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DreamZero

Source https://github.com/vllm-project/vllm-omni/tree/main/examples/online_serving/dreamzero.

DreamZero is the robot-policy serving example for the OpenPI-compatible /v1/realtime/robot/openpi endpoint.

Supported checkpoints

Model HuggingFace repo
DreamZero-DROID GEAR-Dreams/DreamZero-DROID

Quick start

Start the server

bash examples/online_serving/dreamzero/run_server.sh

By default this launches:

vllm serve GEAR-Dreams/DreamZero-DROID --omni --port 8000 \
    --served-model-name dreamzero-droid \
    --deploy-config vllm_omni/deploy/dreamzero_tp1_cfg2.yaml \
    --enforce-eager --disable-log-stats

Override MODEL, PORT, HOST, DEPLOY_CONFIG, or SERVED_MODEL_NAME through the script environment if needed.

Install example dependencies

The core pip install -e . setup does not include the extra packages used by the DreamZero example scripts.

  • openpi_client.py: openpi-client, websockets, opencv-python
  • droid_sim_eval_client.py: mediapy, websockets, openpi-client

The DROID sim-eval script also needs an Isaac Lab environment that provides isaaclab, isaaclab_tasks, sim_evals, and gymnasium.

If you run the DROID client on Python < 3.12, also install typing-extensions.

Configure TP and CFG parallelism

The bundled DreamZero configs intentionally keep only:

Config Purpose
vllm_omni/deploy/dreamzero.yaml Default TP=1, CFG parallel disabled
vllm_omni/deploy/dreamzero_tp1_cfg2.yaml TP=1, CFG parallel size=2

For other topologies, use CLI parallelism flags and update stage 0 devices with --stage-overrides. The number of listed devices must match tensor_parallel_size * cfg_parallel_size.

TP=2 with CFG parallel disabled:

vllm serve GEAR-Dreams/DreamZero-DROID --omni --port 8000 \
    --served-model-name dreamzero-droid \
    --deploy-config vllm_omni/deploy/dreamzero.yaml \
    --tensor-parallel-size 2 \
    --stage-overrides '{"0": {"devices": "0,1"}}' \
    --enforce-eager --disable-log-stats

TP=2 with CFG parallel size=2:

vllm serve GEAR-Dreams/DreamZero-DROID --omni --port 8000 \
    --served-model-name dreamzero-droid \
    --deploy-config vllm_omni/deploy/dreamzero.yaml \
    --tensor-parallel-size 2 \
    --cfg-parallel-size 2 \
    --stage-overrides '{"0": {"devices": "0,1,2,3"}}' \
    --enforce-eager --disable-log-stats

Download example assets

The OpenPI client and DROID sim-eval example expect the three camera MP4 files in outputs/dreamzero/assets.

hf download YangshenDeng/vllm-omni-dreamzero-assets --repo-type dataset --local-dir outputs/dreamzero/assets

Run the OpenPI client

python examples/online_serving/dreamzero/openpi_client.py \
    --host 127.0.0.1 \
    --port 8000 \
    --video-dir outputs/dreamzero/assets

This client uses downloaded example videos and talks to the OpenPI websocket server.

Run DROID sim eval

${ISAACLAB_LAUNCHER} -p examples/online_serving/dreamzero/droid_sim_eval_client.py \
    --host 127.0.0.1 \
    --port 8000 \
    --scene 1 \
    --episodes 1 \
    --headless \
    --device cuda:0

Set ISAACLAB_LAUNCHER=path/to/isaaclab.sh from the vLLM-Omni repository root before running the command. This launches Isaac Lab / sim-evals and runs the DROID benchmark loop against the same websocket endpoint.

Export comparison videos offline

python examples/offline_inference/dreamzero/export_prediction_video.py \
    --deploy-config vllm_omni/deploy/dreamzero_tp1_cfg2.yaml \
    --save-input-video \
    --save-gif

The export script uses local Omni inference, not the websocket server. It writes the input rollout video and the predicted output video artifacts for side-by-side inspection.

MolmoSpace demo

python examples/online_serving/dreamzero/molmospace_dreamzero_eval_demo.py \
    --host 127.0.0.1 \
    --port 8000 \
    --benchmark_dir /path/to/benchmark \
    --output_dir /path/to/output

This demo adapts DreamZero to the MolmoSpace-style remote policy eval loop.

Example materials

droid_sim_eval_client.py

Large file omitted from the rendered docs. View it on GitHub: https://github.com/vllm-project/vllm-omni/blob/main/examples/online_serving/dreamzero/droid_sim_eval_client.py.

molmospace_dreamzero_eval_demo.py
from __future__ import annotations

import argparse
import os
import sys
from pathlib import Path

os.environ.setdefault("MUJOCO_GL", "egl")
os.environ.setdefault("PYOPENGL_PLATFORM", "egl")

# Import base configs at module top level so the subclasses below are pickle-
# resolvable (worker processes import this module fresh via __main__).
from molmo_spaces.configs.policy_configs_baselines import (  # noqa: E402
    DreamZeroPolicyConfig,
)
from molmo_spaces.evaluation.configs.evaluation_configs import (  # noqa: E402
    DreamZeroPolicyEvalConfig,
)


# We only need to change the backend host and port to the vllm-host!
class DreamZeroVllmOmniPolicyConfig(DreamZeroPolicyConfig):
    remote_config: dict = dict(host="127.0.0.1", port=8000)


class DreamZeroVllmOmniEvalConfig(DreamZeroPolicyEvalConfig):
    policy_config: DreamZeroVllmOmniPolicyConfig = DreamZeroVllmOmniPolicyConfig()


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--host", default="127.0.0.1")
    parser.add_argument("--port", type=int, default=8000)
    parser.add_argument(
        "--benchmark_dir",
        required=True,
        help=(
            "Path to a MolmoSpaces benchmark directory, for example "
            "$MOLMOSPACES_BENCHMARK_DIR/20260327/ithor/FrankaCloseHardBench/"
            "FrankaCloseHardBench_20260206_json_benchmark"
        ),
    )
    parser.add_argument("--max_episodes", type=int, default=1)
    parser.add_argument("--task_horizon_steps", type=int, default=80)
    parser.add_argument(
        "--output_dir",
        required=True,
        help="Directory to write evaluation outputs (created if missing).",
    )
    parser.add_argument("--episode_idx", type=int, default=None)
    args = parser.parse_args()

    policy_config = DreamZeroVllmOmniPolicyConfig(remote_config=dict(host=args.host, port=args.port))
    DreamZeroVllmOmniPolicyConfig.model_fields["remote_config"].default = policy_config.remote_config
    DreamZeroVllmOmniEvalConfig.model_fields["policy_config"].default = policy_config

    # Import after env vars are set so MuJoCo picks EGL.
    from molmo_spaces.evaluation import run_evaluation

    cfg_cls = DreamZeroVllmOmniEvalConfig

    output_dir = args.output_dir
    Path(output_dir).mkdir(parents=True, exist_ok=True)

    print(f"[eval] benchmark_dir={args.benchmark_dir}")
    print(f"[eval] max_episodes={args.max_episodes} task_horizon_steps={args.task_horizon_steps}")
    print(f"[eval] remote policy: ws://{args.host}:{args.port}/v1/realtime/robot/openpi")

    results = run_evaluation(
        eval_config_cls=cfg_cls,
        benchmark_dir=Path(args.benchmark_dir),
        max_episodes=args.max_episodes,
        task_horizon_steps=args.task_horizon_steps,
        num_workers=1,
        use_wandb=False,
        output_dir=output_dir,
        episode_idx=args.episode_idx,
    )

    print(f"[eval] success={results.success_count}/{results.total_count} ({results.success_rate:.1%})")
    print(f"[eval] output_dir={results.output_dir}")
    return 0


if __name__ == "__main__":
    sys.exit(main())
openpi_client.py

Large file omitted from the rendered docs. View it on GitHub: https://github.com/vllm-project/vllm-omni/blob/main/examples/online_serving/dreamzero/openpi_client.py.

run_server.sh
#!/usr/bin/env bash
set -euo pipefail

MODEL="${MODEL:-GEAR-Dreams/DreamZero-DROID}"
HOST="${HOST:-127.0.0.1}"
PORT="${PORT:-8000}"
DEPLOY_CONFIG="${DEPLOY_CONFIG:-vllm_omni/deploy/dreamzero_tp1_cfg2.yaml}"
SERVED_MODEL_NAME="${SERVED_MODEL_NAME:-dreamzero-droid}"

args=(
  serve
  "$MODEL"
  --omni
  --host "$HOST"
  --port "$PORT"
  --served-model-name "$SERVED_MODEL_NAME"
  --deploy-config "$DEPLOY_CONFIG"
  --enforce-eager
  --disable-log-stats
)

ATTENTION_BACKEND="${ATTENTION_BACKEND:-torch}" \
DIFFUSION_ATTENTION_BACKEND="${DIFFUSION_ATTENTION_BACKEND:-TORCH_SDPA}" \
vllm "${args[@]}"