React / README.md
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README: document the estimated contact-force columns (force_*_normal_n / penetration_mm / target_pose), the 1 N/mm stiffness assumption, and the limits — the data shipped without a word about it
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metadata
license: cc-by-4.0
task_categories:
  - robotics
tags:
  - robotics
  - tactile
  - manipulation
  - multimodal
  - gelsight
  - realsense
  - motion-capture
  - world-model
  - human-collected
  - lerobot
pretty_name: React (Tactile-Visual Manipulation)
size_categories:
  - 100K<n<1M
configs:
  - config_name: motherboard
    data_files:
      - split: train
        path: data/motherboard/meta/**/*.parquet
  - config_name: pushT
    data_files:
      - split: train
        path: data/pushT/meta/**/*.parquet
  - config_name: all
    default: true
    data_files:
      - split: train
        path: data/**/meta/**/*.parquet

React — Multi-Task Tactile-Visual Manipulation

Dense, contact-rich, synchronized multimodal interaction data collected from human hands holding handheld GelSight tactile sensors (no robot arm). Intended for tactile-visual dynamics / world-model learning.

133 min · 240 k frames @ 30 Hz · 3× RGB + 2× GelSight + OptiTrack · 2 tasks

Rows are written at 30 Hz, but the tactile stream updates more slowly — see Tactile sampling rate.

Format — LeRobot-style video release

Each episode ships as 5 MP4 video streams (640×480, H.264) + a per-frame parquet of poses and contact metrics. This matches how LeRobot / DROID / Open X-Embodiment ship manipulation data: tiny on disk (whole dataset ≈ 4.8 GB without depth vs ~1 TB raw), random-access decodable, training-ready.

data/<task>/
├── calibration/                     # OptiTrack→camera extrinsics for this task
│   ├── T_mocap_to_cam_{left,middle,right}.json
│   ├── T_gel_to_rigid_{left,right}.json
│   └── calibration.json             # epoch, applies-to dates, RMSE, chain
├── videos/<date>/episode_NNN/
│   ├── view_left.mp4  view_middle.mp4  view_right.mp4    # 640×480 RGB
│   └── tactile_left.mp4  tactile_right.mp4               # 640×480 GelSight
├── meta/<date>/episode_NNN.parquet  # one row per frame (see below)
├── episodes.jsonl                   # one row per episode
├── segments.json                    # clean-segment index (no bad frames)
├── bad_frames.json                  # quality intervals per episode
└── previews/<date>/episode_NNN.mp4  # 1280×480 viewer-layout preview

parquet columns (per frame, aligned to video frame i)

Column Type Meaning
frame_idx / frame_index int 0…T-1, matches MP4 frame index
episode / episode_index str / int source episode key and its 0-based index within the task
task / task_index str / int task name and index (0=motherboard, 1=pushT)
timestamp float64 camera clock (s)
sensor_left_pose, sensor_right_pose list[7] OptiTrack world pose of each GelSight (xyz + quat wxyz)
object_pose list[7] OptiTrack world pose of the manipulated object (NaN where the object body was not tracked — e.g. all pushT)
tactile_{L,R}_{intensity,area,mixed} float32 contact metrics (computed at full 640×480)
tactile_{left,right}_is_new bool True when that row is a fresh tactile reading (not a repeat of the previous row)
source_h5_frame int index into the original recording

Decoded frames are RGB (standard decoder convention) for all five RGB streams.

estimated contact force (motherboard + pushT, 36 episodes)

There is no force/torque sensor on this rig — the demonstrator's hand holds the sensor, so demonstrated pose equals achieved pose and the usual "position error × stiffness" force channel does not exist. These columns are estimated from the GelSight images alone by photometric reconstruction (difference image → per-sensor RGB lookup table → Poisson integration → depth), then mapped to newtons by a calibration fitted on sphere presses of known load.

Column Type Meaning
force_{left,right}_normal_n float32 estimated normal force [N], ≥ 0, exactly 0.0 on no-contact rows
force_{left,right}_penetration_mm float32 F / k — how far a stiffness-k environment would be pushed in
force_{left,right}_target_pose list[7] that sensor's pose displaced F/k along the contact normal (quaternion carried through unchanged)
import numpy as np, pyarrow.parquet as pq
t = pq.read_table("data/motherboard/meta/2026-05-10/episode_000.parquet")
f   = t["force_left_normal_n"].to_numpy()                  # (T,)   newtons
obs = np.array(t["sensor_left_pose"].to_pylist())          # (T, 7) xyz + quat
tgt = np.array(t["force_left_target_pose"].to_pylist())    # (T, 7) the action

What "force-informed action" means, and how to train on it

A policy trained to output sensor_*_pose learns where to go. It cannot learn how hard to press, because in this data the two are the same signal: a human hand reached a pose, and whatever force resulted was never recorded as a separate command. Regressing that pose and replaying it on a compliant robot reproduces the trajectory and not the interaction — the same motion against a stiffer or differently-placed object produces a different force, and nothing in the demonstration says which force was intended.

force_*_target_pose is that missing command, written in the units a robot already accepts:

target = observed + (F / k) · n̂        n̂ = press direction of that sensor,
                                            R(q_row) @ gel_axis_in_rigid

It is the pose a stiffness-k impedance controller would have to be commanded in order to generate the estimated force F against a surface at the observed pose. Train the policy to output target_pose, deploy it as the setpoint of an impedance/admittance controller with the same k, and the controller produces both the reach and the press. This is the standard trick behind position-based force control; the only new part is that F came from the tactile images rather than from a load cell.

action      = tgt                      # what the policy predicts
observation = obs                      # where the sensor actually was
# free space: byte-identical, so this is a strict addition to the old target
assert np.array_equal(action[f == 0], observation[f == 0])

That identity is not a claim — it is checked element-wise over all 301,727 free-space rows of the release, maximum deviation 0.0, quaternions included. Nothing changes where nothing is touched, so a model trained on target_pose degenerates to the pose-only model in free space and differs only in contact.

Choosing k — it is your controller's number, not ours

k = 1.0 N/mm is a declared assumption, recorded in the parquet field metadata (twm.stiffness_n_per_mm) and in each <episode>.force.json, so a target pose is never uninterpretable. It is deliberately soft, and at that value the implied penetrations are larger than the gel is thick:

penetration at k = 1 inside the 4.25 mm gel?
p95 over all rows 5.78 mm no
p95 over contact rows 6.86 mm no
maximum 7.285 N → 7.285 mm no

8.84% of all rows exceed the gel thickness at k = 1. To keep penetration physically plausible you need a stiffer environment model:

  • k ≥ 1.37 N/mm — p95 over all rows inside the gel. This is the weakest of the three and the least useful: 62.8% of rows are free space, so a percentile over all rows is mostly a percentile of zeros.
  • k ≥ 1.62 N/mm — p95 over contact rows inside the gel. Use this one.
  • k ≥ 1.72 N/mm — even the hardest press inside the gel.

Recompute rather than rescale the shipped column, since the direction matters:

K = 1.62                                             # your controller's stiffness
n_hat  = (tgt[:, :3] - obs[:, :3])                   # F/k · n̂ at the shipped k=1
n_hat /= np.linalg.norm(n_hat, axis=1, keepdims=True) + 1e-12
my_target = obs.copy()
my_target[:, :3] = obs[:, :3] + (f / K)[:, None] * n_hat

Read this before using the numbers

  • Accuracy is rank-order within a group, not a certified absolute scale. Held out by press position the estimator scores ρ = 0.739 / MAE 1.23 N on its own calibration objects. On five public force-labelled datasets the same pipeline reaches ρ 0.775–0.986. It is reliable for how hard, relative to other frames; it is not a load cell. Do not report absolute newtons from this dataset as ground truth.
  • Forces saturate at 7.285 N. The calibration's isotonic stage clips at the hardest press it was fitted on, so 0.90% of samples sit exactly at that value. Treat the maximum as a floor, not a measurement, and consider masking rows at the ceiling out of a regression loss.
  • Duplicate tactile rows repeat the previous estimate. The GelSight stream is slower than 30 Hz; rows with tactile_{side}_is_new == False carry the previous frame's force unchanged (forward fill, asserted exact). Filter on is_new if you need independent samples — and note that a force derivative computed without that filter is zero on ~72% of rows by construction.
  • Row alignment is verified, not assumed. Every one of the 72/72 sensor-sides was checked row-for-row against the release parquet it was exported from.
  • The direction comes from calibration, not from the image. It is the sensor's gel axis rotated by the row's own quaternion. Two sensor-sides of 72 lack a usable gel-to-rigid transform and carry force with no displacement; they are identified in data/force_export_manifest.json.

depth (optional, data/<task>/depth/)

Per-camera depth is shipped as lossless FFV1 16-bit video (gray16le):

data/<task>/depth/<date>/episode_NNN/depth_{left,middle,right}.mkv
  • uint16, millimeters; 0 = no return / invalid.
  • Frame i aligns to the RGB video frame i and parquet row i.
  • Decode with PyAV (frame.to_ndarray()(480, 640) uint16). cv2 cannot read 16-bit video.
  • Load via ReactVideoDataset(..., load_depth=True).

Tasks

Task Episodes Dates Duration Clean segments Calibration
motherboard 32 2026-05-10/11/19 108 min 76 (107 min) May-12 (RMSE ~5 mm)
pushT 4 2026-06-18 25 min 17 (25 min) June-26 (RMSE ~0.6 px)

See tasks.json for the machine-readable registry (per-task dates, sensors, calibration epoch, world-frame offsets).

Calibration epochs

Cameras were recalibrated between tasks. Each task points to the calibration valid for its recordings:

  • motherboardMay-12 extrinsics (data/motherboard/calibration/)
  • pushTJune-26 extrinsics (data/pushT/calibration/)

Camera extrinsics are used only for the projection overlay; stored poses are OptiTrack world-frame and independent of calibration. The 2026-05-19 motherboard session had a redefined world origin; an offset (0.23, 0, 0.175) m is already baked into its poses so all dates share one frame (recorded in episodes.jsonl).

Downloading — depth is optional

The dataset splits into a lightweight core (RGB + tactile + poses, ~4.8 GB) and an optional depth tree (data/<task>/depth/, ~33 GB lossless). Depth lives in its own subtree so you can skip it entirely.

from huggingface_hub import snapshot_download

# Core only — RGB + tactile + parquet, NO depth (~4.8 GB)
snapshot_download("yxma/React", repo_type="dataset",
                  ignore_patterns=["*/depth/*"])

# Everything including depth (~39 GB)
snapshot_download("yxma/React", repo_type="dataset")

# One task only
snapshot_download("yxma/React", repo_type="dataset",
                  allow_patterns=["data/motherboard/*"], ignore_patterns=["*/depth/*"])

Or use the helper: python examples/download.py --no-depth (see examples/download.py).

The ReactVideoDataset loader never touches depth unless you pass load_depth=True, so depth-free training requires no depth download.

Loading

from examples.react_video_dataset import ReactVideoDataset

ds = ReactVideoDataset("data/motherboard", window_length=16, mode="segment")
sample = ds[0]
# sample["view_middle"]:       (16, 480, 640, 3) uint8 RGB
# sample["tactile_left"]:      (16, 480, 640, 3) uint8 RGB
# sample["sensor_left_pose"]:  (16, 7) float32

mode="segment" iterates clean spans (no bad frames by construction); mode="window" slides over whole episodes and skips bad_frames.json intervals. Backend: PyAV (install decord for faster random access).

✅ Tactile latency corrected (was ~15 frames)

Recordings up to and including 2026-06-18 HAD a GelSight-vs-camera capture lag of ≈15 frames (~0.5 s): the tactile stream at index i was physically captured ~15 frames before the camera/pose at the same index. Cause: a recording-side cv2.VideoCapture V4L2 buffer that was never flushed (throttled reads + no BUFFERSIZE=1 + default pixel format). Fixed in the rig on 2026-06-27; future recordings will not have this lag.

The streams are stored frame-aligned by tick index, so this lag is baked in but now corrected in the published data (tactile shifted +15f, rebuilt from raw H5). No loader flag needed. The loader still accepts tactile_latency= for raw data:

ds = ReactVideoDataset("data/motherboard", tactile_latency=15)  # pairs view[i] with tactile[i+15]

tactile_latency shifts both the tactile videos and the tactile contact-scalar columns; poses/views/depth are unchanged. Set tactile_latency=0 for the raw (uncompensated) data. The exact per-session value should be re-measured with camera_stream/measure_gelsight_latency.py.

Tactile sampling rate (read this before training on touch)

Parquet rows and all five videos are written at 30 Hz, but the GelSight stream does not carry 30 Hz of information. Measured across the whole release:

value
tactile rows 480 080 (2 sensors × 240 k frames)
genuinely distinct tactile frames 135 297
duplicated rows 71.8 %
effective tactile rate ~8.5 fps
longest frozen stretch 30 frames (1.0 s)

Two causes, one fixed:

  1. Sensor ceiling — the GelSight Mini streams 3280×2464 MJPG at 18.75 fps. Some duplication against a 30 Hz row clock is unavoidable (~40 %).
  2. Recording-side decode backlog (all currently published data) — the rig decoded each full 8 MP frame on the capture thread (~71 ms), so tactile effectively ran at ~8 fps and every frame was reused ~3.6×. Fixed on the rig on 2026-06-27 (reduced-scale decode + per-sensor capture timestamps); recordings from that date on reach the 18.75 fps ceiling.

Use the flags. Every row carries tactile_left_is_new / tactile_right_is_new:

df = pq.read_table("episode_000.parquet").to_pandas()
fresh = df[df.tactile_left_is_new]     # 8.5 fps of real readings

Training tactile dynamics on all rows teaches the model that touch mostly does not change; it does, we just sampled it slowly. Visual and pose streams are unaffected — those are genuinely 30 Hz.

The flags were recovered from the shipped contact metrics (a repeated frame gives a bit-identical metric triple) and checked frame-by-frame against the source recordings: 0 mismatches over 899 frames on each of 7 audited episodes, spanning both tasks. The same check independently recovers the +15-frame latency correction baked into the release.

How to use this dataset

Three recipes, in the order most people need them. Every one is executed against the published files by scripts/test_readme_recipes.py, so the code below is code that runs, not code that reads well.

1. Sample training clips — start from segments.json, not from episodes

An episode is a raw recording and contains flagged frames. A segment is a contiguous span that is already clean. Sampling clips from episodes means re-deriving the quality filter yourself and getting it slightly different.

import json, numpy as np, pyarrow.parquet as pq

segs = json.load(open("data/pushT/segments.json"))["segments"]
s = segs[0]                                     # {'source_episode', 'frame_range', ...}
date, ep = s["source_episode"].split("/")
a, b = s["frame_range"]                         # inclusive, in VIDEO frame coords

t = pq.read_table(f"data/pushT/meta/{date}/{ep}.parquet").slice(a, b - a + 1)

frame_range indexes the published MP4s and the parquet with the same origin, so frame i of view_middle.mp4 is row i of the parquet. No offset, no lookup table.

2. Train on touch — respect the tactile rate

Rows are written at 30 Hz; the GelSight stream is slower. A row with tactile_{side}_is_new == False repeats the previous tactile frame, its contact scalars, and its force estimate, unchanged.

new = t["tactile_left_is_new"].to_numpy()
# independent tactile samples only
idx = np.flatnonzero(new)
# a finite difference over ALL rows is 0 wherever is_new is False, by construction

Roughly 72% of rows are repeats. Ignoring this does not corrupt a model that consumes frames independently, but it silently zeroes any temporal derivative of a tactile channel and inflates any "how often does touch change" statistic.

3. Train an action that includes how hard

This is the part that distinguishes React from a pose-only demonstration set, so it gets its own section: estimated contact force. In short:

observation = np.array(t["sensor_left_pose"].to_pylist())        # where it was
action      = np.array(t["force_left_target_pose"].to_pylist())  # where to push to

action equals observation exactly in free space and leads it by F/k along the press direction during contact. Train on action, deploy through an impedance controller of stiffness k, and the policy commands both the reach and the press. Read that section before choosing k — the shipped k = 1 N/mm is a declared assumption and a soft one.

What this dataset is not

  • No robot. A human hand holds each sensor. There are no joint angles, no gripper state, and no action in the robot-command sense other than the force-informed target pose described above.
  • No force sensor. Every newton in these files is estimated from tactile images. It is calibrated and validated, and it is still an estimate — see the limits in the force section before reporting absolute values.
  • Not a benchmark. There is no train/val/test split and no success label. It is interaction data for dynamics and representation learning.

Data quality

Per-task bad_frames.json marks intervals that should not be trained on, and segments.json is their complement — contiguous clean spans, already excluding every flag below. Use segments.json and you never have to think about this table.

flag motherboard pushT
cam_corruption 0 0
intensity_spikes 56 10
ot_loss_L 1,443 106
ot_loss_R 236 191
pose_teleports_L 24 0
pose_teleports_R 16 0
tactile_corruption 102 10
flagged (union) 1,797 / 194,445 (0.92%) 307 / 45,595 (0.67%)
clean segments 81 spans, 192,626 frames (107.0 min) 17 spans, 45,288 frames (25.2 min)
dropped, clean but < 16 frames 22 0

The three rows above reconcile exactly: flagged + clean + dropped = total, for both tasks. Per-flag counts do not sum to the flagged total, because one frame can trip two detectors; the union is what summary reports and what the segments complement.

ot_loss_* is OptiTrack track loss (a run of bit-identical poses, i.e. frozen action), pose_teleports_* an implausible jump in translation and rotation in one frame, intensity_spikes a GelSight reading above anything contact produces. tactile_corruption and cam_corruption are video defects — torn frames the sidecar scalars cannot see. They are found by looking for off-illumination magenta laid out in scanlines: a GelSight is lit by three coloured LEDs, magenta is outside that gamut, and a corrupt row is written edge to edge while an object pressed into the gel is not. Every flagged interval in this release was also inspected by eye.

Runt episodes. Two motherboard recordings are far too short to be complete demonstrations and are best filtered out: 2026-05-19/episode_003 (4.0 s) and 2026-05-19/episode_004 (7.0 s). Median episode length is 213 s; these two are together 0.8 % of the release. They are shipped rather than deleted so episode numbering stays stable.

A missing pushT episode. pushT/2026-06-18/episode_004 was recorded but is not published. Its recorder died without closing the file, which loses HDF5's metadata cache: 79 GB of intact pixels behind a root object header that was never written. All eight image streams were recovered (15,447 frames, byte-verified), but only 2 of 16 timestamp chunks survived and no usable OptiTrack poses. Without timestamps there is no cross-modal alignment, and reconstructing them by interpolation misplaces frames by 15–1431 — so it is video, not an episode, and is deliberately absent rather than published half-aligned. Episode numbering is unaffected: pushT publishes 000–003.

Notes

  • Depth is published, under data/<task>/depth/<date>/<episode>/depth_*.mkv (16-bit millimetres, FFV1-in-Matroska, lossless). It is 34.3 GB of the 39.0 GB repo, so the download recipes above let you skip it — everything else is 4.8 GB.
  • The previous single-task .pt release (episodes/, segments/) is superseded by this video format.
  • Preview clips under data/<task>/previews/ are 30 s renders at 2x with the three camera views, the OptiTrack skeleton, both GelSight streams and the projected sensor position. They are for looking, not for training, and frames excluded by bad_frames.json are outlined and named in red.

License

CC-BY-4.0.