docs/caveats.md

Known caveats and roadmap

For known sensor-level anomalies and the bad_frames.json skip-list, see quality.md.

What this dataset is and isn't

React is a dense multimodal interaction stream intended for learning dynamics / world models over short multimodal windows. It is not:

• A demonstration / policy-learning dataset. "Episodes" here are just file boundaries — they don't carry semantic / action structure.
• Comparable apples-to-apples with BridgeData V2, DROID, RT-1, ALOHA, etc. on "number of demos." The relevant comparison is hours of synchronized multimodal contact-rich interaction.

OT-uninitialized prefixes (already trimmed from .pt)

Three episodes on 2026-05-11 had OptiTrack offline at the moment the operator pressed s to start recording. RealSense + GelSight kept capturing fresh frames; OT held a stale (or zero) pose until the mocap software came online:

Episode	Trimmed prefix	What it was
episode_005	81 s (2,429 frames)	OT had 50 samples in the prefix (0.6 Hz)
episode_012	324 s (9,719 frames)	OT had 3 samples in the prefix
episode_017	641 s (19,228 frames)	OT had zero samples in the prefix

These prefixes have already been trimmed from the published .pt files. Each .pt records the trim amount in _contact_meta.trim_offset, and all frame indices in bad_frames.json are in post-trim coordinates. The original H5 recordings under data/motherboard/2026-05-11/ remain untouched in the recording-machine archive (not on HF).

Fixed at the source: future recordings use a data_collection.py recorder-side watchdog that (a) refuses to start an episode unless every active rigid body has streamed an OT sample in the last 2 s, and (b) auto-saves + ends an in-progress episode after 10 s of OT silence on any active body. The bug that produced these prefixes can no longer happen.

OT track loss mid-episode (the remaining ~0.9 %)

After trimming the prefixes, the rest of the ot_loss intervals in ../bad_frames.json are short (typically 1–3 s) mid-episode mocap dropouts. Per freeze_diagnose's cross-modal motion check, the gel pad is still healthy and the cameras still capture — only the OptiTrack solver lost the rigid body, usually because the operator's hand moved near the edge of the mocap volume / camera FOV.

The shipped bad_frames.json flags these as ot_loss_L / ot_loss_R and the example dataloader skips overlapping windows automatically when skip_bad_frames=True.

Mitigation for future recordings: keep the workspace centred in the mocap volume; add a fourth or fifth marker to each GelSight rigid body so the solver tolerates more occlusion; add a fourth OT camera if budget allows. None of these affect the current dataset retroactively — they're just guidance for follow-up recording sessions.

Other caveats

• Missing / dropped files on motherboard/2026-05-11:
  • episode_000 and episode_002 — short test recordings (8.8 s and 10.4 s) with no tactile contact on either sensor; intentionally excluded.
  • episode_001 — lost at recording time (HDF5 superblock never finalized when the writer was killed mid-write); intentionally absent.
  • The remaining episode IDs are non-contiguous as a result. Don't infer ordering from filename gaps.
• Lossy resize: the 128×128 view and tactile fields are downsampled from native 480×640. Native resolution is not preserved in this release.
• Single camera: only realsense/cam0/color is included in the processed/.../*.pt slice. The other two RealSense views (and depth streams) are recorded in the raw H5 archive but not exposed in processed/mode1_v1/.
• OptiTrack alignment: the per-step poses in .pt are nearest-neighbour matched to camera ticks. The full ~120 Hz pose streams are not preserved here.
• Contact metrics are opinionated: tactile_{side}_{intensity, area, mixed} depend on the chosen tau and the p01 reference strategy. If you want a different tau, you'll need to re-derive them from raw GelSight frames.

Roadmap

• More tasks — the registry in ../tasks.json will grow.
• LeRobot-format full-fidelity variant (lerobot/v1.0/) is planned. It will include all three RealSense color and depth streams, GelSight at native resolution (FFV1 lossless), full-rate OptiTrack pose tracks for all three rigid bodies, and HF-native browser previews. The current processed/mode1_v1/ slice will remain as a stable training-task view.