Working notes for Open-Source Humanoid Robotics Landscape (Oct 2026), compiled Oct 2, 2026. Not fact-checked line by line: where these notes and the report disagree, trust the report. See README.md.

Open-source humanoid robotics, simulation slice: simulators, physics engines, training frameworks and environments (status as of 2026-10-02)

How to read this report

Source tags

• [GH]: GitHub repo page fetched today with WebFetch.
• [GI]: GitHits registry/repo index. This covers PyPI metadata plus the linked repo's stars/forks; download counts were refreshed 2026-10-02.
• [GI-file]: a repository file read through the GitHits index (a commit-pinned snapshot).
• [web]: another web page fetched today.
• [headline]: a search-result title only; the page was not opened.
• "(self-reported)": the number was published by the project's own team.

Fetch limitations

• The fetch proxy refused these pages with HTTP 429 (rate limited). I did not retry them:
  • github.com/google-deepmind/mujoco
  • github.com/google-deepmind/mujoco/releases
  • github.com/google-deepmind/mujoco_warp
  • github.com/google-deepmind/mujoco_menagerie
  • github.com/google-deepmind/mujoco_playground
  • github.com/Genesis-Embodied-AI/genesis-world
  • pypi.org/project/mujoco, pypi.org/project/mujoco-warp, pypi.org/project/newton
  • NVIDIA blog post "Newton adds contact-rich manipulation and locomotion…"
  • Dataconomy article on Newton 1.0
  • Stone Tao's Substack post on Genesis
• Because github.com was throttled, I took star counts from GitHits where possible.
• Star counts for Genesis, MuJoCo Menagerie and MuJoCo Playground could not be fetched today.
• This session's shared WebSearch quota (200 calls) ran out partway through.

0. The 2025–2026 consolidation and what it means

1. Newton became the shared GPU physics core.

• Newton is a Linux Foundation project under Apache-2.0, started by NVIDIA, Google DeepMind and Disney Research.
• Releases: first PyPI build 0.1.3 on 2025-09-26, 1.0.0 on 2026-03-10, then monthly minor releases up to 1.6.0 on 2026-09-10 [GI].
• Its primary backend is MuJoCo Warp. MuJoCo Warp was "officially released" in MuJoCo 3.5.0 (2026-02-12) and its version numbers now track MuJoCo's (3.14.0, 2026-09-22) [GI-file].
• Newton's Technical Steering Committee includes:
  • Yuval Tassa (Google DeepMind)
  • Miles Macklin (NVIDIA)
  • Vassilios Tsounis and Moritz Baecher (Disney Research)
  • Drake developers Michael Sherman and Joe Masterjohn (Toyota Research Institute)

2. NVIDIA's stack no longer requires Isaac Sim ("kit-less").

• Isaac Lab 3.0 went from beta on 2026-03-17 to Early Access on 2026-09-16 [GH]. It supports several physics backends: PhysX, Newton/MuJoCo Warp, and OVPhysX.
• In Newton mode it runs without Isaac Sim [GI-file].
• The PhysX SDK and the Omniverse PhysX extensions are BSD-3 on GitHub. A standalone ovphysx pip wheel exists (0.6.3, 2026-09-16) [GI].
• Isaac Sim's source has been Apache-2.0 on GitHub since 5.0 (GA tag 2025-08-08). It still needs the proprietary Omniverse Kit SDK and NVIDIA assets [GI-file].

3. The MuJoCo ecosystem collapsed onto MJX and MuJoCo Warp.

• Brax's own physics is deprecated; only brax/training is maintained [GI-file].
• MuJoCo Playground can run on either MJX or MuJoCo Warp.
• mjlab puts Isaac Lab's manager-based API on top of MuJoCo Warp.
• MJX itself can call MuJoCo Warp as a backend (since 3.4.0).

4. One VC-backed independent remains: Genesis World.

• Genesis World 1.0 shipped on PyPI on 2026-05-27 [GI].
• It is backed by Genesis AI ($105M seed, July 2025) [web].
• It runs on CUDA, ROCm, Metal and Vulkan via its own compiler, Quadrants, a June-2025 fork of Taichi.

5. Several platforms were retired or moved to legacy.

• Habitat: Meta stopped active development beyond v0.3.4.
• Isaac Gym: NVIDIA calls it "legacy … no longer supported."
• legged_gym: migrated to Isaac Lab in 2024.
• Brax: physics deprecated.
• Cosmos-Predict2.5: limited maintenance since Cosmos 3.

6. Renderers are converging on 3D Gaussian splats.

• Isaac Sim 6.0 NuRec, the MuJoCo Warp batch renderer, Newton's Gaussian BVH and Genesis's Nyx renderer all render splats.
• So do GaussGym, DISCOVERSE and GS-Playground.

7. Asset formats are being pushed toward OpenUSD, but MJCF still dominates the MuJoCo family.

• Newton imports USD and is aligning with the AOUSD deformable-schema proposals.
• The newton-physics org publishes mujoco-usd-converter and urdf-usd-converter, which are still small (75 and 72 stars) [GI].

What this means for a simulation, environment or data startup

• Rigid and articulated physics is becoming a free, well-funded commodity. Building another solver is a poor bet.
• Defensible value is in the layers above the solver:
  • sim-ready assets supplied in both USD and MJCF, tuned per solver;
  • procedurally varied scenes and task suites;
  • automated demonstrations;
  • actuator and system-ID calibration (MuJoCo shipped a sysID toolbox and actuator delays in 3.5.0);
  • evaluation infrastructure that shows simulation results predict real-world results;
  • real-to-sim pipelines that produce collision- and physics-ready digital twins, not just splats.
• Target the backend-agnostic layers: Isaac Lab 3 multi-backend, Newton and MuJoCo Warp.
• Watch the licence traps:
  • the Omniverse Kit SDK;
  • cuRobo, which is proprietary and required by Isaac Lab Mimic;
  • Omniverse-licensed pip wheels.

1. Physics engines and core simulators

MuJoCo (with MJX): reference engine for contact-rich robotics

• Status: ACTIVE.
  • 3.14.0 released 2026-09-22.
  • Monthly minor releases since 3.5.0 (2026-02-12).
  • Last push 2026-10-01 [GI].
• Who: Google DeepMind (Yuval Tassa and team).
• Links:
  • GitHub google-deepmind/mujoco
  • mujoco.org
  • mujoco.readthedocs.io
• GitHub stats: 15k stars, 1.7k forks, 309 open issues [GI]. Latest release 3.14.0 (2026-09-22).
• License: Apache-2.0.
• What it is:
  • Generalized-coordinate dynamics with a convex soft-contact solver (pyramidal or elliptic friction).
  • Supports tendons, muscles, "flex" deformables and a rich set of sensors.
  • MJCF format plus the mjSpec model-editing API.
  • Python bindings, a WebAssembly build (wasm/ in the repo), and an in-browser viewer at live.mujoco.org.
  • MJX is a JAX port (vmap/pmap on GPU or TPU). Since 3.4.0, MJX's pmap also works with MuJoCo Warp.
• 2025–26 changes [GI-file changelog]:
  • 3.4.0 (2025-12-05): sleeping islands (preliminary) and quadratic flex.
  • 3.5.0 (2026-02-12):
    • MuJoCo Warp officially released.
    • Python System Identification toolbox.
    • Actuator and sensor delays via history buffers.
    • Implicit integration for flex.
    • Rangefinder sensors attachable to cameras.
  • 3.14.0 (2026-09-22):
    • Experimental IPC mode for penetration-free (frictionless) flex contact.
    • Multi-input actuators (pid, dcmotor, orientation).
    • Archive resource providers for .mjz/.zip files.
• Adoption:
  • PyPI mujoco: 4.0M downloads/month [GI].
  • dm_control (4.7k stars) is still released in lockstep (1.0.47 on 2026-09-22).
  • It underpins Menagerie, Playground, mjlab, robosuite/RoboCasa, LocoMuJoCo, MyoSuite and the Gymnasium MuJoCo environments.
  • It is the usual "sim2sim" check before deploying Isaac Lab policies; for example, unitree_rl_lab goes Isaac Lab → MuJoCo → real G1 [GI-file].
• Benchmarks: CPU MuJoCo is tuned for per-step latency. The docs recommend MuJoCo Warp for throughput.
• Trade-offs:
  • Best accuracy and determinism, minimal dependencies, and real-time MPC on CPU.
  • Basic OpenGL rendering; no RTX-class sensors.
  • USD only through a converter.
• Sources:
  • github.com/google-deepmind/mujoco/blob/main/doc/changelog.rst and doc/mjwarp/index.rst [GI-file]
  • PyPI metadata [GI]

MuJoCo Warp (MJWarp): GPU MuJoCo for NVIDIA hardware

• Status: ACTIVE.
  • "Officially released" 2026-02-12.
  • PyPI releases: 0.0.1/0.0.2 (2026-01-08), then 3.5.0 (2026-02-13) through 3.14.0 (2026-09-22), at a monthly cadence [GI].
• Who: Google DeepMind and NVIDIA, "as part of the Newton project" (README). mjlab credits Erik Frey and Taylor Howell.
• Links:
  • google-deepmind/mujoco_warp
  • docs at mujoco.readthedocs.io/en/latest/mjwarp
• GitHub stats: 1.3k stars, 194 forks [GI]. 383k downloads/month [GI].
• License: Apache-2.0.
• What it is:
  • The MuJoCo pipeline rewritten in NVIDIA Warp; usable as a drop-in replacement for MuJoCo.
  • A ray-traced batch renderer supporting meshes, textures, heightfields, flex objects, Gaussian splats, per-camera intrinsics, lighting and shadows.
  • Reachable from three ecosystems: JAX (via MJX), PyTorch (via Newton/Isaac Lab), and mjlab.
  • Not yet supported:
    • the IMPLICITFAST midpoint feature;
    • the PGS and noslip solvers;
    • plugin actuators and sensors.
  • Flex is experimental, and Warp-based differentiability is "not yet available" (issue #500) [GI-file README].
• Adoption:
  • Primary backend of Newton.
  • Isaac Lab 3.0's Newton backend.
  • mjlab.
  • MuJoCo Playground (--impl warp).
  • Amazon FAR's holosoma.
  • RoboVerse (via mjlab).
• Benchmarks:
  • Nightly benchmarks cover G1 flat and heightfield, MyoArm, ALOHA (clutter, pot, SDF, cloth), three humanoids and cloth. The page is JavaScript-rendered and I could not extract numbers from it.
  • Renderer claim: "millions of frames per second" (self-reported; no conditions given).
  • The best concrete public numbers are in Isaac Lab's benchmark data (see the Isaac Lab entry).
• Trade-offs (official docs):
  • "Scales better than MJX on nearly every workload."
  • A single step is slower than CPU MuJoCo.
  • It scales "not as well as MuJoCo for single large kinematic trees … beyond ~60 DoFs remains an active priority."
  • That matters for humanoids with dexterous hands: a 29-DoF G1 plus two 16–24-DoF hands is well over 60 DoF.
  • Fast simulation requires an NVIDIA GPU; CPU works for debugging.
• Sources:
  • github.com/google-deepmind/mujoco_warp/blob/main/README.md [GI-file]
  • doc/mjwarp/index.rst [GI-file]
  • google-deepmind.github.io/mujoco_warp/nightly/ [web, page had no extractable data]

MuJoCo Menagerie: curated MJCF robot models

• Status: likely ACTIVE.
  • The indexed README includes recent hands and arms (Sharpa Wave, Tetheria Aero Hand Open, Franka FR3 v2, Trossen WXAI, i2rt YAM).
  • Newton 1.6 (Sep 2026) re-converted "eight structured USD menagerie robots."
  • Commit dates are unverified (GitHub page 429).
• Who: Google DeepMind, with vendor and community contributions.
• GitHub stats: not fetched today.
• License: set per model (Apache-2.0, BSD-3, BSD-2, MIT, BSD-3-Clear).
• What it is: the gallery lists 71 models [GI-file]:
  • 11 humanoids:
    • Unitree H1 (19 DoF) and G1 (29)
    • Robotis OP3 (20)
    • PAL TALOS (44)
    • Booster T1 (23)
    • ToddlerBot 2XC and 2XM (44 each)
    • PNDbotics Adam_lite (25)
    • Apptronik Apollo (32)
    • Berkeley Humanoid (12)
    • Fourier N1 (23)
  • Dexterous hands:
    • Allegro V3 (16)
    • Shadow E3M5 (24)
    • Shadow DEX-EE (12)
    • LEAP (16)
    • Sharpa Wave (22)
    • Tetheria Aero Hand Open (16)
  • Grippers: Robotiq 2F-85, UMI.
  • Other: about 25 arms, mobile manipulators (Stretch, TIAGo, RBY1, TidyBot), quadrupeds, MS-Human-700 and flybody.
• Adoption: Playground downloads Menagerie assets automatically. Newton and Isaac Lab Newton presets use USD conversions of it.
• Trade-offs: high-quality, but small and MJCF-first. The licence differs per model, which matters if you redistribute.
• Sources: github.com/google-deepmind/mujoco_menagerie/blob/main/README.md [GI-file].

MuJoCo Playground: GPU robot-learning environments with sim-to-real recipes

• Status: on the ACTIVE/SLOWING boundary. PyPI playground 0.1.0 (2026-01-08) and 0.2.0 (2026-03-16) [GI]; commit dates unverified.
• Who: Google DeepMind and UC Berkeley (Zakka, Tabanpour, Liao, … Sreenath, Sferrazza, Tassa, Abbeel).
• Paper: arXiv 2502.08844 (2025-02-12), RSS 2025.
• GitHub stats: not fetched (429).
• License: Apache-2.0.
• What it is:
  • dm_control classic tasks.
  • Quadruped and biped/humanoid locomotion.
  • Non-prehensile and dexterous manipulation.
  • Vision tasks via the MuJoCo Warp batch renderer.
  • Trains with Brax PPO (JAX) or RSL-RL; switch to MuJoCo Warp with --impl warp.
• Benchmarks and sim2real (paper abstract): "Train policies in minutes on a single GPU." Zero-shot sim-to-real from both state and pixels on quadrupeds, humanoids, dexterous hands and arms.
• Pain point: the README warns that JAX defaults to TF32 on Ampere/Ada GPUs, which hurts RL reproducibility. Set JAX_DEFAULT_MATMUL_PRECISION=highest.
• Trade-offs: fastest route to locomotion or hand sim2real in JAX. mjlab (PyTorch) and Isaac Lab (RTX sensors, USD) suit other stacks.
• Sources:
  • arxiv.org/abs/2502.08844 [web]
  • PyPI playground description [GI]

Newton: Linux Foundation GPU physics engine for robotics (Warp-based)

• Status: ACTIVE.
  • 0.1.3 (2025-09-26), 0.2.0 (2026-02-25), 1.0.0 (2026-03-10).
  • 1.1.0 (Apr 13), 1.2.0 (May 12), 1.3.0 (Jun 11), 1.4.0 (Jul 16), 1.5.0 (Aug 11).
  • 1.6.0 (2026-09-10) [GI-file CHANGELOG].
  • The Linux Foundation announced Newton 1.0 general availability around GTC in March 2026 [headline].
• Who:
  • Started by Disney Research, Google DeepMind and NVIDIA.
  • Maintainers: Miles Macklin, Saran Tunyasuvunakool, Vassilios Tsounis, Eric Heiden, Jan Carius, Eric Shi, @nvtw and Alain Denzler.
  • TSC: Macklin; Tsounis (co-chair); Michael Sherman; Joe Masterjohn; Yuval Tassa; Moritz Baecher; Louis Lian; Mohammad Mohajerani (co-chair); Frank Chen [GI-file newton-governance/CONTRIBUTORS.md].
• Links:
  • newton-physics/newton
  • newton-physics.github.io/newton
• GitHub stats: 5.6k stars, 671 forks [GH]. Latest release 1.6.0 (2026-09-10).
• License: Apache-2.0 for code, CC-BY-4.0 for docs.
• What it is: generalizes Warp's deprecated warp.sim. One Model/State/Control API with interchangeable solvers [GI-file docs/solvers]:
  • Generalized coordinates: SolverMuJoCo (MuJoCo Warp) and SolverFeatherstone.
  • Maximal coordinates: SolverSemiImplicit, SolverXPBD, and SolverKamino (experimental; kinematic loops, hard frictional contact).
  • SolverVBD (experimental; cloth, soft and rigid bodies in one solver).
  • SolverStyle3D (cloth).
  • SolverImplicitMPM (particles and granular).
• Features:
  • SDF and mesh collision.
  • Hydroelastic contact (experimental).
  • Speculative contacts (1.6).
  • Gaussian-splat BVH.
  • Tiled ray-traced camera sensor.
  • Import from OpenUSD (including AOUSD deformable proposals), MJCF and URDF.
  • Differential-IK and operational-space controllers; DC-motor actuator models.
• Platforms: Python 3.10+, Linux (x86-64/aarch64) and Windows. Requires an NVIDIA GPU (Maxwell or newer, driver 545+). macOS runs CPU only.
• Adoption:
  • Isaac Lab 3.0 Newton backend.
  • ProtoMotions 3 (pinned to Newton 1.0) [GI-file].
  • The Linux Foundation's 1.0 announcement lists "stable articulated mechanism simulation, hydroelastic contact modeling, deformable body simulation (cables, cloth, rubber)…" [headline: x.com/linuxfoundation].
• Benchmarks: see the Isaac Lab table: Newton/MuJoCo Warp delivers about 1.5–2.1× PhysX training throughput with less VRAM (NVIDIA-run). Third-party claims such as "475× faster" (byteiota) are unverified.
• Trade-offs:
  • The broadest multi-solver open engine, with backing from industry and the Linux Foundation.
  • The API is changing quickly; 1.6 deprecates cable APIs and changes USD deformable defaults, for example.
  • Speed requires NVIDIA hardware.
  • Several solvers are still experimental.
• Sources:
  • github.com/newton-physics/newton [GH]
  • README.md, CHANGELOG.md and docs/solvers/index.rst [GI-file]
  • newton-governance CONTRIBUTORS.md and CONTRIBUTING.md [GI-file]

NVIDIA Isaac Sim (with PhysX/OVPhysX): Omniverse/USD robot simulator with RTX sensors

• Status: ACTIVE.
  • GitHub tags [GH]:
    • v5.0.0 GA (2025-08-08)
    • v5.1.0 GA (2025-10-21)
    • v6.0.0-dev (2025-12-19)
    • v6.0.0-dev2 (2026-03-16, GTC'26 early developer release)
    • v6.0.0 GA (2026-06-04)
    • v6.0.1 (2026-06-22)
  • 6.1:
    • PyPI isaacsim 6.1.0.0 (2026-09-09) [GI].
    • Forum post "Isaac Sim 6.1 General Availability" [headline].
    • The repo VERSION file read 6.1.0-rc.26 when indexed.
    • An open issue complains the 6.1.0 release notes are missing [headline].
• Who: NVIDIA.
• GitHub stats: isaac-sim/IsaacSim ~4.0k stars, 534 forks [GH]. PhysX repo NVIDIA-Omniverse/PhysX: 4.7k stars, 671 forks [GI].
• License: partially open.
  • The repo code is Apache-2.0.
  • Building or using it "requires additional components licensed under other terms … Omniverse Kit SDK, as well as 3D models and textures" (the Isaac Sim Additional Software and Materials License) [GI-file LICENSE].
  • PyPI metadata for the isaacsim and isaaclab wheels says "NVIDIA Proprietary Software" [GI].
  • PhysX SDK and Omni PhysX extensions are BSD-3. The ovphysx wheel's license field is "LicenseRef-NVIDIA-Omniverse" [GI].
• What it is:
  • Imports URDF, MJCF and CAD; native USD.
  • GPU PhysX; RTX multi-sensor rendering.
  • Synthetic data generation, ROS 2 bridge, digital twins.
  • 6.0 added NuRec 3D Gaussian splat scenes, GPU nested rigid bodies and expanded XR [web].
  • Requirements: Python 3.12; Ubuntu 22.04/24.04 (GCC 11 only), Windows 11, or aarch64 (DGX Spark).
  • Minimum GPU: RTX 4080 (workstation) or A40 (datacenter).
  • The build needs internet access to Kit extension servers [GI-file README].
• Adoption: BEHAVIOR-1K/OmniGibson, Isaac Lab, robosuite (photoreal rendering option), and Arena-based benchmarks.
• Trade-offs:
  • Highest-fidelity sensors and USD/Omniverse integration.
  • Heavy installation, high GPU floor, proprietary Kit dependency, and frequent breaking upgrades.
• Sources:
  • github.com/isaac-sim/IsaacSim and /releases [GH]
  • README.md, LICENSE and VERSION [GI-file]
  • NVIDIA-Omniverse/PhysX README [GI-file]
  • radiancefields.com article on Isaac Sim 6.0 NuRec [web]

Isaac Lab (including 3.0): NVIDIA's open robot-learning framework

• Status: ACTIVE [GH releases]:
  • v2.3.1 (2025-12-04)
  • v2.3.2 (2026-02-02)
  • v3.0.0-beta (2026-03-17)
  • v3.0.0-beta2 (2026-06-17)
  • beta2.patch1 (2026-07-02)
  • v3.0.0-EA (2026-09-16), which targets Isaac Sim 6.1
  • PyPI isaaclab 2.3.2.post1 (2026-02-11) [GI]
• Who: NVIDIA with many partners. The tech report (arXiv 2511.04831, 2025-11-06) has a long author list including ETH Zurich (Hutter), UT Austin (Zhu) and others.
• GitHub stats: 8.2k stars, 3.9k forks [GH].
• License:
  • BSD-3 for the framework; Apache-2.0 for isaaclab_mimic.
  • Full workflows (PhysX, RTX, ROS, URDF/MJCF importers) need Isaac Sim's proprietary components; kit-less Newton workflows do not.
  • isaaclab_mimic requires cuRobo, which is proprietary [GI-file README].
• What it is: a manager-based and direct RL/IL framework with 16+ robots and 30+ environments, including:
  • G1, H1 and Cassie locomotion;
  • Shadow-hand cube reorientation;
  • Franka and UR10 reach.
• 3.0 architecture [GI-file release notes]:
  • Factory-based multi-backend physics: isaaclab_physx (default) and isaaclab_newton, which is powered by MuJoCo Warp and supports the MuJoCo Warp, XPBD and Featherstone solvers with CUDA graphs. OVPhysX is experimental.
  • Pluggable renderers: Isaac RTX (needs Isaac Sim), OVRTX (kit-less RTX) and Newton Warp (kit-less).
  • Pluggable visualizers and a camera image-signal-processing pipeline (PPISP).
  • Isaac Capture teleop record/replay and policy export.
• Adoption:
  • unitree_rl_lab (Isaac Lab 2.3 / Isaac Sim 5.1; Go2, H1, G1-29).
  • BeyondMimic (Isaac Lab 2.1).
  • holosoma (Isaac Sim path).
  • RoboTwin (Arena branch).
  • The 3.9k forks suggest heavy downstream customization.
• Benchmarks: from NVIDIA's in-repo environment-performance-develop.csv:
  • Setup: RTX PRO 6000 Blackwell Server, 8,192 environments, RSL-RL training.
  • Metric: mean total frames per second (FPS), end to end.
  • Run dates: 2026-09-09, or 2026-08-28 where marked †.

• Caveats: NVIDIA ran these itself. Rows are flagged "dirty working tree reported." Newton rows are often flagged "coefficient of variation >25%." Contact parameters are not identical across backends.
• A live dashboard is at nvidia.github.io/omniperf.
• Older ManiSkill comparison (self-reported, Isaac Lab v1.2.0, RTX 4090, CartPole with 640×480 RGB, 128 environments): Isaac Lab 4,556 FPS using 15.2 GB, versus ManiSkill 10,144 FPS using 3.7 GB.
• Trade-offs:
  • Default choice for humanoid sim2real; the richest sensors and assets; now able to switch backends.
  • 3.0 is still EA/beta with breaking changes.
  • Licensing is mixed (Kit, cuRobo).
• Sources:
  • github.com/isaac-sim/IsaacLab and /releases [GH]
  • README.md, docs/source/refs/release_notes.rst and docs/source/_static/benchmarks/environment-performance-develop.csv [GI-file]
  • arxiv.org/abs/2511.04831 [web]

Isaac Lab-Arena: composable benchmark authoring and policy evaluation

• Status: ACTIVE (alpha). README v0.3 alpha targets Isaac Sim 6.0 / Isaac Lab 3.0, with the warning "Do not use this in production" [GI-file].
• Who: NVIDIA.
• GitHub stats: 557 stars, 102 forks [GH].
• License: Apache-2.0.
• What it is:
  • Environments are composed from a scene, an embodiment and a task.
  • Objects are placed by relation ("on", "next to").
  • Atomic skills chain into long-horizon tasks.
  • Agentic environment generation (experimental): a natural-language description becomes a specification, matching SimReady USD assets are found, and a family of environments is built.
  • Perturbation sweeps over lighting, cameras and mass.
  • Thousands of heterogeneous environments per GPU; multi-node runs via OSMO.
  • Policy client-server interface for GR00T and π0.5.
  • Subtask predicates and sensitivity analysis.
• Adoption: RoboTwin 2.0 maintains an IsaacLab-Arena branch.
• Trade-offs: directly addresses scene and task generation and evaluation at scale, the same space a startup would target. NVIDIA-stack only and immature.
• Sources:
  • github.com/isaac-sim/IsaacLab-Arena [GH]
  • README.md [GI-file]

mjlab: Isaac Lab's API on MuJoCo Warp

• Status: ACTIVE. 1.6.0 (2026-08-09) bumps MuJoCo/MuJoCo Warp to 3.11; last push 2026-09-23 [GI].
• Who: Kevin Zakka, Qiayuan Liao, Brent Yi, Louis Le Lay, Koushil Sreenath and Pieter Abbeel. Paper arXiv 2601.22074 (2026-01-29).
• GitHub stats: 3.1k stars, 538 forks; 54k downloads/month [GI].
• License: Apache-2.0, plus BSD-3 for utilities forked from Isaac Lab.
• What it is:
  • Isaac Lab's manager-based environment API on MuJoCo Warp, installable with one command.
  • Direct access to native MuJoCo data structures.
  • Reference tasks: G1 velocity tracking, motion imitation (including a BeyondMimic reproduction) and manipulation.
  • Multi-GPU training via torchrunx; nightly benchmarks.
• Benchmarks: "on par or faster than Isaac Lab" (self-reported FAQ; no numbers).
• Pain points [GI-file FAQ and releases]:
  • The FAQ attributes NaN crashes partly to MuJoCo Warp "still in beta."
  • 1.5.3 fixed "CUDA 700 crashes from mass domain randomization on certain GPU architectures."
  • 1.5.2 fixed multi-environment domain-randomization crashes.
  • Recommended GPUs: RTX 40-series or newer, L40S, H100.
• Trade-offs: a lightweight PyTorch stack with no Omniverse. It lacks RTX sensors and USD asset tooling.
• Sources:
  • github.com/mujocolab/mjlab README.md and docs/source/faq.rst [GI-file]
  • arxiv.org/abs/2601.22074 [web]

Genesis World: multiphysics simulator from Genesis AI

• Status: ACTIVE.
  • 1.0.0 (2026-05-27).
  • Roughly weekly releases since then, up to 1.4.3 (2026-09-30) [GI].
  • The repo was renamed to genesis-world.
• Who:
  • Started as an academic project in December 2024; now "officially supported by Genesis AI."
  • Founders: Zhou Xian (CEO) and Théophile Gervet (President).
  • $105M seed (July 2025) led by Eclipse and Khosla Ventures, with Bpifrance, HSG, Eric Schmidt, Xavier Niel, Daniela Rus and Vladlen Koltun.
  • About 60 staff in Paris, California and London.
  • The company has gone "full stack": its own hand (with Wuji Tech), a data glove and the GENE-26.5 model. Zhou says simulation mainly speeds up evaluation [web TechCrunch 2026-05-06].
  • Media in 2026 reported talks to raise about $500M at about a $3B valuation [headline, unverified].
• Links:
  • Genesis-Embodied-AI/genesis-world
  • genesis-world.readthedocs.io
  • Quadrants (219 stars) and Nyx renderer (nyx-for-genesis, 138 stars) [GI]
• GitHub stats: stars and forks not fetched (GitHub page 429).
• License: Apache-2.0.
• What it is:
  • One scene and state shared by rigid, FEM, MPM, SPH, PBD, IPC (libuipc) and SAP coupling.
  • Three renderers: Nyx (with 3D Gaussian splats), Luisa ray tracing and Pyrender.
  • Quadrants compiler targets CUDA, AMD ROCm, Apple Metal, Vulkan, x86 and ARM64.
  • Imports URDF, MJCF, OBJ, GLB and USD.
  • Sensors include tactile, IMU, lidar, depth and contact force.
  • G1 and dexterous-hand benchmarks run in CI.
• Benchmarks and the 2024 controversy:
  • The original README (v0.2.1/v0.3.0) claimed "over 43 million FPS when simulating a Franka robotic arm with a single RTX 4090 (430,000× faster than real-time)" [GI-file].
  • In December 2024, ManiSkill lead Stone Tao published "How fast is the new hyped Genesis simulator?" It argued the figure came from an unrepresentative, near-trivial setup and that Genesis was not faster on comparable manipulation workloads. I could not re-open the post today (429), so its specifics are not re-verified here.
  • On 2025-01-09 Genesis published a benchmarking report with test scripts (zhouxian/genesis-speed-benchmark, which links to a Notion page I could not read).
  • The current README drops the 43M-FPS claim. Contributors must now show at least +5% on the CI benchmarks in tests/benchmarks.
  • Self-reported release notes:
    • 1.0 made the rigid solver "up to 35% faster for contact-rich scenes with ~64 DoFs."
    • A later 1.x release runs "100 entities / 1000 geometries … real-time at 120 FPS" on CPU.
    • 1.4.2 notes that Signorini contact is still "experimental due to convergence issue."
  • I found no independent head-to-head benchmark of Genesis 1.x.
• Trade-offs:
  • The widest multiphysics and the only cross-vendor GPU option, plus tactile sensors.
  • Credibility on speed claims was damaged in 2024; the API changes quickly; the ecosystem is smaller than NVIDIA's or MuJoCo's.
• Sources:
  • README.md, RELEASE.md and README at v0.2.1/v0.3.0 [GI-file]
  • techcrunch.com/2026/05/06/… [web]
  • Substack post [headline only; fetch refused]

ManiSkill3 / SAPIEN: GPU-parallel manipulation simulation and rendering

• Status:
  • ManiSkill: ACTIVE (3.0.1 released 2026-04-21; last push 2026-08-04) [GI].
  • SAPIEN: SLOWING (3.0.3 released 2026-03-10) [GH][GI].
  • The README now points to the github.com/mani-skill org.
• Who: UCSD SU Lab (Hao Su) and Hillbot. Paper arXiv 2410.00425 (Stone Tao, Fanbo Xiang, Arth Shukla, Yuzhe Qin, …), RSS 2025.
• GitHub stats: ManiSkill 3.3k stars, 550 forks [GI]; SAPIEN 793 stars, 77 forks [GH].
• License: ManiSkill Apache-2.0; SAPIEN MIT.
• What it is:
  • PhysX-5 GPU simulation with SAPIEN's Vulkan renderer (rasterized; ray tracing is not parallelized).
  • Heterogeneous parallel scenes: a different scene in every parallel environment.
  • Task suites: table-top, mobile manipulation, humanoid (Unitree G1, MuJoCo humanoid; "still adding more"), dexterous.
  • Real-to-sim evaluation environments.
  • Baselines: PPO/SAC/TD-MPC2, BC/Diffusion Policy, and VLA models (Octo, RDT-1B, RT-x).
  • URDF and MJCF loaders; MJCF support is partial.
• Benchmarks (self-reported):
  • Rendering plus simulation "10–1000× faster with 2–3× less GPU memory."
  • "30,000+ FPS."
  • CartPole comparison: see the Isaac Lab entry.
• Downstream: RoboTwin 2.0 (2.8k stars); RoboVerse integration.
• Trade-offs:
  • Easiest pip installation and very efficient visual RL for manipulation.
  • GPU simulation is Linux-only (CPU only on Windows).
  • Thin humanoid coverage; small team.
• Sources:
  • github.com/haosulab/SAPIEN [GH]
  • ManiSkill README, docs/source/user_guide/additional_resources/performance_benchmarking.md, benchmark CSVs and custom_robots.md [GI-file]
  • arxiv.org/abs/2410.00425 [web]

Drake: model-based robotics toolbox with high-fidelity contact

• Status: ACTIVE.
  • Monthly releases; PyPI drake 1.55.0 (2026-07-15), 1.56.0 (2026-08-14), 1.57.0 (2026-09-10) [GI].
  • The GitHub page fetch reported v1.54.0 (June 12, 2026) as latest, which conflicts with PyPI; the PyPI dates are more recent.
• Who: Toyota Research Institute (Russ Tedrake; Sherman and Masterjohn, who also sit on Newton's TSC).
• GitHub stats: 4.1k stars, 1.4k forks [GH].
• License: BSD-3.
• What it is:
  • MultibodyPlant with hydroelastic contact and the SAP solver.
  • Parsers for URDF, SDFormat and (partially) MJCF.
  • Optimization and verification tools; CPU-based.
• Trade-offs:
  • Best for verifying manipulation and model-based control.
  • Not designed for massively parallel RL; small humanoid-RL footprint.
• Sources: github.com/RobotLocomotion/drake [GH]; PyPI [GI].

Gazebo (Harmonic, Ionic, Jetty): ROS-centric robot simulator

• Status: ACTIVE [web gazebosim.org/docs/all/releases]:
  • Jetty: LTS, September 2025, end of life May 2031. GitHub tag gz-sim10_10.0.0 dated 2025-10-14 [GH].
  • Ionic: end of life December 2026.
  • Harmonic: LTS until May 2029.
  • Fortress: LTS until May 2027.
  • Next release "M" planned for March 2027 (new cadence).
  • "Rotary" is a nightly rolling release.
• Who: Open Robotics / OSRF; the gz-sim maintainer address is at Intrinsic.
• GitHub stats: gz-sim 1.4k stars, 427 forks [GH].
• License: Apache-2.0.
• What it is:
  • Physics via gz-physics plugins: DART, Bullet, Bullet-Featherstone and TPE.
  • OGRE 2 rendering; SDFormat (URDF via conversion); ROS 2 integration.
• Trade-offs: standard for ROS system and integration testing and sensor simulation. Not GPU-parallel; rarely used for humanoid RL.
• Sources:
  • github.com/gazebosim/gz-sim [GH]
  • gz-sim and gz-physics READMEs [GI-file]
  • releases page [web]

Webots: desktop simulator for education and industry

• Status: SLOWING.
  • The last tagged release is R2025a (GitHub, 2025-02-04; changelog says 2025-01-31) [GH].
  • An unreleased R2025b changelog in the repo adds Ubuntu 26.04 support, which implies 2026 commits; I did not verify commit dates.
• Who: Cyberbotics.
• GitHub stats: 4.5k stars, 2k forks [GH].
• License: Apache-2.0.
• What it is: ODE-based physics, PROTO model format, URDF import, and many bundled robots, including humanoids such as the KHR-3HV.
• Trade-offs: easy to use and good for teaching. CPU-only and not suited to large-scale RL.
• Sources: github.com/cyberbotics/webots [GH]; docs/reference/changelog-r2025.md [GI-file].

Project Chrono: multiphysics engine for vehicles, terrain, FEA and granular materials

• Status: ACTIVE. 10.0.0 released 2026-03-27; 9.0.0 was 2024-05-20 [GI-file CHANGELOG].
• Who: University of Wisconsin–Madison SBEL and partners.
• GitHub stats: 3.1k stars, 638 forks [GH].
• License: BSD-3.
• What it is:
  • Multibody dynamics, FEA, DEM granular materials, fluid-structure interaction and vehicles.
  • Templates for ROS, FMI2 and vehicle co-simulation.
  • PyChrono via conda.
• Trade-offs: strong for deformable terrain and off-road vehicles. Niche for humanoids or GPU RL.
• Sources: github.com/projectchrono/chrono [GH]; CHANGELOG.md [GI-file].

PyBullet: legacy Python physics simulator

• Status: SLOWING, close to dormant. Last release pybullet 3.2.7 (2025-01-30); last push to bullet3 2025-10-22 [GI].
• Who: Erwin Coumans and the community.
• GitHub stats: bullet3 14k stars, 3.0k forks [GI].
• License: zlib.
• What it is: CPU rigid-body simulation with URDF, SDF and MJCF (partial) support. It still underpins older benchmarks (GenSim/Ravens) and Habitat.
• Trade-offs: use only for legacy reproduction.
• Sources: PyPI [GI].

Brax: JAX RL library (physics deprecated)

• Status: ACTIVE, but README: "Only brax/training is actively being maintained as of 0.13.0." It points users to MuJoCo Playground for environments and MJX/MuJoCo Warp for physics, and says Brax may become purely an RL library. Latest 0.14.2 (2026-03-15); last push 2026-09-29 [GI].
• GitHub stats: 3.2k stars, 356 forks [GI].
• License: Apache-2.0.
• Sources: google/brax README.md [GI-file].

Isaac Gym: deprecated GPU RL simulator

• Status: DISCONTINUED. NVIDIA: "This is legacy software. Developers may download and continue to use it, but it is no longer supported." It recommends Isaac Lab instead. Preview 4 is the final version [web].
• legged_gym announced its migration to Isaac Lab on 2024-01-09 [GI-file].
• Still used by holosoma, ProtoMotions, HumanoidVerse and GaussGym.
• License: proprietary NVIDIA preview license (not open source).
• Sources: developer.nvidia.com/isaac-gym [web]; legged_gym and IsaacGymEnvs READMEs [GI-file].

2. Benchmark and environment suites

RoboCasa and robosuite: MuJoCo-based household manipulation at scale

• Status: ACTIVE.
  • RoboCasa365 v1.0 (2026-02-18); leaderboard opened 2026-04-06; v1.0.1 (2026-05-12); per-frame subtask annotations added 2026-07-07 [GI-file].
  • robosuite 1.5.2 (2025-12-24); last push 2026-07-11 [GI].
• Who: UT Austin (Yuke Zhu's lab) and collaborators. RoboCasa365 paper: arXiv 2603.04356, ICLR 2026 [headline].
• GitHub stats: RoboCasa 1.5k stars, 222 forks [GH]; robosuite 2.6k stars, 777 forks [GI].
• License: MIT code; CC BY 4.0 assets and datasets. robosuite is MIT [GI-file].
• What it is:
  • RoboCasa365 has 365 tasks created "with the guidance of LLMs."
  • 2,500+ kitchen scenes and 3,200+ objects, including AI-generated objects.
  • 600+ hours of human demonstrations plus 1,600+ hours of robot data produced with automated trajectory tools.
  • Benchmarks Diffusion Policy, π and GR00T.
  • Assets are about a 10 GB download.
  • robosuite 1.5 (2024-10-31) added humanoids, composite and whole-body controllers, Apple Vision Pro teleoperation and Isaac Sim photoreal rendering.
• Adoption: NVIDIA released Cosmos-Predict2.5 "robot/policy" checkpoints for RoboCasa and LIBERO on 2026-02-23 [GI-file].
• Trade-offs: the richest open household content. CPU MuJoCo, so not GPU-parallel; dependencies are fragile ("use the master branch!").
• Sources: github.com/robocasa/robocasa [GH]; README.md [GI-file]; robosuite LICENSE and v1.5.0 notes [GI].

BEHAVIOR-1K / OmniGibson: 1,000-activity household benchmark on Isaac Sim

• Status: ACTIVE.
  • OmniGibson 3.9.3 in the monorepo; last push 2026-09-29 [GI].
  • A 2026 BEHAVIOR Challenge has demonstration datasets on Hugging Face [headline].
  • PyPI omnigibson is stale at 1.1.1 (2024).
• Who: Stanford (Li Fei-Fei, Jiajun Wu and colleagues).
• GitHub stats: 1.7k stars, 250 forks [GH].
• License: MIT for code.
• What it is: 1,000 everyday activities, Isaac Sim/PhysX with fluids, cloth and object states, BDDL task definitions, and LeRobot-format datasets.
• Trade-offs: the deepest long-horizon household semantics. Heavy (Isaac Sim) and slow compared with GPU RL simulators.
• Sources: github.com/StanfordVL/BEHAVIOR-1K [GH]; README and OmniGibson/setup.py [GI-file].

Habitat 3 (habitat-sim / habitat-lab): embodied AI navigation and rearrangement

• Status: DISCONTINUED by Meta. Both READMEs: "Beyond v0.3.4 this project is no longer receiving official active development or maintenance by Meta internal teams." Last PyPI publish and push 2026-05-07 [GI].
• GitHub stats: habitat-sim 3.8k stars, 548 forks, not archived [GH]; habitat-lab 3.1k stars, 691 forks [GI].
• License: MIT.
• What it is: Bullet physics; URDF robots; HM3D, HSSD and ReplicaCAD scenes; humanoid avatars.
• Benchmarks: "Fetch … in ReplicaCAD at over 8,000 SPS (1 RGBD 128×128 observation + 1/30 s dynamics per step)" (self-reported).
• Trade-offs: fast navigation research, but the platform risk is now high.
• Sources: github.com/facebookresearch/habitat-sim [GH]; READMEs [GI-file].

RoboVerse / MetaSim: one API across many simulators, plus a dataset

• Status: ACTIVE. 1.0.0b0 and MetaSim 0.2.0 released 2026-05-31 (CHANGELOG); design docs dated May 2026 [GI-file].
• Who: academic consortium (BIGAI among contributors). Paper arXiv 2504.18904, RSS 2025.
• GitHub stats: 1.9k stars, 167 forks [GH].
• License: Apache-2.0.
• What it is:
  • MetaSim handlers for Isaac Lab/Isaac Sim, Isaac Gym, MuJoCo, SAPIEN, PyBullet, Genesis and CoppeliaSim, plus Blender rendering.
  • Integrations with LIBERO, ManiSkill, mjlab, robosuite, RoboTwin and EmbodiedGen.
• Trade-offs: useful for migrating assets and tasks between simulators. Lowest-common-denominator abstractions.
• Sources: github.com/RoboVerseOrg/RoboVerse [GH]; README and CHANGELOG [GI-file].

Gymnasium-Robotics: Farama MuJoCo robotics environments

• Status: ACTIVE (maintenance). 1.4.2 (2026-01-02); last push 2026-09-07 [GI].
• GitHub stats: 1.9k stars, 150 forks.
• License: MIT.
• What it is: Fetch, Shadow Hand, Adroit, Franka Kitchen, mazes and MaMuJoCo. CPU-based; legacy-style benchmarks.
• Sources: PyPI [GI].

3. Procedural and generative environment tools

• Infinigen (Indoors / Articulated "Infinigen-Sim"): ACTIVE.
  • v2.0.0a1 (2026-07-15), "first alpha release of 2.0 overhaul."
  • Princeton VL; 7.1k stars, 608 forks; BSD-3 [GH].
  • Procedural Blender generation of nature scenes, indoor scenes (CVPR 2024) and sim-ready articulated assets (arXiv 2505.10755).
  • The most credible open procedural asset generator. Its outputs need physics tuning per simulator.
• Holodeck (allenai/Holodeck): likely DORMANT.
  • No releases; data version 2023_09_23; commit dates unverified.
  • 572 stars, 65 forks; Apache-2.0 [GH].
  • LLM-guided scene generation for AI2-THOR (CVPR 2024, arXiv 2312.09067). AI2-THOR's last PyPI release was 5.0.0, three years ago [GI].
• RoboGen (Genesis-Embodied-AI/RoboGen): likely DORMANT. 1.2k stars, 108 forks; Apache-2.0; no releases [GH]. Generative robot-agent task, scene and training pipeline.
• GenSim (liruiw/GenSim): likely DORMANT. 350 stars, 25 forks; MIT; no releases [GH]. GPT-4 writes PyBullet/Ravens task code (arXiv 2310.01361).
• Productized successors in 2026:
  • RoboCasa365's LLM-guided tasks and AI-generated objects.
  • Isaac Lab-Arena's agentic environment generation (experimental).
  • RoboVerse's EmbodiedGen integration.
  • The academic generators of 2023–24 mostly were not maintained.

4. Real-to-sim and digital twins (Gaussian splatting)

• Isaac Sim 6.0 NuRec [web radiancefields.com, 2026-06-07]:
  • Reconstructed real scenes load as USD and render through the Fabric Scene Delegate (multi-GPU, light interaction with meshes, MaterialX).
  • 3DGRUT exports USDZ.
  • Physics requires separately paired collision proxies.
• GaussGym (arXiv 2510.15352, 2025-10-17; Escontrela, Kerr, Allshire, Frey, Duan, Sferrazza, Abbeel):
  • Uses 3DGS as the renderer inside Isaac Gym.
  • ">100,000 simulation steps per second on consumer GPUs" (self-reported).
  • Scenes come from iPhone scans, GrandTour, ARKit and Veo-generated video.
  • Shows sim-to-real for locomotion from pixels. Repository stars not fetched.
• DISCOVERSE (TATP-233/DISCOVERSE): MuJoCo plus 3DGS for Real2Sim2Real; IROS 2025; arXiv 2507.21981; 518 stars, 65 forks; MIT [GH].
• GS-Playground (RSS 2026; Yufei Jia et al.): custom parallel physics engine plus 3DGS; "10⁴ FPS at 640×480" (self-reported) [web roboticsproceedings].
• Engine-native support:
  • MuJoCo Warp's batch renderer renders splats.
  • Newton exposes Gaussian.bvh.
  • Genesis Nyx has a 3DGS example.
• Gap: splats carry appearance only, not mass, friction or articulation. Turning them into physics-ready twins is still manual.

5. World models used as simulators

• NVIDIA Cosmos:
  • Cosmos 3 released May 2026 (Nano and Super; Edge 4B in July 2026).
  • One Mixture-of-Transformers model with two interfaces: a "Reasoner" (text and vision to text) and a "Generator" (text, vision, sound and action to vision, sound and action).
  • Includes action-conditioned forward dynamics and policies.
  • Code and models under OpenMDW-1.1 [GI-file].
  • Repo NVIDIA/Cosmos: 11.7k stars, 854 forks [GH].
  • NVIDIA claims first place among open models on several physical-AI benchmarks (self-reported) [web eWeek].
  • The Cosmos Coalition's founding members (per eWeek) include Agile Robots, Generalist, Skild AI and Runway.
  • Cosmos-Predict2.5 (2025-10-06; 2B/14B; robot action-conditioned models; DreamGen post-training) and Transfer2.5 are now in "limited maintenance" [GI-file].
• 1X World Model:
  • The production model shipped 2026-01-13 for the NEO robot. TechCrunch reports no information on weights or licence, so treat it as closed [web].
  • The open 1xgpt challenge repo (561 stars, 48 forks, Apache-2.0 [GH]) provides:
    • more than 100 hours of tokenized EVE robot video with actions;
    • a GENIE-style baseline and a MAGVIT2 tokenizer;
    • compression and sampling challenges ($10k each);
    • an evaluation (policy-ranking) challenge marked "upcoming" [GI-file].
  • Challenge technical report: arXiv 2510.07092 [headline].
• Closed comparators:
  • Veo world simulator for Gemini Robotics policy evaluation (arXiv 2512.10675, 2025-12-11): validated against "1,600+ real-world evaluations of eight Gemini Robotics policy checkpoints and five tasks." It predicts relative policy ranking in nominal and out-of-distribution conditions. No release stated [web].
  • Genie 3: "Project Genie" rolled out to Google AI Ultra users in the US around 2026-01-29 [headline]. No open weights.

6. Also notable (brief)

• NVIDIA Warp (NVIDIA/warp): ACTIVE (1.17.0, 2026-08-31); 6.9k stars; Apache-2.0; 1.0M downloads/month. warp.sim is deprecated in favor of Newton [GI].
• OVPhysX / PhysX (NVIDIA-Omniverse/PhysX): ACTIVE (ovphysx 0.6.3, 2026-09-16; PhysX SDK 5.11); 4.7k stars [GI].
• dm_control (google-deepmind/dm_control): ACTIVE (1.0.47, 2026-09-22); 4.7k stars [GI].
• LocoMuJoCo (robfiras/loco-mujoco): ACTIVE commits (push 2026-08-22; 1.0.0 released 2025-04-17); 1.4k stars; MIT; humanoid imitation benchmark [GI].
• MyoSuite: ACTIVE (2.12.2, about June 2026); musculoskeletal models on MuJoCo; Apache-2.0 [GI].
• Meta-World (Farama-Foundation/Metaworld): ACTIVE (3.1.1, about July 2026); 1.8k stars [GI].
• Gymnasium: ACTIVE (1.3.0); 12k stars; 3.6M downloads/month [GI].
• rsl_rl (leggedrobotics/rsl_rl): ACTIVE (rsl-rl-lib 5.5.1, about September 2026); 2.8k stars; 260k downloads/month; BSD-3 [GI].
• ProtoMotions 3 (NVlabs/ProtoMotions): ACTIVE.
  • 2.4k stars, 461 forks; Apache-2.0 [GH].
  • Backends: Newton 1.0, Isaac Lab 3.0, Isaac Gym and MuJoCo.
  • "AMASS 40+ hours within 12 hours on 4 A100s" (self-reported).
• holosoma (amazon-far/holosoma): 1.6k stars, 253 forks; Apache-2.0 [GH].
  • Backends: Isaac Gym, Isaac Sim, MuJoCo Warp and MuJoCo (inference only).
  • G1 and Booster T1; PPO and FastSAC.
• unitree_rl_lab: Isaac Lab 2.3 / Isaac Sim 5.1; Go2, H1 and G1-29; Apache-2.0 [GI-file]; stars not fetched.
• BeyondMimic (HybridRobotics/whole_body_tracking): Isaac Lab 2.1; MIT; arXiv 2508.08241; reproduced in mjlab [GI-file].
• HumanoidVerse (LeCAR-Lab/HumanoidVerse): status unverified. Pins Isaac Gym Preview 4, Isaac Sim 4.2 and Genesis 0.2.1; MIT [GI-file].
• legged_gym: DORMANT (migrated in 2024).
• RoboTwin 2.0 (RoboTwin-Platform/RoboTwin): ACTIVE (last update 2026-08-03); ICML 2026; 2.8k stars, 479 forks; MIT [GH].
• RoboHive (vikashplus/robohive): DORMANT (last PyPI release two years ago); 632 stars [GI].
• AI2-THOR: releases dormant (5.0.0, three years ago); 1.8k stars [GI].
• DART: ACTIVE (dartpy 6.19.4, about two months ago); 1.1k stars; BSD-2 [GI].
• newton-physics/mujoco-usd-converter: ACTIVE (0.6.1, 2026-09-29); 75 stars [GI].
• newton-physics/urdf-usd-converter: 0.3.3; 72 stars [GI].
• newton-physics/newton-usd-schemas: 0.5.0; 14 stars [GI].

7. Comparison table

8. Gaps and pain points (evidence)

1. Contact fidelity for dexterous humanoids is still immature on GPU.

• MuJoCo Warp's own docs say scaling past about 60 DoF in one connected mechanism "remains an active priority."
• MuJoCo Warp lacks PGS and noslip, and has no differentiability yet.
• Experimental contact features across engines:
  • Newton: Kamino, VBD and hydroelastic contact.
  • MuJoCo: IPC flex contact (frictionless).
  • Genesis: Signorini contact.
• mjlab's FAQ ties NaN crashes partly to MuJoCo Warp being in beta; 1.5.3 fixed GPU-architecture-specific crashes from mass randomization.
• Opportunity: validated contact parameter sets and system-ID services. MuJoCo 3.5 added a sysID toolbox and delay models, but there is no shared calibration data.

2. Benchmarks are mostly self-reported and hard to trust.

• The Genesis 43M-FPS dispute.
• ManiSkill compared itself with Isaac Lab v1.2 using a rasterizer against ray tracing.
• NVIDIA's own CSV flags "dirty working tree" and run-to-run variation above 25%.
• MuJoCo Warp's nightly dashboard is not machine-readable.
• Opportunity: a neutral benchmarking and certification service measuring throughput, fidelity and sim-to-real correlation.

3. Asset and scene creation is the bottleneck, and formats are fragmented.

• Menagerie has only 71 curated models, each with its own licence.
• The USD converters are new and tiny (about 72–75 stars each).
• Newton 1.6 changed USD deformable defaults (thickness, mass precedence) to align with AOUSD proposals that "are not yet registered."
• ManiSkill notes "not all MJCF properties are supported."
• RoboCasa365's 2,500 scenes and 3,200 objects (a 10 GB download) is the largest open household set.
• The research-era generators (Holodeck, RoboGen, GenSim) are dormant. Arena's agentic generation is experimental.
• Opportunity: validated sim-ready assets in both USD and MJCF with articulation, collision and physics parameters, plus a procedural scene service.

4. Real-to-sim produces appearance, not physics.

• NuRec needs separate collision proxies.
• GaussGym, DISCOVERSE and GS-Playground render splats over hand-built physics.
• Opportunity: automated splat-to-physics twins with segmentation, articulation inference and mass/friction estimation.

5. Licensing and lock-in.

• Isaac Sim needs the proprietary Kit SDK and assets.
• Isaac Lab Mimic needs cuRobo, which is proprietary.
• The isaacsim/isaaclab pip wheels are labelled "NVIDIA Proprietary Software"; the ovphysx wheel carries an Omniverse licence.
• MuJoCo Warp and Newton need NVIDIA GPUs for speed (Genesis is the cross-vendor exception).
• Isaac Sim requires at least an RTX 4080 or A40.

6. Platforms keep churning.

• Habitat dropped by Meta; Isaac Gym legacy; Brax physics deprecated; Cosmos-Predict2.5 sidelined.
• Repositories moved: ManiSkill to the mani-skill org, Genesis renamed to genesis-world, RoboTwin migrated.
• Isaac Lab 3.0 is a breaking re-architecture.
• Newton deprecates APIs every minor release.
• Users bear high maintenance costs, which favours adapters and backend-agnostic environment layers.

7. Evaluation is the stated bottleneck.

• Genesis AI's CEO: "the real bottleneck … is evaluation."
• Responses so far: Isaac Lab-Arena, the RoboCasa365 and RoboTwin leaderboards, the BEHAVIOR Challenge, and GDM's Veo simulator validated on 1,600+ real trials.
• Gap: no open, standardized method for measuring how well simulation results correlate with real-world results.

8. Reproducibility pitfalls.

• Playground's TF32 warning for JAX on Ampere/Ada GPUs.
• MuJoCo's IPC mode is not captured by mj_getState, so exact replay is not supported.
• Isaac Sim builds only with GCC 11.

9. World models need action-labeled data.

• 1X's open release is 100+ hours of a single robot (EVE).
• Cosmos 3 is open (OpenMDW) but post-training needs paired video and action data.
• Opportunity: supplying action-conditioned interaction data and evaluation sets.

9. GitHub OWNER/REPO list with stars

Tags as in the header; "nf" means not fetched today.

• google-deepmind/mujoco: 15k [GI]
• google-deepmind/mujoco_warp: 1.3k [GI]
• google-deepmind/mujoco_menagerie: nf (429)
• google-deepmind/mujoco_playground: nf (429)
• google-deepmind/dm_control: 4.7k [GI]
• newton-physics/newton: 5.6k [GH]
• newton-physics/newton-governance: nf
• newton-physics/mujoco-usd-converter: 75 [GI]
• newton-physics/urdf-usd-converter: 72 [GI]
• newton-physics/newton-usd-schemas: 14 [GI]
• NVIDIA/warp: 6.9k [GI]
• NVIDIA-Omniverse/PhysX: 4.7k [GI]
• isaac-sim/IsaacSim: ~4.0k [GH]
• isaac-sim/IsaacLab: 8.2k [GH]
• isaac-sim/IsaacLab-Arena: 557 [GH]
• isaac-sim/IsaacGymEnvs: nf
• mujocolab/mjlab: 3.1k [GI]
• Genesis-Embodied-AI/genesis-world: nf (429)
• Genesis-Embodied-AI/quadrants: 219 [GI]
• Genesis-Embodied-AI/nyx-for-genesis: 138 [GI]
• Genesis-Embodied-AI/RoboGen: 1.2k [GH]
• zhouxian/genesis-speed-benchmark: nf
• haosulab/ManiSkill (now mani-skill/ManiSkill): 3.3k [GI]
• haosulab/SAPIEN: 793 [GH]
• RobotLocomotion/drake: 4.1k [GH]
• gazebosim/gz-sim: 1.4k [GH]
• gazebosim/gz-physics: nf
• cyberbotics/webots: 4.5k [GH]
• projectchrono/chrono: 3.1k [GH]
• bulletphysics/bullet3: 14k [GI]
• google/brax: 3.2k [GI]
• robocasa/robocasa: 1.5k [GH]
• ARISE-Initiative/robosuite: 2.6k [GI]
• StanfordVL/BEHAVIOR-1K: 1.7k [GH]
• facebookresearch/habitat-sim: 3.8k [GH]
• facebookresearch/habitat-lab: 3.1k [GI]
• RoboVerseOrg/RoboVerse: 1.9k [GH]
• Farama-Foundation/Gymnasium-Robotics: 1.9k [GI]
• Farama-Foundation/Gymnasium: 12k [GI]
• Farama-Foundation/Metaworld: 1.8k [GI]
• princeton-vl/infinigen: 7.1k [GH]
• allenai/Holodeck: 572 [GH]
• allenai/ai2thor: 1.8k [GI]
• liruiw/GenSim: 350 [GH]
• TATP-233/DISCOVERSE: 518 [GH]
• NVIDIA/Cosmos: 11.7k [GH]
• nvidia-cosmos/cosmos-predict2.5: nf
• nvidia-cosmos/cosmos-transfer2.5: nf
• 1x-technologies/1xgpt: 561 [GH]
• NVlabs/ProtoMotions: 2.4k [GH]
• amazon-far/holosoma: 1.6k [GH]
• leggedrobotics/legged_gym: nf
• leggedrobotics/rsl_rl: 2.8k [GI]
• unitreerobotics/unitree_rl_lab: nf
• HybridRobotics/whole_body_tracking: nf
• LeCAR-Lab/HumanoidVerse: nf
• RoboTwin-Platform/RoboTwin: 2.8k [GH]
• robfiras/loco-mujoco: 1.4k [GI]
• vikashplus/robohive: 632 [GI]
• dartsim/dart: 1.1k [GI]

Other caveats

• Some GitHits "last pushed" dates may be cached. mujoco_warp, for example, showed 2026-08-13 despite later releases, so I relied on release dates there.
• The Drake GitHub sidebar (v1.54.0) conflicts with PyPI (1.57.0, 2026-09-10). I used PyPI.
• I did not name any company as a user unless a source stated it.