Simple-WAM

Renping Zhou*, Zanlin Ni*, Zihao Fan, Guohao Fu, Zeyu Liu, Hao Shi, Jie Zhang, Chi Bene Chen, Yang Yue, Xueyang Fu, Gao Huang†
(* indicates equal contribution, † means Co-corresponding author)

This repository contains the official implementation of the paper "What Makes World Action Models Generalize? An Empirical Study of Test-Time Future Modeling".

Environment Setup

1. Create the Environment

conda create -n simple-wam python=3.10 -y
conda activate simple-wam

2. Install Dependencies

Core model and data dependencies are pinned in requirements.txt; benchmark-specific environments are not included.

pip install torch==2.7.1+cu128 torchvision==0.22.1+cu128 \
  --index-url https://download.pytorch.org/whl/cu128
pip install -r requirements.txt
pip install -e .

Dataset Download

These trajectory datasets are needed for training, not for simulation evaluation with the released checkpoints.

LIBERO

Download the dataset from yuanty/LIBERO-fastwam into data/libero_mujoco3.3.2/, then extract each archive:

mkdir -p data/libero_mujoco3.3.2
# Place all four .tar.gz files in this directory first.
for archive in data/libero_mujoco3.3.2/*.tar.gz; do
  tar -xzf "$archive" -C data/libero_mujoco3.3.2
done

The existing data configs expect this layout:

data/libero_mujoco3.3.2/
  libero_10_no_noops_lerobot/
  libero_goal_no_noops_lerobot/
  libero_object_no_noops_lerobot/
  libero_spatial_no_noops_lerobot/

RoboTwin

Download all robotwin2.0.tar.gz.part-* files from yuanty/robotwin2.0-fastwam into data/robotwin2.0/. Concatenate the parts in filename order and extract:

mkdir -p data/robotwin2.0
# Place every archive part in this directory first.
cat data/robotwin2.0/robotwin2.0.tar.gz.part-* | tar -xzf - -C data/robotwin2.0

Expected layout:

data/robotwin2.0/
  robotwin2.0/
    data/
    meta/
    videos/

Evaluation

1. Download Checkpoints and Simulator Assets

Download the released checkpoints and simulator assets from rpzhou/Simple-WAM:

huggingface-cli download rpzhou/Simple-WAM \
  --repo-type model \
  --include "simplewam_checkpoints/*" "benchmark_assets/*" \
  --local-dir checkpoints

export PYTHONPATH="$(pwd)/src:${PYTHONPATH:-}"
export DIFFSYNTH_MODEL_BASE_PATH="$(pwd)/checkpoints"

If the files are already downloaded, skip the download command. Expected layout:

checkpoints/
  simplewam_checkpoints/
    libero_joint_2cam224_1e-4.pt
    libero_joint_2cam224_1e-4_fewshot10.pt
    ...
    robotwin_joint_3cam_384_1e-4_fewshot10.pt
    robotwin_joint_3cam_384_1e-4_taskgen.pt
    robotwin_joint_3cam_384_1e-4_taskgen_video.pt
    libero_dataset_stats.json
    robotwin_dataset_stats.json
  benchmark_assets/
    libero_standard.tar.gz
    libero_plus.tar.gz
    robotwin_assets.tar.gz

Wan VAE, text encoder, and tokenizer files are downloaded automatically on first use if missing. For offline evaluation, prepare those files in the same checkpoints/ model-cache directory beforehand. The trained VideoDiT and ActionDiT weights come from the released .pt file.

2. LIBERO

Install the simulator dependencies into the existing environment.

pip install -c requirements.txt \
  mujoco==3.3.2 robosuite==1.4.0 bddl==1.0.1 gym==0.25.2 \
  easydict==1.9 cloudpickle==2.1.0 future==0.18.2 \
  opencv-python==4.6.0.66 matplotlib==3.5.3 \
  h5py==3.16.0 scipy==1.13.1 PyOpenGL==3.1.10

tar -xzf checkpoints/benchmark_assets/libero_standard.tar.gz -C third_party/LIBERO
pip install -e third_party/LIBERO

export PYTHONPATH="$(pwd)/third_party/LIBERO:${PYTHONPATH:-}"
export LIBERO_CONFIG_PATH="$(pwd)/third_party/LIBERO/.libero"
export MUJOCO_GL=egl
export PYOPENGL_PLATFORM=egl

The archive restores the omitted third_party/LIBERO/libero/ directory, including assets, BDDL files, and initial states. Its paths are resolved through the bundled third_party/LIBERO/.libero/config.yaml.

Evaluate the full-data checkpoint on all four suites, with 50 trials per task:

config_name=libero_joint_2cam224_1e-4
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
python experiments/libero/run_libero_manager.py \
  "task=${config_name}" \
  "ckpt=checkpoints/simplewam_checkpoints/${config_name}.pt" \
  EVALUATION.dataset_stats_path=checkpoints/simplewam_checkpoints/libero_dataset_stats.json \
  'MULTIRUN.task_suite_names=[libero_spatial,libero_object,libero_goal,libero_10]' \
  MULTIRUN.num_gpus=8 \
  MULTIRUN.max_tasks_per_gpu=1 \
  MULTIRUN.persistent_workers=true \
  EVALUATION.num_trials=50 \
  EVALUATION.num_inference_steps=10 \
  EVALUATION.freeze_future_video_noise=true \
  EVALUATION.torch_compile_action=true \
  EVALUATION.offload_text_encoder=true

Use the same command with a different config_name to evaluate another released checkpoint. For task generalization, replace MULTIRUN.task_suite_names with the held-out suite:

Checkpoint/config suffix	Evaluation suites
`_fewshot5`, `_fewshot10`	All four suites
`_taskgen_spatial`, `_taskgen_video_spatial`	`[libero_spatial]`
`_taskgen_object`, `_taskgen_video_object`	`[libero_object]`
`_taskgen_goal`, `_taskgen_video_goal`	`[libero_goal]`
`_taskgen_long`, `_taskgen_video_long`	`[libero_10]`

All suffixes above follow libero_joint_2cam224_1e-4. Results are saved under evaluate_results/libero/<config_name>/.

3. LIBERO-plus

Install the simulator dependencies listed in LIBERO above, then add the image-corruption dependencies and extract the LIBERO-plus archive:

conda install -c conda-forge imagemagick -y
pip install -c requirements.txt Wand==0.7.2 scikit-image==0.25.2

tar -xzf checkpoints/benchmark_assets/libero_plus.tar.gz -C third_party/LIBERO-plus
pip install -e third_party/LIBERO-plus

export PYTHONPATH="$(pwd)/third_party/LIBERO-plus:$(pwd)/src:${PYTHONPATH:-}"
export LIBERO_CONFIG_PATH="$(pwd)/third_party/LIBERO-plus/.libero"
export NUMBA_CACHE_DIR="$(pwd)/.numba_cache"
export MPLCONFIGDIR="$(pwd)/.matplotlib_cache"
export MUJOCO_GL=egl
export PYOPENGL_PLATFORM=egl

python -c "import libero.libero; print(libero.libero.__file__)"

The printed path must be under third_party/LIBERO-plus. Both benchmarks use the same Python package name, libero; installing LIBERO-plus replaces the editable LIBERO installation. The explicit PYTHONPATH and LIBERO_CONFIG_PATH above select the plus benchmark in this shell. To switch back to standard LIBERO, rerun its editable install and environment exports from the previous section.

Use the same released LIBERO checkpoint and normalization statistics. This command evaluates all four robustness suites with one rollout per task variant:

config_name=libero_joint_2cam224_1e-4
run_id=$(date +%Y%m%d_%H%M%S)
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
python experiments/libero/run_libero_manager.py \
  "task=${config_name}" \
  "ckpt=checkpoints/simplewam_checkpoints/${config_name}.pt" \
  EVALUATION.dataset_stats_path=checkpoints/simplewam_checkpoints/libero_dataset_stats.json \
  "EVALUATION.output_dir=./evaluate_results/libero_plus/${config_name}/${run_id}" \
  'MULTIRUN.task_suite_names=[libero_spatial,libero_object,libero_goal,libero_10]' \
  MULTIRUN.num_gpus=8 \
  MULTIRUN.max_tasks_per_gpu=1 \
  MULTIRUN.persistent_workers=true \
  EVALUATION.num_trials=1 \
  EVALUATION.num_inference_steps=10 \
  EVALUATION.freeze_future_video_noise=true \
  EVALUATION.torch_compile_action=true \
  EVALUATION.offload_text_encoder=true

After evaluation, summarize Camera, Robot, Language, and the other components:

python experiments/libero/summarize_libero_plus_components.py \
  --run-dir "evaluate_results/libero_plus/${config_name}/${run_id}"

The summary CSV and JSON files are written into that run directory.

4. RoboTwin

Our reference RoboTwin environment uses CUDA Toolkit 12.8.1 and PyTorch 2.7.1+cu128. The key simulator packages are SAPIEN 3.0.0b1, mplib 0.2.1, cuRobo 0.7.5, Warp 1.14.0, Open3D 0.19.0, and toppra 0.6.8. RoboTwin rendering also requires a working Vulkan setup and ffmpeg.

Machine and driver setups vary. Follow the official RoboTwin repository for installation instructions and environment-specific troubleshooting, while using the versions above as the reference configuration for reproducing our evaluation.

After configuring RoboTwin, extract the released assets and expose the Simple-WAM policy and checkpoints:

tar -xzf checkpoints/benchmark_assets/robotwin_assets.tar.gz -C third_party/RoboTwin

ln -sfn ../../../experiments/robotwin/simplewam_policy \
  third_party/RoboTwin/policy/simplewam_policy
ln -sfn ../../checkpoints third_party/RoboTwin/checkpoints

Evaluate the few-shot checkpoint on all tasks, in both clean and randomized phases:

config_name=robotwin_joint_3cam_384_1e-4_fewshot10
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
python experiments/robotwin/run_robotwin_manager.py \
  "task=${config_name}" \
  "ckpt=checkpoints/simplewam_checkpoints/${config_name}.pt" \
  EVALUATION.dataset_stats_path=checkpoints/simplewam_checkpoints/robotwin_dataset_stats.json \
  EVALUATION.eval_phase=both \
  EVALUATION.eval_num_episodes=100 \
  EVALUATION.num_inference_steps=10 \
  EVALUATION.freeze_future_video_noise=true \
  EVALUATION.torch_compile_action=true \
  EVALUATION.offload_text_encoder=true \
  MULTIRUN.num_gpus=8 \
  MULTIRUN.max_tasks_per_gpu=1

For the generalization checkpoints, change config_name and append the matching override to evaluate only the held-out tasks:

`config_name`	Additional override
`robotwin_joint_3cam_384_1e-4_taskgen`	`'EVALUATION.task_names=${data.train.robotwin_drop_tasks}'`
`robotwin_joint_3cam_384_1e-4_taskgen_video`	`'EVALUATION.task_names=${data.train.robotwin_action_loss_drop_tasks}'`

Training

1. Preprocessing

Run the following commands from the repository root after installing Simple-WAM and extracting the datasets. Use the full-data configs below, not a few-shot or task-generalization config, so the caches cover all training subsets. For RoboTwin, place the normalization statistics at data/robotwin2.0/dataset_stats.json before computing video or metadata caches.

Prepare the ActionDiT Initialization

The preprocessing scripts download missing Wan weights and tokenizer files on first use. Set their local cache directory:

mkdir -p checkpoints
export DIFFSYNTH_MODEL_BASE_PATH="$(pwd)/checkpoints"

Interpolate the pretrained Wan2.2 video backbone to the 1024-dimensional ActionDiT backbone, with alpha scaling enabled:

python scripts/preprocess_action_dit_backbone.py \
  --model-config configs/model/simplewam.yaml \
  --output checkpoints/ActionDiT_linear_interp_Wan22_alphascale_1024hdim.pt \
  --device cuda \
  --dtype bfloat16

Precompute Text Cache

Encode the task instructions from each dataset's meta/tasks.jsonl:

# LIBERO
CUDA_VISIBLE_DEVICES=0 python scripts/precompute_text_embeds.py \
  task=libero_joint_2cam224_1e-4 \
  +overwrite=false

# RoboTwin
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
torchrun --standalone --nproc_per_node=8 scripts/precompute_text_embeds.py \
  task=robotwin_joint_3cam_384_1e-4 \
  +overwrite=false

Outputs are written to data/text_embeds_cache/libero/ and data/text_embeds_cache/robotwin/, as configured by data.train.text_embedding_cache_dir. Existing entries are skipped; use +overwrite=true to regenerate them. The script loads the text encoder even though training uses model.load_text_encoder=false.

Precompute Video Latents

Precomputed video latents matching the released configs are available from rpzhou/simplewam-precompute-cache. Download and install them from the repository root:

huggingface-cli download rpzhou/simplewam-precompute-cache \
  --repo-type dataset \
  --include "video_latents/libero.tar.gz" "video_latents/robotwin/*" \
  --local-dir ./cache_downloads

mkdir -p ./data/video_latents/libero ./data/video_latents/robotwin
tar -xzf ./cache_downloads/video_latents/libero.tar.gz \
  -C ./data/video_latents/libero --strip-components=1

set -o pipefail
cat ./cache_downloads/video_latents/robotwin/robotwin_part_{aa,ab,ac,ad,ae,af} | \
  tar -xzf - -C ./data/video_latents/robotwin --strip-components=1

Alternatively, compute the caches locally. The commands below use eight GPUs, with one process per GPU. Adjust CUDA_VISIBLE_DEVICES and --nproc_per_node together for your machine.

# LIBERO
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
torchrun --standalone --nproc_per_node=8 scripts/precompute_video_latents.py \
  task=libero_joint_2cam224_1e-4 \
  data.train.use_precomputed_metadata_cache=false \
  data.train.metadata_cache_dir=null \
  data.train.video_latent_cache_dir=./data/video_latents/libero \
  data.train.video_latent_storage_format=npz_compressed \
  overwrite_video_latents=false \
  video_latent_save_dtype=fp16 \
  video_latent_batch_size=8 \
  video_latent_num_workers=8

# RoboTwin
CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
torchrun --standalone --nproc_per_node=8 scripts/precompute_video_latents.py \
  task=robotwin_joint_3cam_384_1e-4 \
  data.train.robotwin_clean_only=false \
  data.train.use_precomputed_metadata_cache=false \
  data.train.metadata_cache_dir=null \
  data.train.video_latent_cache_dir=./data/video_latents/robotwin \
  data.train.video_latent_storage_format=npz_compressed \
  overwrite_video_latents=false \
  video_latent_save_dtype=fp16 \
  video_latent_batch_size=8 \
  video_latent_num_workers=8

The output paths match the current training configs. ./data/video_latents/libero and ./data/video_latents/robotwin are relative to the current working directory. Run these commands from the repository root to store caches under its data/. If you change the VAE, frame sampling, resolution, or camera layout, generate a new cache and update data.train.video_latent_cache_dir accordingly.

Precompute RoboTwin Metadata Cache

Ensure data/robotwin2.0/dataset_stats.json is present first. This CPU-only step caches normalized actions, proprioception, padding masks, and instructions; it does not run the VAE or text encoder.

A compatible precomputed cache is also available from rpzhou/simplewam-precompute-cache:

huggingface-cli download rpzhou/simplewam-precompute-cache \
  --repo-type dataset \
  --include "metadata_cache/robotwin/*" \
  --local-dir ./cache_downloads

mkdir -p ./data/metadata_cache/robotwin
cp -a ./cache_downloads/metadata_cache/robotwin/. \
  ./data/metadata_cache/robotwin/

To recompute it locally, note that the metadata script expects a resolved configuration, not a task YAML with Hydra defaults. Export one without starting preprocessing:

mkdir -p ./data/metadata_cache
python scripts/precompute_video_latents.py \
  task=robotwin_joint_3cam_384_1e-4 \
  data.train.robotwin_clean_only=false \
  data.train.use_precomputed_video_latents=false \
  data.train.use_precomputed_metadata_cache=false \
  data.train.metadata_cache_dir=null \
  --cfg job --resolve > ./data/metadata_cache/robotwin_precompute.yaml

python scripts/precompute_metadata_cache.py \
  --config ./data/metadata_cache/robotwin_precompute.yaml \
  --output-cache-dir ./data/metadata_cache/robotwin \
  --shard-size 10000 \
  --batch-size 64 \
  --num-workers 8

The relative output path ./data/metadata_cache/robotwin matches data.train.metadata_cache_dir in the RoboTwin training config. Run from the repository root. Existing arrays are skipped unless --overwrite is passed. Regenerate the cache if normalization statistics, action processing, or sample indexing changes.

2. Training Commands

Run from the repository root after preparing the datasets, ActionDiT initialization, text cache, and video latents above. RoboTwin also uses the metadata cache. Training uses DeepSpeed ZeRO-1 and BF16 through scripts/train_zero1.sh; no simulator environment is needed for training.

LIBERO

Train on all four suites with eight GPUs:

CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
bash scripts/train_zero1.sh 8 \
  task=libero_joint_2cam224_1e-4 \
  gradient_accumulation_steps=2 \
  wandb.mode=offline

Replace task= with the corresponding config below; keep the other arguments unchanged:

Task config	Training setting
`libero_joint_2cam224_1e-4`	Full data, all four suites
`libero_joint_2cam224_1e-4_fewshot5`	5 demonstrations per task
`libero_joint_2cam224_1e-4_fewshot10`	10 demonstrations per task
`libero_joint_2cam224_1e-4_taskgen_spatial`	Exclude the spatial suite
`libero_joint_2cam224_1e-4_taskgen_object`	Exclude the object suite
`libero_joint_2cam224_1e-4_taskgen_goal`	Exclude the goal suite
`libero_joint_2cam224_1e-4_taskgen_long`	Exclude the long-horizon suite (`libero_10`)
`libero_joint_2cam224_1e-4_taskgen_video_spatial`	Spatial suite contributes video supervision only
`libero_joint_2cam224_1e-4_taskgen_video_object`	Object suite contributes video supervision only
`libero_joint_2cam224_1e-4_taskgen_video_goal`	Goal suite contributes video supervision only
`libero_joint_2cam224_1e-4_taskgen_video_long`	Long-horizon suite contributes video supervision only

LIBERO-plus evaluates the same trained LIBERO models; it does not require a separate training command.

RoboTwin

Train the few-shot setting with eight GPUs:

CUDA_VISIBLE_DEVICES=0,1,2,3,4,5,6,7 \
bash scripts/train_zero1.sh 8 \
  task=robotwin_joint_3cam_384_1e-4_fewshot10 \
  gradient_accumulation_steps=16 \
  wandb.mode=offline

Replace task= to select another training setting:

Task config	Training setting
`robotwin_joint_3cam_384_1e-4`	Full clean and randomized data
`robotwin_joint_3cam_384_1e-4_fewshot10`	10 episodes per task sampled from the combined clean and randomized data
`robotwin_joint_3cam_384_1e-4_taskgen`	Exclude tasks listed in `data.train.robotwin_drop_tasks`
`robotwin_joint_3cam_384_1e-4_taskgen_video`	Tasks in `data.train.robotwin_action_loss_drop_tasks` contribute video supervision only

Batch Size and Outputs

The examples use global batch sizes of 128 (LIBERO) and 1024 (RoboTwin), giving a per-GPU microbatch of 8 in both commands:

per_gpu_batch_size = global_batch_size / (num_gpus * gradient_accumulation_steps)

When changing GPU count, update both CUDA_VISIBLE_DEVICES and the positional argument to train_zero1.sh. Increase gradient_accumulation_steps to reduce per-GPU memory while keeping global_batch_size fixed; the division above must remain exact. Epoch counts, checkpoint intervals, and any step limits come from the selected task config.

Each launch writes its resolved config.yaml, checkpoints/weights/step_XXXXXX.pt, and checkpoints/state/ under runs/<task>/<timestamp>/. wandb.mode=offline keeps W&B logging local; use wandb.enabled=false to disable it entirely.

Acknowledgements

We thank the authors and maintainers of the following open-source projects:

FastWAM for the codebase on which Simple-WAM is built and the preprocessed datasets used in this repository.
LIBERO for the benchmark and simulation environment.
LIBERO-plus for the robustness benchmark.
RoboTwin for the simulation environment, tasks, and assets.

BibTeX

@misc{zhou2026makesworldactionmodels,
      title={What Makes World Action Models Generalize? An Empirical Study of Test-Time Future Modeling}, 
      author={Renping Zhou and Zanlin Ni and Zihao Fan and Guohao Fu and Zeyu Liu and Hao Shi and Jie Zhang and Chi Bene Chen and Yang Yue and Xueyang Fu and Gao Huang},
      year={2026},
      eprint={2609.34981},
      archivePrefix={arXiv},
      primaryClass={cs.CV},
      url={https://arxiv.org/abs/2609.34981}, 
}

Name		Name	Last commit message	Last commit date
assets		assets
configs		configs
experiments		experiments
scripts		scripts
src/simplewam		src/simplewam
third_party		third_party
LICENSE		LICENSE
README.md		README.md
__init__.py		__init__.py
pyproject.toml		pyproject.toml
requirements.txt		requirements.txt

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Repository files navigation

Simple-WAM

Environment Setup

1. Create the Environment

2. Install Dependencies

Dataset Download

LIBERO

RoboTwin

Evaluation

1. Download Checkpoints and Simulator Assets

2. LIBERO

3. LIBERO-plus

4. RoboTwin

Training

1. Preprocessing

Prepare the ActionDiT Initialization

Precompute Text Cache

Precompute Video Latents

Precompute RoboTwin Metadata Cache

2. Training Commands

LIBERO

RoboTwin

Batch Size and Outputs

Acknowledgements

BibTeX

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Simple-WAM

Environment Setup

1. Create the Environment

2. Install Dependencies

Dataset Download

LIBERO

RoboTwin

Evaluation

1. Download Checkpoints and Simulator Assets

2. LIBERO

3. LIBERO-plus

4. RoboTwin

Training

1. Preprocessing

Prepare the ActionDiT Initialization

Precompute Text Cache

Precompute Video Latents

Precompute RoboTwin Metadata Cache

2. Training Commands

LIBERO

RoboTwin

Batch Size and Outputs

Acknowledgements

BibTeX

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