SuperMimic reproduction on Isaac Lab 3 (kit-less, MuJoCo-Warp)

Unofficial reproduction of SuperMimic: Scaling Humanoid Whole-Body Control with One Differentiable World Model (arXiv 2610.28480) — no official code is released, so everything here is implemented from the paper. Target experiment: the controlled LAFAN1 comparison (Fig. 4a): 40 G1-retargeted LAFAN1 clips (2.45 h), one GPU; the paper reaches evaluation normalized return 0.82 after 1.2 h on an H100.

Author: Chong Zhang (ETH Zurich). License: MIT.

Disclaimer: this repository was speed-vibecoded in 1 hour with an AI coding assistant. It deliberately does not live under any lab's organization, because the code is too much "slop" for that: fast and unreviewed. Use it at your own risk.

One G1 motion tracker for all 40 LAFAN1 clips, trained in only ~1.5 GPU-hours (1.47 h on a single RTX PRO 6000): evaluation return 0.829 with 0/40 failed clips. For scale, the paper's PPO-in-simulator baseline does not reach return 0.82 within 18 h on up to 8 GPUs.

Solid robot: the trained policy simulated in Isaac Lab with MuJoCo-Warp. Blue ghost: the reference motion. Clips: dance, jumps, fall-and-get-up, sprint.

Progress and timestamps: MILESTONES.md.

Neither Isaac Lab nor any data is included in this repository; the steps below fetch them.

Requirements: Linux, an NVIDIA GPU (tested: RTX PRO 6000 Blackwell, driver 580 / CUDA 13), Docker with the NVIDIA Container Toolkit (docker run --gpus must work), ~20 GB of disk for the images and ~0.2 GB for the data.

Physics: Newton with the MuJoCo-Warp solver (NewtonCfg(MJWarpSolverCfg(...))), no Kit, no PhysX; 50 Hz control, 4 substeps of 5 ms, implicitfast integrator, MuJoCo collision pipeline.

The code runs against Isaac Lab 3 main at commit 46d6cc3 (VERSION 3.0.0), unmodified, inside Isaac Lab's kit-less image (no Isaac Sim / Kit, no PhysX). Newer main commits may work but are untested.

tools/setup.sh

which is equivalent to:

git clone https://github.com/isaac-sim/IsaacLab.git
git -C IsaacLab checkout 46d6cc3d7b115906fad12efd372fbf69f4e3d3ed
(cd IsaacLab && docker build -f docker/Dockerfile.kitless -t isaac-lab-kitless:main-46d6cc3 .)
docker build -t supermimic:latest docker/     # + tmux, ffmpeg, gcc, NVIDIA EGL vendor file

Then start the long-lived container (repository mounted at /workspace/supermimic):

docker/run_container.sh 0 128g     # GPU index 0, 128 GB memory cap

With the container from step 1 running:

tools/download_data.sh

It downloads both, then converts the robot inside the container: tools/urdf_to_mjcf.py compiles the URDF into data/g1_description/g1_29dof.xml (free-floating pelvis), and tools/mjcf_to_usd.py converts that MJCF to data/g1_usd/g1_29dof/g1_29dof.usda, which Isaac Lab spawns. The conversion is offline because the kit-less importers cannot run inside an Isaac Lab process (see Deviations). Expected result:

data/
├── lafan1_g1/                  40 CSVs (dance, fallAndGetUp, fight, jumps, run, sprint, walk)
├── g1_description/
│   ├── g1_29dof_rev_1_0.urdf
│   ├── g1_29dof.xml            generated MJCF
│   └── meshes/*.STL            38 meshes
└── g1_usd/g1_29dof/            generated USD (+ payloads/)

Check: ls data/lafan1_g1 | wc -l prints 40, and the clips total 264,705 frames at 30 fps (2.45 h). tools/test_env.py checks the converted robot against the reference motions (FK vs. simulator should agree to ~1e-6):

docker exec supermimic python tools/test_env.py

CPUS=0-23 ./run_train.sh lafan1_main          # training in tmux session 'lafan1_main' (optional CPU pinning)
docker exec -it supermimic tmux attach -t lafan1_main
docker exec supermimic tmux new -d -s eval_main "cd /workspace/supermimic && python supermimic/evaluate.py --run_dir logs/lafan1_main --watch"
docker exec supermimic python tools/plot.py logs/lafan1_main --out results/success_curve.png
docker exec supermimic python supermimic/evaluate.py --run_dir logs/lafan1_main --ckpt logs/lafan1_main/ckpt_014000.pt --record traj.npz
docker exec supermimic python tools/render.py traj.npz out.mp4 --clips dance2_subject1 --seconds 10

The first iterations are slow while torch.compile builds its kernels (cached in .cache/). Checkpoints are written every 2000 iterations to logs/<run>/; the eval watcher scores each on all 40 clips and appends to logs/<run>/eval.csv.

Evaluation return 0.824 at 1.24 h of training (paper: 0.82 at 1.2 h on an H100) and 0.829 with 0/40 failed clips at 1.47 h (iteration 14000).

• G1 29-DoF, BeyondMimic actuators (10 Hz natural frequency, damping ratio 2, motor armatures, action scale 0.25·τmax/Kp) — supermimic/robot.py.
• Reference library: 30 -> 50 Hz resampling, finite-difference velocities, FK of 14 tracked bodies, 1 s bins — supermimic/motion.py, differentiable torch FK supermimic/kinematics.py (matches the simulator's link poses/velocities to 1e-6).
• MDP (App. A): observation (q−q0, q̇, IMU ω, projected gravity, a_{t−1}; 10-frame history; Table A.1 noise), K=10 future reference frames as the goal, BeyondMimic tracking reward without the self-collision term and joint-limit weight −2, termination |e_z|>0.25 m or e_tilt>0.8, sim context ξ = (friction U[0.3,1.2], joint offsets U[±0.01], torso CoM offset) — supermimic/mdp.py.
• Simulator wrapper with return-based reset sampling (50% uniform / 40% softmax(−25 G_b/G_max) / 10% past-softmax) — supermimic/env.py.
• World model f_ω: MLP(2048,2048,2048) on heading-invariant state features + action + ξ, predicting frame-local increments; fit on k=8-step autoregressive windows (Eq. 1); analytic reward, observation and termination heads — supermimic/networks.py, supermimic/train.py.
• Policy: motion encoder MLP(2048,1024,512,256)->z∈R^32 (tanh), shared decoder MLP(2048,1024,512,256); critic MLP(256,128). BPTT over H=32 imagined steps from replay-buffer states with a soft survival weight and critic bootstrap (Eq. 2); critic on GAE(λ=0.95) targets (Eq. 3), 5 epochs × 4 minibatches.
• Hyperparameters as Table A.5: 4096 envs, buffer 1000 steps/env, action noise N(0, 0.1²), UTD 0.4 (2.5 vectorized sim steps per iteration), 10 WM batches of 2048 windows per iteration, 4096 imagined rollouts, Adam lr 2e-4 (policy β=(0.9,0.95)), cosine decay to 0.03× over 250k iterations, grad clip 1.0 (+ element-wise 0.1 for the policy), γ=0.99.
• Evaluation (App. F.1): each clip once from its first frame, friction 1.0, no DR/noise, deterministic policy; failure = training termination — supermimic/evaluate.py.

• Self-collisions disabled in the simulator (speed); robot–ground contacts use the URDF's convex mesh hulls and foot spheres.
• bf16 autocast for MLP matmuls (paper: TF32). On this RTX PRO 6000 it is 24 % faster; all state integration, FK and rewards stay fp32.
• Reward, observation and termination heads are analytic (allowed by §3.2); termination in imagination is a sigmoid-softened version of the hard thresholds.
• The policy observation additionally contains the reference root orientation relative to the robot root (6D), i.e. BeyondMimic's motion_anchor_ori_b — IMU-observable; no global position.
• 500 world-model-only warm-up iterations before policy updates start.
• Torso-CoM and friction are randomized once per environment at start-up (BeyondMimic's start-up events); joint offsets are resampled every episode. Episodes time out after 10 s or at the clip end (bootstrapped, not terminal).
• Do not run under a virtual-memory ulimit -v: Isaac Lab + Warp reserve ~430 GB of virtual address space (CUDA VA reservations; RSS ~3 GB) and Warp's CUDA-graph capture needs its mempool, which cannot initialize under such a limit. Cap memory with the container's cgroup (--memory) instead. Rootless docker ignores --cpuset-cpus; pin CPUs with taskset (CPUS=... in run_train.sh).
• Asset import: the kit-less URDF/MJCF importers fail inside a running Isaac Lab process (PhysxJointAPI schema not registered), so the USD is converted once, offline, by tools/mjcf_to_usd.py (registers the importer's schema plugin first) and spawned with UsdFileCfg(variants={"Physics": "mujoco"}).

• Method: Q. Liao, Y. Shao, J. Long, K. Zakka, R. Horowitz, P. Abbeel, K. Sreenath, SuperMimic: Scaling Humanoid Whole-Body Control with One Differentiable World Model, CoRL 2026, arXiv:2610.28480. This code is an independent re-implementation, not affiliated with the authors.
• Isaac Lab (BSD-3-Clause), Newton and MuJoCo-Warp (Apache-2.0) are used unmodified.
• LAFAN1 motions (Ubisoft La Forge): CC BY-NC-ND 4.0; G1 retargets and description by Unitree (BSD-3-Clause). The motion data is not redistributed here; the demo GIF shows the reference motions for illustration only and is not covered by this repository's MIT license.

The code in this repository is released under the MIT License.

Copyright (c) 2026 ETH Zurich, Chong Zhang.