FAQ#

Installation#

No module named 'cv2' (or scipy, mink)#

The environment was synced without the extra that provides the module. Name every extra in one uv sync, as in Installation.

Rendering#

Rendering fails on a headless Linux machine#

MuJoCo defaults to a windowed OpenGL context, which needs a display. Render through EGL instead:

export MUJOCO_GL=egl

Rendering fails on macOS with MUJOCO_GL=egl#

macOS has no EGL. Leave MUJOCO_GL unset and drop it from the commands in these pages.

Environment and demonstrations#

Can I set reset_warmup_steps to 0 to save time?#

No. The demonstrations start after the 200-step warmup, so a run without it does not match them and is not official.

Which episode length should I use?#

Use the length make(task) sets (TASKS[task].episode_length). The episode_length in a batch’s metadata.json is the collector’s cap (Episode budgets).

get_demos() raises DemosUnavailableError#

The task has no published demonstrations yet. bigym-download --list shows which tasks do.

get_demos() says the demonstrations do not match this env#

The loader compares the dataset’s robot, backend, downsample rate, cameras and observation and action dimensions with the env. A camera override such as camera_keys=("head",) is the usual cause. Build the env with make(task) or make_gym(task), or re-render the dataset for another camera setup with bigym-rerender-lerobot.

How do I work offline?#

Download once, then tell the Hub client to stay on its cache:

uv run bigym-download --all
export HF_HUB_OFFLINE=1

Evaluation#

My result has no leaderboard record#

The runner writes a record only for an official run with 100 episodes. result["protocol_violations"] lists every result-affecting override. Official overrides lists the ones that keep a run official.

Are my numbers comparable with someone else’s?#

Official results are comparable when their substrate_version matches. See Determinism and versioning.

VR collection#

Can I collect demonstrations on macOS?#

No. The collector needs an OpenXR runtime, and macOS has none. Use Linux with WiVRn and a Quest 3, as in Collecting demonstrations.

Coding-agent benchmark#

bigym-agent run refuses my model#

Each harness runs only its own vendor’s models (codex for OpenAI, claude for Anthropic). Switch the harness to match the model.

My Claude Code subscription session stops authenticating mid-run#

A copied host .credentials.json shares one short-lived token between host and container, and one refresh revokes the other. Create a dedicated token for container sessions:

claude setup-token        # then set CLAUDE_CODE_OAUTH_TOKEN