Add manager-owned declarative collision filtering

[ooctipus]

Description

Add backend-neutral, physics-manager-owned collision filtering while making replicated-world isolation a default cloner policy.

Architecture

• CloneCfg owns clone strategy, environment template, physics replication, and world isolation. isolate_environments=True is the default.
• ClonePlan carries the resolved clone policy. InteractiveScene passes its complete cloner configuration into planning; it neither owns nor applies collision filtering.
• cloner.replicate(plan) establishes one backend-independent assembly barrier: collider topology is assembled, the active PhysicsManager realizes collision policy, and native physics state is then built.
• PhysicsCfg.collision_filter owns collider-granular policy through named CollisionGroupCfg entries. Prim selectors use whole-path regular-expression matching. Group relationships are symmetric, deny-wins, and support per-group allow-list inversion.

This supports non-transitive policies such as robot-object and object-support contact with robot-support disabled. It also supports multiple collider representations on one asset: nut/bolt SDF colliders can contact only each other while their convex colliders remain active against other objects.

Backend realization

• Isaac Sim PhysX compiles assembled colliders into exclusive effective profiles, composes manager policy with world isolation, and preserves authored collision-group and filtered-pair denials.
• Newton maps each authored collider to every generated native shape, including convex-decomposition pieces, and lowers policy to native shape-filter pairs during replicated builder assembly.
• OVPhysX is a first-class implementation of the same manager contract. It uses native environment IDs for the GPU isolation-only fast path and full-stage realization for explicit semantic groups, non-native isolation, and composed authored policy.

Compatibility and migration

• InteractiveSceneCfg.filter_collisions and InteractiveScene.filter_collisions() are removed; filtering is automatic at the physics-manager barrier.
• CloneCfg.replicate_physics is canonical. The top-level InteractiveSceneCfg.replicate_physics field remains as a deprecated compatibility alias and is normalized into a copied CloneCfg.
• isaaclab.cloner.filter_collisions(), legacy low-level plan arguments, and asset/terrain collision_group fields remain as deprecated compatibility surfaces.
• Exact-path selection needs no extra flag: a selector can use an exact regular expression (optionally ending in $), while descendant selection is expressed directly with patterns such as .*/colliders/convex.

Type of change

• New feature
• Deprecation/migration
• Documentation update

Release backport

• Backport this pull request to the active release branch after it merges into develop

Screenshots

Not applicable.

Validation

• 65 focused cross-backend collision-filter, lifecycle, and clone-plan tests passed.
• 103 core cloner tests, 49 Newton cloner tests, and 57 OVPhysX cloner/scene-backend tests passed.
• Real OVPhysX 0.5.11 CPU and GPU stepping verified filtered bodies pass through while controls collide, including replicated semantic groups, authored-policy composition, and native GPU environment-ID isolation.
• Task templates passed isolated generation and syntax/type validation.
• Ruff formatting/lint, Python compilation, diff checks, and changelog validation against the PR base passed.
• A centralized file/dependency audit confirmed there is no scene-owned filtering API, duplicate backend compiler, obsolete collision-filter wrapper, or descendant-selection flag.

Native Isaac Sim stepping was not available in this workspace and is left to CI.

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 added a changelog fragment under source/<pkg>/changelog.d/ for every touched package
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[greptile-apps]

Greptile Summary

This PR introduces manager-owned declarative collision filtering and moves replicated-environment isolation into the clone lifecycle.

• Adds named, regex-selected collision groups with symmetric deny-wins and allow-list inversion semantics.
• Adds a collision-filter assembly barrier between USD authoring and native physics replication.
• Implements backend-specific realization for Isaac Sim PhysX and Newton, with explicit capability handling for OvPhysX.
• Migrates InteractiveScene, direct tasks, examples, documentation, and tests to pass isolation intent during replication.

Confidence Score: 5/5

The PR appears safe to merge with no concrete correctness, security, or repository-rule violations identified.

The manager barrier, clone-plan propagation, and backend realizations are internally consistent, and the added tests cover the principal policy, lifecycle, isolation, and authored-filter preservation paths.

Important Files Changed

Filename	Overview
source/isaaclab/isaaclab/cloner/replicate_session.py	Splits context dispatch around a validated, one-shot collision-filter assembly barrier and forwards environment-isolation intent.
source/isaaclab/isaaclab/physics/physics_manager.py	Adds collision-policy configuration, validation, barrier enforcement, backend dispatch, and lifecycle cleanup.
source/isaaclab/isaaclab/physics/_collision_filter.py	Compiles selector membership and symmetric deny-wins group semantics.
source/isaaclab_physx/isaaclab_physx/physics/collision_filter.py	Compiles assembled USD colliders, authored constraints, manager policy, and environment isolation into exclusive PhysX profiles.
source/isaaclab_newton/isaaclab_newton/cloner/collision_filter.py	Maps authored collider endpoints to Newton shapes and lowers declarative and authored denials into native filter pairs.
source/isaaclab_ov/isaaclab_ov/physics/ovphysx_manager.py	Realizes environment isolation through native environment IDs or deferred full-stage USD groups and rejects unsupported semantic groups.
source/isaaclab/isaaclab/scene/interactive_scene.py	Moves automatic isolation into scene replication and guards the deprecated post-barrier filtering API.

Sequence Diagram

sequenceDiagram
    participant C as Scene or direct caller
    participant R as Cloner
    participant U as USD contexts
    participant M as Physics manager
    participant P as Native physics contexts
    C->>R: Publish ClonePlan and isolation intent
    R->>U: Replicate negative-priority stage rows
    U-->>R: Assembled collider topology
    R->>M: Apply isolation and declarative policy
    M-->>R: Backend-specific filtering realized
    R->>P: Replicate priority-zero-or-later rows
    P-->>C: Constructed physics model

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_{Reviews (1): Last reviewed commit: "Add manager-owned collision filter polic..." | Re-trigger Greptile}

[isaaclab-review-bot]

Isaac Lab Review Bot

The manager-owned collision-filter policy and clone-lifecycle barrier are coherently integrated across PhysX, Newton, and OvPhysX. One scalability concern remains in the default PhysX environment-isolation path: generated collision groups enumerate every collider instead of retaining compact environment-root membership.

• Design and architecture: The negative-priority stage contexts → manager collision-filter barrier → native physics contexts ordering is coherent, with environment isolation owned by cloning and semantic collider policy owned by PhysicsCfg. No actionable architecture issue was established beyond the PhysX representation-size concern.
• API: The new CollisionFilterCfg, CollisionGroupCfg, ClonePlan.env_template, and isolate_environments surfaces are exported, documented, and accompanied by migration guidance for the deprecated post-cloning filtering workflow. No supported public API break was demonstrated by the candidate findings.
• Implementation: PhysX currently emits explicitOnly generated groups containing one relationship target per collider. For the common isolation-only case, this replaces the previous single expandPrims environment-root target with collider-count-proportional authored data, materially increasing stage size for large replicated scenes. Preserve compact environment-root membership when an effective profile covers the whole environment.

Minor fixes needed. Posted 1 actionable finding inline.

Automated review; human maintainers own approval decisions.

[isaaclab-review-bot]

🟡 Warning · Implementation — Per-collider includes scale environment isolation

Generated groups use explicitOnly with one relationship target per collider path. On the default PhysX path (filter_collisions=True, no collision_filter cfg) each world forms a single profile, so authored targets grow from one env-root expandPrims include per environment to the total collider count across the stage — a large multiplier at thousands of environments. Keep env-root expandPrims includes when a profile covers a whole environment.

[ooctipus]

Addressed in a23a984. The isolation-only path now returns through the existing compact _author_collision_groups helper, so it authors one expandPrims environment-root target per environment and never discovers or enumerates colliders. Per-collider explicit membership is retained only when a semantic collider-level policy is configured.