# Description

The comment was saying there are 3 origins, when only 2 were instantiated

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with `./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my feature works
- [x] 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

Verification agents flagged five issues against the previous two
commits and one issue-isaac-sim#876 gap that the first pass missed.

1. Newton using-kamino.rst literalinclude path was one level short
   (../../../../../ → ../../../../../../). The previous depth resolved
   to a non-existent /docs/source/isaaclab_tasks/... and would have
   broken the sphinx build.

2. PhysX supported-features.rst listed Ray Caster, Visuo-tactile, and
   Camera as PhysX-specific sensors. Ray Caster and Camera are
   implemented in isaaclab core (backend-agnostic); Visuo-tactile lives
   in isaaclab_contrib. Reframe the section to separate PhysX-implemented
   sensors from backend-agnostic ones. Drop the unverifiable
   "path-traced" qualifier on the RTX renderer claim.

3. OvPhysX stub referenced only PR isaac-sim#5426 and PR isaac-sim#5459. The actual
   in-flight set spans six PRs: isaac-sim#5426 (merged), isaac-sim#5459, isaac-sim#5422, isaac-sim#5421,
   isaac-sim#5570, isaac-sim#5589. List them all with merge state, and reword "primary
   covered surfaces" to reflect that most are still open PRs.

4. backends/index.rst feature matrix said OvPhysX sensor coverage was
   "Partial" — actually only RigidObject is merged. Replace the
   matrix rows with concrete "In-flight (PR #...)" / "Not yet" cells.

5. Issue isaac-sim#876 asked to "review the limitations list and update it." The
   previous pass only reworded the intro. Refresh the task list against
   develop's actual newton_mjwarp coverage, add Shadow Hand / Shadow
   Hand Over / cabinet / dexsuite / rough-terrain locomotion, and
   replace the rigid bullet list with a discovery recipe so the list
   stops bit-rotting.

Tidies up the Newton subdir layout so file names mirror the PhysX
subdir and the per-solver split asked for in isaac-sim#876.

* solver-transitioning.rst → mjwarp-solver.rst
  Retitled "MJWarp Solver"; intro rewritten as a solver doc (no longer
  framed as a PhysX→Newton transition).

* using-kamino.rst → kamino-solver.rst
  Retitled "Kamino Solver". Label renamed from `newton-using-kamino`
  to `newton-kamino-solver` to match the new file name.

* limitations-and-known-bugs.rst → supported-features.rst
  Retitled "Supported Features" to mirror PhysX's same-named page.

Newton index toctree updated, and the doc/ref cross-references in
supported-features.rst and the Newton index updated to the new names.

…5637)

# Description

Restructures the physics-backend documentation to give each backend a
first-class home and to add the cross-backend orientation pages asked
for in
[isaac-sim/IsaacLab-Internal#876](isaac-sim/IsaacLab-Internal#876).

**Structure**

```
docs/source/overview/core-concepts/physical-backends/
├── index.rst                 ← user-facing hub + feature-support matrix
├── solver-comparison.rst     ← cross-backend behavioural differences
├── physx/
│   ├── index.rst
│   ├── installation.rst
│   ├── configuration.rst     ← PhysxCfg tuning knobs
│   └── supported-features.rst
├── newton/
│   ├── index.rst
│   ├── installation.rst
│   ├── supported-features.rst   (was experimental-features/.../limitations-and-known-bugs.rst)
│   ├── mjwarp-solver.rst        (was experimental-features/.../solver-transitioning.rst)
│   └── kamino-solver.rst        (was experimental-features/.../using-kamino.rst)
└── ovphysx/
    └── index.rst             ← stub flagged as highly experimental; tracking issue #5634
```

**Highlights**

- The Newton subdir moves wholesale out of `experimental-features/` via
`git mv`; framing changes from "experimental feature branch" to "beta
backend." The Experimental Features toctree now contains only
`bleeding-edge`.
- Per-solver Newton pages (`mjwarp-solver`, `kamino-solver`) replace the
old `solver-transitioning` / `using-kamino` files, matching #876's
"sub-sections for the Newton solvers" ask.
- New PhysX page set written from `isaaclab_physx.physics.PhysxCfg`,
mirroring the Newton structure.
- OvPhysX stub references the full in-flight PR set (#5421, #5422,
#5426, #5459, #5570, #5589) and is gated by a follow-up issue (#5634)
for expansion after those land.
- `solver-comparison.rst` covers friction, contact pipeline,
restitution, stabilization, convergence, articulation coordinates,
substepping, and GPU buffers across PhysX TGS, Newton MJWarp, and Newton
Kamino. Each cell points at the concrete config attribute that controls
the behavior, with a porting checklist at the end.
- Newton's `supported-features.rst` list refreshed against `develop`'s
actual `newton_mjwarp` coverage (adds Shadow Hand, Shadow Hand Over,
cabinet, dexsuite, rough-terrain locomotion). Replaces the bit-rotting
bullet list with a discovery recipe (`grep -rln newton_mjwarp
source/isaaclab_tasks/`).
- Cross-references updated in `docs/index.rst`,
`core-concepts/index.rst`, `multi_backend_architecture.rst`,
`features/visualization.rst`, and
`overview/reinforcement-learning/rl_existing_scripts.rst`.

Fixes isaac-sim/IsaacLab-Internal#876

## Type of change

- Documentation update

## Screenshots

N/A — docs-only restructure. New page tree visible from the
table-of-contents in `core-concepts/`.

## Checklist

- [x] I have read and understood the [contribution
guidelines](https://isaac-sim.github.io/IsaacLab/main/source/refs/contributing.html)
- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works *(N/A — docs-only)*
- [ ] I have added a changelog fragment under
`source/<pkg>/changelog.d/` for every touched package *(N/A — docs-only;
matches precedent of #5512 and 4aeb4d6 which shipped without
fragments)*
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there