/sim/scene_data_providers/scene_data_provider.py	New backend-agnostic interface for visualizers/renderers to access scene data (transforms, velocities, contacts)
source/isaaclab/isaaclab/sim/scene_data_providers/physx_scene_data_provider.py	PhysX implementation of scene data provider, supports body poses via PhysX tensor views with XformPrimView fallback
source/isaaclab/isaaclab/visualizers/visualizer.py	Refactored base class to use SceneDataProvider instead of direct simulation access
source/isaaclab/isaaclab/assets/asset_base.py	Switched from NewtonManager.add_on_start_callback to PhysicsManager.register_callback with unified PhysicsEvent

Class Diagram

%%{init: {'theme': 'neutral'}}%%
classDiagram
    class SimulationContext {
        +SimulationCfg cfg
        +PhysicsManager physics_manager
        +SceneDataProvider scene_data_provider
        +initialize_visualizers()
        +reset()
        +step()
        +forward()
    }
    
    class PhysicsManager {
        <<abstract>>
        +initialize(sim_context)
        +reset(soft)
        +step()
        +forward()
        +register_callback(callback, event, order)
        +deregister_callback(id)
    }
    
    class PhysxManager {
        +AnimationRecorder _anim_recorder
        +_warmup_and_create_views()
        +_configure_physics()
        +step()
    }
    
    class NewtonManager {
        +ModelBuilder _builder
        +Model _model
        +State _state_0
        +initialize_solver()
        +step()
    }
    
    class SceneDataProvider {
        <<interface>>
        +get_transforms()
        +get_velocities()
        +get_newton_model()
        +get_usd_stage()
        +get_metadata()
    }
    
    class PhysxSceneDataProvider {
        +_stage
        +_physics_sim_view
        +_newton_model
        +get_transforms()
        +get_velocities()
    }
    
    class NewtonSceneDataProvider {
        +_model
        +_state
        +get_transforms()
        +get_newton_model()
    }
    
    class Visualizer {
        <<abstract>>
        +SceneDataProvider scene_data_provider
        +initialize(provider)
        +step(dt, state)
        +close()
    }
    
    class KitVisualizer {
        +_viewport_window
        +step(dt, state)
    }
    
    class NewtonVisualizer {
        +_window
        +step(dt, state)
    }
    
    class RerunVisualizer {
        +_rec
        +step(dt, state)
    }
    
    SimulationContext --> PhysicsManager : uses
    SimulationContext --> SceneDataProvider : creates
    SimulationContext --> Visualizer : manages
    PhysicsManager <|-- PhysxManager : extends
    PhysicsManager <|-- NewtonManager : extends
    SceneDataProvider <|.. PhysxSceneDataProvider : implements
    SceneDataProvider <|.. NewtonSceneDataProvider : implements
    Visualizer <|-- KitVisualizer : extends
    Visualizer <|-- NewtonVisualizer : extends
    Visualizer <|-- RerunVisualizer : extends
    Visualizer --> SceneDataProvider : uses

Loading

_{Last reviewed commit: d291a11}

[greptile-apps]

_{85 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}