Concise dataset card, demos, DETAILS.md

DETAILS.md

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+
+# ForceBody: dataset details
+
+Release 1.3.0 (2026-10-29).
+
+ForceBody pairs the SKEL body model with measured ground reaction forces (GRF), inverse-dynamics joint torques and Monte Carlo torque uncertainty for 10,386 motion trials (9,689,808 frames, 26.89 h; duration = `num_frames` / `fps`) of 140 persons (75 male, 55 female, 10 sex not reported) from 10 studies (AddBiomechanics). Every trial is one NumPy `.npz` file; no nimblephysics, OpenSim or AddBiomechanics tooling is needed to read it.
+
+Since version 1.2, ForceBody ships two SKEL pose sets per trial (one fitted to the kinematics-only AddBiomechanics pass, one to the force-aware dynamics pass), cleaned GRF, recomputed torques and uncertainty for every trial, one body shape per person, corrected metadata, frame-level quality masks, and fixed splits. Read "Choosing a pose source" and "Leakage policy" before training anything that predicts or scores forces.
+
+| study | persons | trials |
+|---|---|---|
+| Carter2023 | 50 | 7,006 |
+| Falisse2017 | 11 | 70 |
+| Fregly2012 | 4 | 78 |
+| Hamner2013 | 10 | 40 |
+| Han2023 | 7 | 240 |
+| Li2021 | 1 | 65 |
+| Moore2015 | 12 | 1,019 |
+| Tiziana2019 | 25 | 619 |
+| Uhlrich2023 | 10 | 160 |
+| vanderZee2022 | 10 | 1,089 |
+| total | 140 | 10,386 |
+
+Study ids follow the first author and year of the source study (`study_citation` gives the citation key; Tiziana2019 = Lencioni et al. 2019). Release 1.3.0 renamed Hammer2013 to Hamner2013 (Hamner and Delp 2013): the 40 trial keys, folders and person ids changed (`uid_map_v12_to_v13.csv`, manifest column `trial_uid_v12`). Fields that point into the AddBiomechanics source (`b3d_path`, `subject_id_raw`, `trial_uid_v1`, the `models/` file names) keep the AddBiomechanics folder spelling Hammer2013.
+
+## Layout
+
+This Hugging Face repository holds the data only. The loader (`forcebody_io.py`), the renderer (`visualize.py`, `VISUALIZATION.md`), the benchmark card, cache builder and scorer (`benchmark/`) and the baseline code are in the GitHub repository https://github.com/DominoAI-Lab/ForceBody-NeurIPS-ED-2026. The v1.1 provenance files and the Monte Carlo torque percentiles are not part of this upload.
+
+```
+ForceBody_release_v1.3/
+  trials/<study>/S<NN>/<trial_uid>.npz        core arrays, 547 fields (SCHEMA_v1.3.csv)
+  manifest.csv, manifest_train.csv, manifest_test.csv   one row per trial (every scalar field + metadata)
+  uid_map_v12_to_v13.csv                     the 40 trial keys and paths renamed in 1.3.0 (Hammer2013 -> Hamner2013)
+  name_map.csv, name_map.json                trial_uid -> AddBiomechanics source file and trial (`split` = the AddBiomechanics source split, not split_addb)
+  persons.csv                                one row per person: betas, sex, height, masses, SHAPY measures, splits
+  subjects.csv                               per-person metadata table (v1.1 layout, v1.2 values)
+  gait_events.csv                            GRF heel strikes and toe-offs (walking / running)
+  models/                                    AddB pass-0 and pass-2 scaled OpenSim models per b3d file (.osim.gz),
+                                              body_segments.csv (segment masses, local COM)
+  marker_vertex_map.json                     marker name -> SKEL skin vertex used by the fit
+  SCHEMA_v1.3.csv                            field, dtype, shape, unit, frame, version_added, description
+  README.md, CHANGELOG.md
+```
+
+## Choosing a pose source
+
+Each trial has two SKEL fits. Both have every field and every QC mask; pick one with `pose_source`.
+
+| `pose_source` | fields | fitted to | default use |
+|---|---|---|---|
+| `pass0` (alias `kin`) | `poses`, `trans`, `joints`, `q_kin`, `qd_kin`, `qdd_kin`, `addb_joints_kin` | AddB kinematics pass (pass 0) + 30 Hz 2nd-order Butterworth filter (= AddB pass 1); never saw the force plates | force and torque estimation, physics critics p(tau \| motion), any metric that scores forces from motion |
+| `pass2` (alias `dyn`) | `poses_dyn`, `trans_dyn`, `joints_dyn`, `q_gt`, `qd_gt`, `qdd_gt`, `addb_joints_dyn` | AddB dynamics pass (pass 2); consistent with the GRF and torque labels | text-to-motion (motion only, or motion + GRF + torque), T2M evaluators |
+
+```python
+import forcebody_io as fio
+d = fio.load_trial("trials/Moore2015/S10/Moore2015_S10_walk_014.npz", pose_source="pass0")
+# common keys: poses, trans, joints, q, qd, qdd, addb_joints, pose_usable, pose_source
+# plus every GRF / torque / mask / metadata field of the file
+```
+
+`pose_source` is required (`ValueError` otherwise). `pose_usable` is always True for `pass0` and equals `poses_dyn_usable` for `pass2` (False in 15 trials: force/motion-capture desync). What pass 2 changes (AddB documentation and our audit): AddB moves the pelvis so the centre-of-mass path matches the measured GRF, then refits poses and body scales. COM-GRF Newton consistency improves (r 0.9947 -> 0.9998), but stance-foot sliding rises (0.064 -> 0.079 m/s) and the p90 marker error rises (26.8 -> 36.0 mm). Joint centres differ by a median 9.6 mm, mostly a constant bone-rescaling offset. Pass 2 also changes the motion on the 11.7% of frames without GRF.
+
+Re-timed trials (27; `skel_fit_target_dyn == "kin_retimed"`): the force stream was shifted in time to match the motion capture (`grf_retimed_ms`). Their pass-2 fit had been bent to the misaligned force, so `poses_dyn`, `trans_dyn`, `joints_dyn` and `addb_joints_dyn` equal the pass-0 fields, `q_gt`, `qd_gt`, `qdd_gt` and `tau_gt_det` are not usable (`q_gt_usable`, `tau_gt_det_usable` False), and `tau_selfconsistent`, `mu_tau` and `sigma_tau` are computed on `q_kin` with the pass-2 skeleton (`tau_sc_kinematics`, `mc_kinematics`). `load_trial(..., "pass2")` returns `q_kin` as `q` for these trials (`q_source`).
+
+## SKEL fit versions and fix rounds
+
+Both pose sets come from one refit code base that went through several fix rounds before this release. `skel_fit_code_version` / `skel_fit_code_version_dyn` and `skel_fit_source_run` / `skel_fit_source_run_dyn` record per trial which code produced each fit.
+
+| fit | code version | trials |
+|---|---|---|
+| `poses` | v1.2-fixround-2026-10-03c | 10,291 |
+| `poses` | v1.2-fixround-2026-10-04d | 95 |
+| `poses_dyn` | v1.2-fixround-2026-10-03c | 8,940 |
+| `poses_dyn` | v1.2-fixround-2026-10-07e | 9 |
+| `poses_dyn` | v1.2-fixround-2026-10-08i | 815 |
+| `poses_dyn` | v1.2-fixround-2026-10-09l | 622 |
+
+What the rounds changed (all trials unless a count is given):
+
+- scapula: the right scapula elevation bound of SKEL `kin_skel.py` has the wrong sign; it is replaced by the mirror of the left bound ([0.1, 0.4] rad). The bound sizes (0.1, 0.4 rad) have no published source (SKEL issue #19) and elevation sits on them in many fits (see Known issues).
+- marker handling: aliases for trunk / shoulder markers (Han2023, Uhlrich2023) and acromion vertices moved to the acromion tip (`marker_vertex_map.json`).
+- kinematics target (`q_kin`): where the AddB pass-0 left arm parks on its joint limit or hops (> 30 deg per frame) and where the elbow parks at 0, the arm is re-solved by inverse kinematics to the markers before the 30 Hz filter; a window is kept only if the marker error does not rise (hop windows: by at most 1 mm). 875 trials (`q_kin_source == "addb_pass0_armfix_lp30"`). Inside full-body hop windows the leg and trunk target also changes.
+- fit: a continuity guard repairs fit-only branch flips of arm, leg and root DOF groups; Stage-2 joint weights of femur and tibia raised from 5 / 3 to 10 (our choice) so the knee follows the target; an extra lower-body stage (2f) is kept when it passes the whole-body error gate. Trade-off: the pelvis joint error rises (median about 2 mm) because the SKEL femur is shorter than the AddB femur.
+- head: the head is pinned during the main fit and fitted afterwards to the head markers (orientation only, neck limits of bsm.osim). 1,948 trials have `head_postfit`; the others (`qc_head_untracked`) keep head DOFs 23-25 at 0, so the head follows the thorax.
+
+### Dynamics-pass target repair (`poses_dyn` is not pure pass 2 everywhere)
+
+`poses_dyn` is fitted to the AddB dynamics pass (`q_gt`) except where that target was repaired. `skel_fit_target_dyn` names the target, `dyn_target_source [T,37]` marks per frame and AddB DOF which values replaced `q_gt` (0 = pure pass 2), `dyn_target_modified_frac` is the fraction of modified frames, and `addb_joints_dyn` are the joint centres of the target actually fitted. `q_gt` itself is unchanged, so in the flagged frames `poses_dyn` and `q_gt` disagree.
+
+| `skel_fit_target_dyn` | trials | target |
+|---|---|---|
+| `addb_pass2` | 8,939 | pure pass 2 (`q_gt`) |
+| `addb_pass2_armsplice` | 9 | pass 2 with the kinematics-target (re-solved) arm spliced in inside the accepted arm windows, cosine ramps |
+| `addb_pass2_repaired_v3a` | 791 | pass 2 with the kinematics target (whole body, aligned at the window edges) in frames without valid GRF, the kinematics root on GRF-valid frames where the pass-2 pelvis deviates by more than 50 mm, kinematics values on pass-0 IK outlier frames, left-arm splice; 0.25 s cosine ramps |
+| `addb_pass2_repaired_v4s` | 620 | v3a plus a position-based left-arm IK on the pass-2 skeleton and the AddB acceleration-minimizing filter on all 37 DOFs (removes 6-30 Hz wobble of pass 2) |
+| `kin_retimed` | 27 | `poses_dyn` = `poses` (re-timed trials, below) |
+
+Bits of `dyn_target_source`: 1 kinematics value (GRF-invalid window or pass-2 root deviation), 2 left-arm splice, 4 pass-0 IK outlier repair, 8 left-arm position IK, 16 acceleration-minimizing filter, 32 other difference from `q_gt` (arm splice). 1,392 trials have a modified frame (median modified fraction 0.83); 1,048,169 of 9,689,808 frames. `dyn_arm_spliced [T,2]` marks frames whose dyn-target arm comes from the kinematics or IK arm (622 trials, `qc_dyn_arm_spliced`). The repair trades Newton consistency for a plausible root and arms where pass 2 had no force support: on the repaired trials the root path follows the kinematics target in GRF-invalid windows, so GRF-free frames of `poses_dyn` are no longer force-aware there. For a force-aware motion source with the arm and root fixes, use `poses_dyn` with its masks; for pure AddB pass-2 kinematics use `q_gt`.
+
+## Leakage policy
+
+AddBiomechanics warns: "If you use the output of the dynamics pass, you will be training your model on data that has already been fine tuned to match the force plate data, and your model will overfit to the clues that the optimizer inserts into the motion", and for GRF prediction to "use as input features only the kinematics pass" (nimblephysics documentation, working with AddBiomechanics data). GaitDynamics uses the kinematics pass "to prevent the leakage of force data ... into the kinematics"; InferBiomechanics (AddB benchmark code) takes inputs from the kinematics pass and labels from the last pass.
+
+How large the effect is here: recovering the total GRF from the centre-of-mass acceleration alone, with no learning, has a median error of 2.56 N/kg on pass-1 kinematics and 0.2 N/kg on pass-2 kinematics.
+
+Rule (an allowlist): a model that predicts or scores forces or torques may take as input only the pass-0 pose set (`poses`, `trans`, `joints`, `q_kin`, `qd_kin`, `qdd_kin`, `addb_joints_kin`, or `load_trial(..., "pass0")`), `betas`, `skel_gender`, `mass_kg`, `height_m`, `sex`, `age` and person-free text metadata (`forcebody_io.ALLOWED_INPUT_FIELDS`). Every other field is excluded, in particular the dynamics-pass pose set (`poses_dyn`, `trans_dyn`, `joints_dyn`, `addb_joints_dyn`, `q_gt`, `qd_gt`, `qdd_gt`), the labels (`tau_*`, `mu_tau`, `sigma_tau`, `percentiles`, `grf*`, `cop*`, `contact_*`, `grf_valid_mask`) and the fields derived from the GRF: `mass_kg_grf`, `mass_dyn_scale`, `mass_kg_dynamics*`, `cadence_spm_grf`, `stride_time_s_med`, `duty_factor_*`, `gait_events.csv`, `support_side`, `support_side_grf_share`, `caption_support_side`, `floor_height_m`, `speed_belt_grf_mps`, `mc_frame_ok`, `eval_*`, `s8b_*`, the usability flags, the `qc_*` fields and every `*_dyn` / `dyn_*` field (`dyn_target_source` is placed by the GRF-valid windows). `forcebody_io.LEAKY_INPUT_FIELDS` lists these as a safety net; the benchmark loader refuses them and any input that is not a benchmark input. Results computed with `pass2` inputs must be labelled leaky and are not comparable with the official benchmark numbers. The body shape (`betas`) was fitted to pass-0 bone lengths, the recorded height and a person mass target; for Moore2015 that target is the GRF calibration-pose mass (a static, person-level weight).
+
+## Force benchmark
+
+The force benchmark (joint torques T-tau and per-foot GRF T-GRF from motion) is defined in `code/benchmark/BENCHMARK.md` of the GitHub repository https://github.com/DominoAI-Lab/ForceBody-NeurIPS-ED-2026 with the machine-readable `benchmark/spec_v12.json`, a cache builder (`benchmark/build_bench_cache_v12.py`) and the reference scorer (`benchmark/score_v12.py`). The scripts import `forcebody_io.py` from the release root. BENCHMARK.md lists the split sizes and the baselines retrained on 1.2.1 (5 torque models and the GRF MLP; 3 torque models pending). The benchmark data of 1.3.0 are identical to 1.2.1 except the 40 renamed Hamner2013 keys.
+
+## Conventions
+
+| item | convention |
+|---|---|
+| frames | `addb_lab`: raw AddB lab frame, y up (grf, cop, contact_torque, markers, q_*, tau_*). `skel_world`: `flip_xz(addb_lab)` (x -> -x, z -> -z, y unchanged): poses, trans, joints, addb_joints_*, *_aligned, cop_aligned_foot. Every `*_aligned` field is exactly `flip_xz` of its raw field (max difference 0) |
+| gravity | -y in every study |
+| contacts | index 0 = right foot (calcn_r), 1 = left foot (calcn_l), 2 = pelvis (Falisse2017 chair) |
+| trans | SKEL root translation (`trans_frame == "skel_world"`). The pelvis joint is `trans + j0(betas)`, not `trans`; j0 is about (0.0095, -0.236, 0.103) m for a male rest pose, so rotating `trans` alone misplaces the body by 0.12-0.16 m |
+| joints | `joints[T,24,3]` in `joint_names` order (SKEL / OpenSim: 0 pelvis, 1 femur_r, ...) |
+| DOF names | `skel_pose_names` (46 SKEL pose DOFs; `skel_dof_valid` False = pinned to 0 in the fit), `dof_names_opensim` (37 AddB DOFs, OpenSim Rajagopal coordinate names and sign conventions) |
+| time | `t_i = i / fps_true_grid`. `fps` is the nominal rate; the true grid differs slightly (61 Hz: 64, 99 Hz: 470, 100 Hz: 9,640, 101 Hz: 76, 201 Hz: 111, 250 Hz: 25 trials by rounded rate) |
+| heading | use `heading_canonical_deg` (SKEL frame) only |
+| mirroring | swapping left/right SKEL DOFs with a sign table is not an exact mirror (MPJPE 32 mm, feet 45-77 mm); mirror the mesh or the joint positions instead |
+
+## Body mass fields
+
+| field | meaning | use |
+|---|---|---|
+| `mass_kg` | recorded mass (unchanged from v1.1) | model and critic inputs |
+| `mass_kg_dynamics` | AddB pass-2 skeleton mass times `mass_dyn_scale` (already applied) | the only mass for normalizing GRF, torque and sigma labels (N/kg, N m/kg, BW) |
+| `mass_kg_dynamics_v11`, `mass_dyn_scale` | v1.1 dynamics mass and the approved per-file rescale | provenance. Never multiply `mass_kg_dynamics` by `mass_dyn_scale` again. `mass_kg_dynamics_v11` stays in the core file (the only `_v11` value there besides the QC count `qc_grf_endpoint_valid_v11`) |
+| `mass_kg_grf` | per-trial GRF-implied mass estimate | diagnostic |
+| `caption_mass_kg`, `shape_mass_target_kg`, `mass_source` | person mass for captions and for the shape fit (recorded; Moore2015 = GRF calibration pose) | text, shape |
+
+`mass_dyn_scale` differs from 1 in 491 trials (14 b3d files), where the AddB link masses were inconsistent with the measured GRF.
+
+## Quality masks
+
+Nothing is deleted; problems are flagged. Frame masks (`[T]` or `[T,2]`): `grf_frame_ok` (GRF validity: GRF losses and statistics), `grf_frame_strict_ok` (whole frame without zero-force or misassigned feet), `grf_foot_ok` (per foot, columns right, left; 1.2.1), `tau_frame_ok` (torque losses), `mc_frame_ok` (use of sigma_tau), `kin_frame_ok` (pelvis not flipped), `cop_frame_ok` (per foot), `grf_contact_state` (per foot: 1 = in contact on a `grf_frame_ok` frame, 0 = not in contact on a `grf_frame_ok` frame, -1 = unknown: no measured force, or a measured frame outside `grf_frame_ok`), `eval_tau_frame_ok` (= `tau_frame_ok` and `kin_frame_ok`), `eval_grf_frame_ok` (= `grf_frame_ok` and `kin_frame_ok`).
+
+GRF validity and CoP trust (1.2.1). `grf_frame_ok` is GRF validity only: `grf_valid_mask`, not an endpoint or a blanked tail, and a consistent force label on every used contact (`grf_contact_ok`). A loaded contact with `contact_status` 3 (force valid, CoP projected on the foot and not trusted) counts as valid. CoP trust gates only `cop_frame_ok` (trusted CoP status 1, 2 or 9 on that foot) and `tau_frame_ok` (no used contact with status 3, because the torque depends on the CoP). In 1.2.0 the status-3 frames were not in `grf_frame_ok`, so on fixed-point-CoP trials (`qc_cop_fixed_point`, Carter2023) the GRF masks kept only unloaded frames (CHANGELOG, erratum); in 1.2.1 170,158 status-3 frames of 1,158 trials are in `grf_frame_ok`. The QC scalars are still computed on `grf_frame_ok` without the status-3 frames, as in 1.2.0, so their values did not change, except the mask summaries (`grf_frame_ok_frac`, `grf_frame_strict_ok_frac`, `qc_grf_contact_bad_frames`) and the evaluation flags.
+
+Per-foot GRF mask (1.2.1). `grf_frame_strict_ok` drops the whole frame when either foot is zero-force grounded, force-in-air, unmeasured in stance or has its CoP off the foot. `grf_foot_ok` drops only the zero-force-grounded foot itself; the other three flags point to a likely plate misassignment (the force of the other foot may be on the wrong plate), so they still drop both feet of the frame (`grf_foot_ok.all(1)` equals `grf_frame_strict_ok`). It keeps 854,888 loaded foot-frames (vertical GRF > 20 N) that the strict mask removes.
+
+Masked values are not NaN: outside a mask the arrays keep their raw values. `cop` and `contact_torque` are 0 where the force is 0, the GRF of the AddB endpoint frames is 0, and `grf` / `grf_aligned` can be non-zero on frames outside `grf_valid_mask` (force readings that AddB marked as missing). A 0 is not a measurement; always apply the mask.
+
+Trial flags:
+
+| flag | trials True |
+|---|---|
+| `force_label_usable` | 10,372 |
+| `torque_label_usable` | 10,067 |
+| `eval_motion_trial_ok` | 9,697 |
+| `eval_grf_trial_ok` | 9,769 |
+| `eval_torque_trial_ok` | 8,256 |
+| `qc_pass2_equals_pass1` | 1,249 |
+| `qc_skel_grf_newton_mismatch` | 244 |
+| `qc_grf_single_channel` | 37 |
+| `qc_mass_dyn_vs_grf_flag` | 20 |
+| `qc_overlap_pair_drop` | 8 |
+| `qc_overlap_motion_drop` | 200 |
+
+Evaluation flags. `eval_grf_trial_ok` and `eval_torque_trial_ok` require usable force labels and exclude single-channel force plates (`qc_grf_single_channel`: one plate carries both feet, so per-foot GRF and the foot assignment of the torques are wrong; also excluded from `torque_label_usable`), byte-identical duplicates (`qc_duplicate_drop`), the Han2023 trimmed copies of a re-exported capture (`qc_overlap_pair_drop` = `eval_exclude_duplicate` and not `qc_duplicate_drop`), static calibration, transition and pause segments, and trials whose dynamics mass disagrees with the GRF-implied mass by more than 5% (`qc_mass_dyn_vs_grf_flag`); `eval_torque_trial_ok` also requires a root residual force of at most 0.1 BW. Since 1.2.1 both also require at least one loaded evaluation frame (`qc_grf_loaded_eval_frames` > 0: a foot vertical GRF above 20 N on an `eval_grf_frame_ok` frame; for torques also `qc_tau_loaded_eval_frames` > 0); 83 trials with usable force labels have none (most have `grf_valid_mask` False on every frame). `eval_motion_trial_ok` applies the same duplicate / segment exclusions and in addition drops one member of each overlapping Tiziana2019 capture pair (`qc_overlap_motion_drop`: the member with fewer GRF-valid frames). The Tiziana2019 pairs share no GRF-valid frame, so both members stay in force evaluation. Always combine a trial flag with its frame mask.
+
+`force_label_usable` is False where force and motion capture are out of sync and could not be re-timed (14 trials); every force, torque, MC, contact and CoP frame mask is then False. `qc_skel_grf_newton_mismatch` marks trials whose SKEL root path does not follow the GRF without any time-lag evidence; their force labels are kept. Pathological persons are never excluded; `eval_stratum` reports them separately. Every QC field is described in SCHEMA_v1.2.csv.
+
+Falisse2017 chair channel (contact index 2, `contact_bodies` = `pelvis`). `chair_contact` [T] marks the frames where the subject sits on the instrumented chair (the `grf_contact_label` hysteresis on the chair vertical force, not restricted to `grf_frame_ok`; most seated frames are outside `grf_valid_mask`), `qc_chair_channel_active` marks trials with any such frame, and `qc_extra_channel_zero` marks trials whose chair channel carries no force at all (walk, stairs). On those trials `grf_contact_ok[:, 2]` is False on every frame and `grf_frame_ok` ignores the channel. The trial-level manifest column `chair_contact` (protocol metadata) is a different field from the per-frame npz array of the same name.
+
+### Pose masks of the fix rounds
+
+These masks describe the SKEL pose sets (True = usable). Each exists for both pose sets (`_kin` = `poses`, `_dyn` = `poses_dyn`); AND them into the loss mask of the listed DOFs. Masks are dilated by 0.1 s (our choice).
+
+| field | shape | False on | trials with a False frame | frames |
+|---|---|---|---|---|
+| `arm_event_ok_kin` | [T,2] (left, right) | arm discontinuities (arm-jump diagnosis of 2026-10-07 and a re-scan of the final fits); arm DOFs | 272 | 231,278 |
+| `arm_event_ok_dyn` | [T,2] | same for `poses_dyn` | 316 | 217,726 |
+| `trunk_event_ok_kin` | [T] | AddB pass-0 trunk shake (class A3); lumbar / thorax DOFs 17-22 | 143 | 200,423 |
+| `trunk_event_ok_dyn` | [T] | same for `poses_dyn` | 155 | 200,116 |
+| `dyn_root_jump_ok` | [T] | pass-2-only whole-body jumps (class A6): drop the whole `poses_dyn` frame | 108 | 2,858 |
+| `fit_event_ok_kin` | [T,7] | temporal events of the final fit per joint group (`fit_event_groups`: pelvis, leg_r, leg_l, spine, head, arm_r, arm_l): fit-only spikes, spikes inherited from the target, one-frame DOF steps, and Euler branch flips (one-frame step > pi) | 1,820 | 251,010 |
+| `fit_event_ok_dyn` | [T,7] | same for `poses_dyn`, measured against its own (repaired) target | 1,808 | 254,087 |
+| `kin_hop_edge_frame_ok_r` | [T] | right-arm frames at a hop-window edge of the arm re-solve where two Euler branches are joined (`qc_kin_hop_edge_branch_blend`) | 3 | 75 |
+
+Also per trial: `addb_limit_mask_kin` / `addb_limit_mask_dyn` [T,11] (the fit target sits on an AddB joint limit; the dyn mask is the union of the pass-2 and pass-0 on-limit frames, `addb_limit_mask_names`), `qc_arm_event_classes_kin` / `_dyn` (diagnosis classes present), and the trial flags below. Where `qc_upper_body_unobserved` is True (no torso / arm marker at all, e.g. vanderZee2022 S09) the arm, trunk and head masks are False on every frame of both pose sets: the SKEL arms, trunk and head are unconstrained there.
+
+| trial flag | trials True | meaning |
+|---|---|---|
+| `qc_upper_body_unobserved` | 133 | no upper-body marker; arms / trunk / head masked |
+| `qc_head_untracked` | 8,438 | fewer than 2 head markers; head DOFs 23-25 are 0 |
+| `qc_kin_armfix_edge` | 20 | arm re-solve window-edge artefact of the kinematics target (frames in `arm_event_ok_kin`) |
+| `qc_kin_hop_edge_branch_blend` | 3 | hop-window edge joins two right-arm Euler branches |
+| `qc_upper6_rise10_kin` | 13 | upper-body joint error of `poses` rose by > 10 mm in the fix rounds (our threshold); arm-marker error is better in almost all; flag, not exclusion |
+| `qc_upper6_rise10_dyn` | 18 | same for `poses_dyn` |
+| `qc_heading_rms3_kin` | 3 | pelvis heading lost > 0.1 correlation and detrended heading RMS > 3 deg (our thresholds) |
+| `qc_heading_rms3_dyn` | 2 | same for `poses_dyn` |
+| `qc_dyn_arm_spliced` | 622 | `poses_dyn` arms follow the kinematics / IK arm in `dyn_arm_spliced` frames |
+| `qc_tau_sc_q_kin_pre_armfix` | 0 | re-timed trial whose torque labels were computed on `q_kin` before the arm re-solve (`mc_kinematics == "q_kin_pre_armfix"`) |
+| `qc_pose_wrap_n_kin` > 0 | 1 | Euler branch flip in `poses` (masked, not unwrapped) |
+| `qc_pose_wrap_n_dyn` > 0 | 1 | same in `poses_dyn` |
+| `qc_head_at_limit_frac_*` > 0.05 | 11 | head post-fit at a neck limit on > 5% of frames; do not use the head orientation there |
+
+Added in 1.2.1 (T2M audit; flags and masks only, no pose refit):
+
+| field | trials | meaning |
+|---|---|---|
+| `qc_q_kin_wrap` | 68 | `q_kin` (fit target of `poses`) beyond 2 pi on a shoulder DOF (an AddB Euler branch; `qc_q_kin_abs_gt_2pi_dofs`); the frames of that arm are False in `arm_event_ok_kin`, and in `arm_event_ok_dyn` on kin_retimed trials. Not unwrapped |
+| `knee_clamp_frame_kin` / `_dyn` [T,2] (right, left), `qc_knee_clamp_frac_*` | 4,870 (kin, any frame); 1,061 kin / 1,294 dyn above 10% of frames | SKEL knee on its 0 bound while the AddB target knee is flexed 3 deg or more (our threshold). Flag only; `forcebody_io.load_trial` returns the mask of the chosen set as `knee_clamp_frame` |
+| `qc_belt_speed_change` / `qc_belt_speed_change_suspected` | 4 / 8 | treadmill belt labelled constant whose speed changes in the trial (both pose sets / one pose set) |
+| `label_conflict_codes` contains SEGMENT_MOTION_MISMATCH | 28 | segment label and motion disagree (Carter2023 static-trial stand segments with a leg lift, Han2023 pause / sit / short action segments); labels and captions not changed |
+
+## Uncertainty
+
+`mu_tau` and `sigma_tau` ship in the core file for all 10,386 trials, the torque `percentiles` (with `percentile_values`) are kept in the internal v1.1 provenance archive and are not part of this upload; `has_uncertainty` is True for 10,382 (False: the trial is shorter than one period of the 6 Hz noise band, sigma is 0). `has_uncertainty_v11` (manifest) marks the 8,652 trials that had MC in the paper version. sigma_tau is the kinematic sensitivity of the torque to 1.6 deg band-limited joint-angle noise on `q_gt` (pass 2; `q_kin` on re-timed trials) with the measured GRF held fixed. It is not the uncertainty of `poses`, and not a label-reliability score. Normalize it by `mass_kg_dynamics` only, and use it only where `mc_frame_ok` and `torque_label_usable` hold. Per-trial ratios to the paper-version sigma have p5-p95 0.85-1.20. The sigma statistics of the paper use the trials with `has_uncertainty` and `grf_valid_frac` >= 0.5 (8,732 trials).
+
+## Time alignment
+
+| item | status |
+|---|---|
+| release grid | one grid per trial for kinematics, forces and MC (`fps_true_grid`) |
+| AddB endpoints | frames 0 and T-1 carry no GRF; they are never in `grf_frame_ok` |
+| duration | `duration_s` = `num_frames` / `fps` (nominal rate, v1 convention); the time span of the grid is (`num_frames` - 1) / `fps_true_grid`, about one frame shorter |
+| force/mocap re-timing | 27 trials re-timed and validated against independent marker-based gait events; applied shift median 277 ms (range -85 to 320 ms) |
+| partial invalidation | 1 trial(s): force invalid from `force_invalid_from_frame` |
+| lag diagnostics | `qc_grf_kin_toeoff_lag_ms`, `qc_grf_kin_onset_lag_ms`, `qc_grf_newton_seg_lag_ms`, `qc_cop_foot_shift_ms` (positive = kinematics later than force) |
+
+## Floor and gait events
+
+- `floor_height_m`: median centre-of-pressure height (SKEL frame, y) over trusted firm-stance frames (`contact_status` 1, foot vertical force > 0.5 BW of `mass_kg_dynamics`, `grf_valid_mask`); NaN with fewer than 30 such frames. It comes from the force plates. On stairs and step activities it is the height of the loaded step surface, not of the floor.
+- No floor normal is shipped. A plane fitted to the SKEL sole height over the CoP positions tilts by 2-3 deg on level treadmills (heel-to-toe roll). The QC fields `floor_tilt_x_deg` / `floor_tilt_z_deg` (plane through the firm-stance CoPs) and `floor_tilt_x_kin_deg` / `floor_tilt_z_kin_deg` (SKEL sole height at the same samples) are diagnostics only; protocol inclines are in `incline_grade_pct` / `incline_label`.
+- `gait_events.csv`: heel strikes (`grf_contact_state` 0 -> 1) and toe-offs (1 -> 0) of each foot on walking and running trials with usable force labels; `frame` on the release grid, `time_s = frame / fps_true_grid`. `stride_time_s_med` is the median same-foot heel-strike interval (0.4-2.5 s, strides with an unknown (-1) frame inside are not used), `cadence_spm_grf` = 120 / `stride_time_s_med`, `duty_factor_r` / `duty_factor_l` the median stance fraction of a stride.
+- Consistency gate: where `cadence_spm_grf` differs from the kinematic `cadence_spm` (metadata) by more than 10% (our threshold), `qc_gait_event_inconsistent` is True, the four GRF gait scalars are NaN and the trial has no rows in gait_events.csv (28 trials).
+- Carter2023 running: in most trials `grf_valid_mask` also covers the flight frames (median `grf_valid_frac` 1.00); in some trials AddB marks the flight frames as missing GRF, and there GRF labels, T-GRF scores and `grf_contact_state` (-1) cover stance frames only and strides that contain such frames give no GRF gait scalars. On fixed-point-CoP trials (`qc_cop_fixed_point`) every loaded frame has `contact_status` 3; since 1.2.1 these frames are in `grf_frame_ok` and `grf_contact_state`, so these trials have GRF gait events, but they stay out of `cop_frame_ok` and `tau_frame_ok`. (1.2.0 stated the opposite: its GRF masks kept only the unloaded frames of these trials; CHANGELOG erratum.)
+
+## Metadata
+
+Every metadata column is in manifest.csv and the per-trial ones also in each trial file; SCHEMA_v1.3.csv gives the definition of each column. Groups: identity and capture structure (`person_id`, `subject_base`, `capture_id`, `segment_index`, `n_segments_in_capture`, `segment_role`, `qc_overlap_of`, `eval_exclude_duplicate`), activity (`activity_name`, `activity_recovered`, `activity`, `activity_sequence`, `activity_modifier`, `gait_style`, `source_task`, `setting`, `setting_motion`, `path`, `support_side`), protocol (`protocol_condition`, `condition_key`, `speed_*`, `incline_*`, `belt_*`, `cadence_*`, `step_*`), person (`sex`, `age`, `bmi`, `health_status`, `health_detail`, `footwear`) and captions (`caption_*`). The measured values (`speed_mps`, `cadence_spm`, `step_width_m`) come from forward kinematics of the AddB model; the running treadmill speed uses GRF stance frames, and `support_side_grf_share` and `speed_belt_grf_mps` use the GRF (Leakage policy).
+
+## Body shape
+
+`betas` are fitted once per person (identical in all trials of a person, persons.csv) to the pass-0 bone lengths, the recorded height and the person mass target, and `skel_gender` selects the SKEL model (`skel_gender_source`: height_rule 10, sex_label 130 persons). persons.csv reports SHAPY-style measurements of the shaped mesh (height = |y(HeadTop 411) - y(HeelLeft 3466)|, mass = volume x 985 kg/m^3, chest / waist / hip girths at vertices 6489 / 3501 / 1210). The girths are almost fully determined by height and mass (R^2 0.987-0.994); 41 (female) / 52 (male)% of the betas variance is bone proportion that height and mass do not explain. Claims about body shape should stay at the height / mass level.
+
+## Splits
+
+The Hugging Face configuration loads `manifest_train.csv` (split `train`, which holds the `split_addb_val` train and val persons; select val with `split_addb_val == "val"`) and `manifest_test.csv` (split `test`).
+
+`split_addb` (force benchmark train / test, person level) with `split_addb_val` (validation persons drawn from the train persons), and `split_t2m` (text-to-motion train / val / test / patho, person level). No person is in two folds of one split.
+
+All three are drawn with a stratified, seeded person-level search (2026-10-09): test and val persons cover the height x body-mass tertile cells of the healthy persons and the bottom / top 10% of height and mass, use different studies within a cell where possible, and cover as many activities as possible, while train keeps every activity, study and body-size cell that any other fold has. Test and val persons are drawn only from persons with at least 90% usable trials (split_addb test and val also need at least 90% trials with `eval_grf_trial_ok`). Pathological persons are `split_t2m=patho` and keep their earlier `split_addb` (separate `eval_stratum`). `split_addb` therefore no longer equals the split shipped with the AddBiomechanics source data. Splits of earlier versions are not compatible: caches or checkpoints trained on an earlier split may contain current test persons.
+
+| split_addb | persons | trials |
+|---|---|---|
+| test | 19 | 914 |
+| train | 121 | 9,472 |
+
+| split_addb_val | persons | trials |
+|---|---|---|
+| test | 19 | 914 |
+| train | 109 | 8,374 |
+| val | 12 | 1,098 |
+
+| split_t2m | persons |
+|---|---|
+| patho | 5 |
+| test | 35 |
+| train | 83 |
+| val | 17 |
+
+The split_t2m walking test set has 4 persons with a body mass target of 85 kg or more; the running test set has 0 (running is not evaluable at high body mass).
+
+## Health status and sensitive information
+
+| health_status | persons | trials |
+|---|---|---|
+| TKA | 4 | 78 |
+| healthy | 135 | 10,243 |
+| stroke | 1 | 65 |
+
+The data include persons after total knee arthroplasty and after stroke (`health_status`, `health_detail`); this is health information. `trial_name` keeps the source names: 240 Han2023 names contain a capture date and the Fregly2012 names (trials: 78) contain subject initials. Ages range from 18 to 86 years (unknown in 200 trials). Do not attempt to re-identify persons.
+
+## Intended and out-of-scope uses
+
+Intended: research on motion-to-force and force-aware motion models, text-to-motion with physical labels, biomechanics method development. Out of scope: clinical decisions or diagnosis, identifying or profiling persons, and human mesh recovery from images or video (there are no images or video in ForceBody).
+
+## Paper numbers
+
+The paper tables (Tables 3, 4, 5, 14 and 15) were computed on the reviewed build with the v1 labels and are not reproduced by v1.1, 1.2 or 1.3; benchmark baselines retrained on 1.2.1 are in benchmark/BENCHMARK.md. The Table 3 AddB row used dynamics-pass (pass 2) kinematics as input (see Leakage policy). The torque labels themselves moved between versions: scoring the v1.1 `tau_selfconsistent` against the paper labels gives RMSE / MAE / PCC 0.287 / 0.087 / 0.721, the same order as the model errors, so numbers from different versions must not be mixed in one table.
+
+## Known issues
+
+- vanderZee2022: force-plate cross-talk remains after the plate re-zero (swing-foot readings depend on the other plate load); the root residual force is higher than in other studies.
+- Carter2023 downhill: AddB did not dynamics-process these kinematics; the root residual stays high and the torque labels are flagged. `grf_valid_mask_plate` is offered for GRF supervision.
+- Carter2023 trials whose raw plate CoP is unusable keep a fixed-point CoP (`qc_cop_fixed_point`, `qc_tau_cop_unreliable`); exclude them from CoP and torque evaluation. Their forces are valid: since 1.2.1 the loaded frames are in `grf_frame_ok`, while `cop_frame_ok` and `tau_frame_ok` exclude them.
+- Han2023 yoga / dance: a few extreme-torque frames of kinematic origin (`tau_frame_ok` excludes them).
+- vanderZee2022 S09 has no upper-body markers (`qc_upper_body_unobserved`); AddB pass 0 and pass 2 arms differ by about 200 mm there and the SKEL arms, trunk and head are unconstrained (masked).
+- The scapula DOFs are pinned at their bounds in most fits (`qc_skel_scapula_pinned`); scapula elevation sits on its +-0.1 rad bound (size unsourced, SKEL issue #19) in many kinematics fits. Mask scapula DOFs in losses.
+- SKEL left ankle axis (SKEL issue #45, kept upstream): `ankle_angle_l` / `subtalar_angle_l` are not the mirror of the right DOFs and the fit compensates with subtalar_l. Do not mirror motions by swapping L/R SKEL DOFs; compare left and right ankles with the AddB q (`q_kin`, `q_gt`). Read the poses with official SKEL (a SKEL with the issue #45 fix moves the left toes by about 22 mm at p95).
+- Joint-limit bounds of the fit are left/right asymmetric for shoulder_y and pro_sup (unsourced kin_skel values, kept).
+- Pelvis joint error is higher than in the first v1.2 fit (median about 2 mm) after the knee weight change; the SKEL femur is shorter than the AddB femur (shape-step limitation).
+- Head post-fit: a few trials sit on a neck limit for many frames (`qc_head_at_limit_frac_*`); trials without head markers keep the head rigid with the thorax (neck line 3-10 deg forward of the markers in head-marker studies).
+- Non-arm fit-only spikes (head, spine) exist in a minority of trials; they are masked per joint group in `fit_event_ok_*`, not repaired. Head post-fit steps > 0.5 rad per frame are masked in the head column.
+- Dynamics-pass target repair: on repaired trials the Newton consistency of `poses_dyn` with the GRF dropped by more than 0.02 (correlation) in a minority of trials and the lower-body error rose by more than 1 mm in some; accepted. `qc_skel_vs_qgt_err_mm` compares with `q_gt`, not with the repaired target.
+- Some dyn-pass arm events listed by the 2026-10-07 diagnosis refer to the dyn fit before the 2026-10-08/09 target repair; they are kept in `arm_event_ok_dyn` (conservative), together with the events of the re-scan of the final fits.
+- Carter2023 running: in some trials AddB marks the flight frames as missing GRF (`grf_valid_mask` False), so force labels and the T-GRF benchmark cover stance frames only there (most trials keep the flight frames valid with zero force).
+- `floor_height_m` is the loaded step height on stairs / step activities; no floor normal is shipped.
+- `visualize.py` needs the addb2skel package (SKEL rendering utilities), which is not distributed with ForceBody; reading the data needs only numpy.
+- Release verification left three small deviations: in one trial the fit joint error recomputed from the stored float32 `joints` / `addb_joints_kin` differs from the stored `qc_skel_fit_err_mm` by 0.054 mm (tolerance 0.05 mm, so one of 10,386 trials fails the independent reproduction check); the median lag between GRF and kinematic toe-off events is -74.5 ms for Uhlrich2023 (all other studies -50 to 0 ms), just outside the -70 to +10 ms window used as a sanity range.
+- No acceleration filter was applied to the kinematics-pass target: `poses` keep a small frame-to-frame wobble on trials whose AddB pass-0 inverse kinematics is noisy. The dynamics-pass target is smoother (AddB dynamics pass; repaired targets use the AddB acceleration-minimizing filter).
+- Name clash: `chair_contact` in manifest.csv is the trial-level protocol flag (a chair is used in the trial), while `chair_contact` inside the trial file is the frame-level [T] seated mask of the Falisse2017 chair channel (all False without a chair channel). Use `qc_chair_channel_active` for the trial-level summary of the frame mask.
+- CoP placement at low load: frames where a foot channel is loaded (vertical force above 5% BW) and its CoP lies more than 0.15 m from both feet are not all flagged. A scan of the release found 3,227 GRF-valid such frames in 664 trials with `cop_frame_ok` True and `cop_off_foot` False; mask CoP losses by load if this matters.
+- Han2023 `sit` (12 trials) and `sit-to-stand` (2 trials): in the frames a posture rule marks as seated, the foot GRF stays near 1 BW (median 0.999 BW) and there is no seat force channel, so either the seat load is not measured or the label does not describe a loaded seated phase. The labels were not changed.
+- Treadmill belt residual: on treadmill trials the stance foot is not perfectly stationary after the belt motion is removed with a kinematic estimate of the horizontal belt speed (and the protocol grade for the vertical component): the median stance-foot speed is about 0.05-0.10 m/s depending on the trial sample and pose set, against about 0.02-0.05 m/s overground.
+- SKEL knee clamped at full extension (T2M audit R11): in many walking trials the SKEL knee sits on its 0 bound while the AddB target knee is flexed about 3-8 deg, more often on the left. Flagged per frame in `knee_clamp_frame_kin` / `_dyn` since 1.2.1 (1,061 trials above 10% of frames in `poses`); not refitted. On kin_retimed trials `knee_clamp_frame_dyn` compares `poses_dyn` with `q_gt`, not with the retimed kinematic target.
+- Stairs (22 trials in activity class stairs): no per-step floor is shipped. `floor_height_m` is one loaded-step height per trial, and one fitted floor plane per trial (as in the T2M encoders) treats a staircase as a ramp, so heights above that floor are not step-relative (T2M audit R15).
+- Moore2015 standing (29 trials): in the wide-stance phases the feet sit 2-4 cm below the trial median floor level on about 40% of frames; whether this is real penetration or a floor estimate set too high is not resolved (T2M audit R18).
+- Pathological persons (Fregly2012 TKA 78 trials, Li2021 stroke 65 trials): the `caption_*` phrases never mention the pathology, and the Li2021_S05 fits have about 1.8 times the healthy fit error (standing 26.6 mm vs 14.7 mm) (T2M audit R21). Use them as an out-of-distribution stratum (`eval_stratum`).
+- Trials above 100 Hz (Han2023 and some Carter2023 at 250 Hz, Tiziana2019 at 201 Hz) ship on their native grid. Resampling them to 100 Hz without a low-pass filter (as the T2M encoders do) aliases force-plate noise (Han2023: 7-30 N RMS below 50 Hz; peaks are kept) (T2M audit R22).
+- vanderZee2022 walking: the median peak hip flexion torque is 1.95 N m/kg, against 1.0 (Carter2023) and 1.36 (Moore2015); the cause is not identified (possibly the plate cross-talk above) (T2M audit R23).
+- `q_kin` beyond 2 pi on a shoulder DOF in a few trials (`qc_q_kin_wrap`, T2M audit R12): an AddB Euler branch of the pass-0 target, not unwrapped; the arm frames are masked in `arm_event_ok_kin` (1.2.1). The mask covers only the frames beyond 2 pi (+-0.1 s); in some of these trials the wrapped stretch is wider (an arm DOF of `q_kin` more than pi/2 from `q_gt` outside the mask), so skip arm losses on the whole trial if in doubt.
+- Constant-labelled treadmill belts that change speed (`qc_belt_speed_change`, `_suspected`; T2M audit R16) and segments whose label does not match the motion (`label_conflict_codes` SEGMENT_MOTION_MISMATCH; R17) are flagged in 1.2.1; trials and labels are unchanged.
+
+## License and attribution
+
+The ForceBody data are released under the Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0). Commercial use is not permitted.
+
+- Fields derived from AddBiomechanics (forces, AddB kinematics, torques, uncertainty, metadata) build on the AddBiomechanics dataset (CC BY 4.0). Cite AddBiomechanics and every source study you use.
+- SKEL-derived fields (`poses*`, `trans*`, `joints*`, `betas`, `skel_gender`) are also subject to the SKEL model license, which allows non-commercial scientific research only. Building meshes from these fields requires the SKEL model, which you obtain from its authors under their license.
+- The code in this release (`forcebody_io.py`, `visualize.py`, `benchmark/`) and in the GitHub repository is released under the MIT license.
+
+## How to cite
+
+```bibtex
+@inproceedings{forcebody,
+  title = {ForceBody},
+  note = {citation to be completed at publication}
+}
+@inproceedings{werling2024addbiomechanics,
+  title = {AddBiomechanics Dataset: Capturing the Physics of Human Motion at Scale},
+  booktitle = {ECCV},
+  year = {2024},
+  doi = {10.1007/978-3-031-73223-2_27}
+}
+@article{werling2023addbiomechanics,
+  title = {AddBiomechanics: Automating model scaling, inverse kinematics, and inverse dynamics from human motion data through sequential optimization},
+  journal = {PLOS ONE},
+  year = {2023},
+  doi = {10.1371/journal.pone.0295152}
+}
+```
+
+## Versions
+
+| version | date | note |
+|---|---|---|
+| 1.0.0-reviewed | 2026-05-07 | reviewed build (paper numbers) |
+| internal v1 | 2026-08-31 | internal build |
+| internal 1.1 | 2026-09-27 | internal build (frame and timebase fixes) |
+| 1.2.0 | 2026-10-11 | first frozen 1.2 build (first build 2026-10-09); superseded by 1.2.1 (QC mask erratum) |
+| 1.2.1 | 2026-10-12 | 1.2.0 with corrected QC masks and flags (pose, force and torque arrays unchanged) |
+| 1.3.0 | 2026-10-29 | this release: Hamner2013 study id (40 trial keys renamed, map shipped), `sex_resolved` corrected, benchmark results, documentation; arrays otherwise identical to 1.2.1, see CHANGELOG.md |
+
+## Maintenance
+
+Issues and corrections are tracked per version in CHANGELOG.md; replaced arrays are kept in an internal v1.1 provenance archive (not uploaded), so every change can be traced back to v1.1.
+

MD5SUMS.txt

@@ -1,5 +1,5 @@
 fe0153904dd9cf3ec5c174dc0c91919b  ./CHANGELOG.md
-e089842c67ee7f3784922d55561939d3  ./README.md
+29b1ac48ac11a03e445ffd7dababea85  ./README.md
 1989b413f574403d1aa72b52bdf394af  ./SCHEMA_v1.3.csv
 16725af040dd20ce2d7522a34aa8e5dc  ./gait_events.csv
 557efe2ff4a7c31d52e3eed707a59253  ./manifest.csv
@@ -11155,3 +11155,4 @@ f41b5d9a18a82419c1eb029911b82f7f  ./trials/vanderZee2022/S10/vanderZee2022_S10_w
 e2b12456ebf056da7cd9f5a451ac2afc  ./trials/vanderZee2022/S10/vanderZee2022_S10_walk_112.npz
 989be65c15591198dc4242e90046b8f5  ./trials/vanderZee2022/S10/vanderZee2022_S10_walk_113.npz
 288f681179e42c09619d77e007bb7530  ./uid_map_v12_to_v13.csv
+8bf3b934ca02812b4596b2b38ff1356d  ./DETAILS.md

README.md

@@ -25,366 +25,78 @@ configs:
 
 # ForceBody
 
-Release 1.3.0, frozen 2026-10-29 (file checksums in MD5SUMS.txt). Trial file format v1.2 (`release_version` in each trial file).
+**Force-Paired Parametric Body Motion with Torque Uncertainty** (NeurIPS 2026, Evaluations & Datasets Track)
 
-ForceBody pairs the SKEL body model with measured ground reaction forces (GRF), inverse-dynamics joint torques and Monte Carlo torque uncertainty for 10,386 motion trials (9,689,808 frames, 26.89 h; duration = `num_frames` / `fps`) of 140 persons (75 male, 55 female, 10 sex not reported) from 10 studies (AddBiomechanics). Every trial is one NumPy `.npz` file; no nimblephysics, OpenSim or AddBiomechanics tooling is needed to read it.
+## 👉 Code, loader and benchmark: [github.com/DominoAI-Lab/ForceBody-NeurIPS-ED-2026](https://github.com/DominoAI-Lab/ForceBody-NeurIPS-ED-2026)
 
-Since version 1.2, ForceBody ships two SKEL pose sets per trial (one fitted to the kinematics-only AddBiomechanics pass, one to the force-aware dynamics pass), cleaned GRF, recomputed torques and uncertainty for every trial, one body shape per person, corrected metadata, frame-level quality masks, and fixed splits. Read "Choosing a pose source" and "Leakage policy" before training anything that predicts or scores forces.
+This page holds the data only. Release 1.3.0 (2026-10-29).
 
-| study | persons | trials |
-|---|---|---|
-| Carter2023 | 50 | 7,006 |
-| Falisse2017 | 11 | 70 |
-| Fregly2012 | 4 | 78 |
-| Hamner2013 | 10 | 40 |
-| Han2023 | 7 | 240 |
-| Li2021 | 1 | 65 |
-| Moore2015 | 12 | 1,019 |
-| Tiziana2019 | 25 | 619 |
-| Uhlrich2023 | 10 | 160 |
-| vanderZee2022 | 10 | 1,089 |
-| total | 140 | 10,386 |
+<p align="center"><img src="assets/running_hamner2013.gif" width="100%"></p>
 
-Study ids follow the first author and year of the source study (`study_citation` gives the citation key; Tiziana2019 = Lencioni et al. 2019). Release 1.3.0 renamed Hammer2013 to Hamner2013 (Hamner and Delp 2013): the 40 trial keys, folders and person ids changed (`uid_map_v12_to_v13.csv`, manifest column `trial_uid_v12`). Fields that point into the AddBiomechanics source (`b3d_path`, `subject_id_raw`, `trial_uid_v1`, the `models/` file names) keep the AddBiomechanics folder spelling Hammer2013.
+SKEL body motion paired with measured ground reaction forces (GRF), inverse-dynamics joint torques and a per-frame, per-joint torque uncertainty σ<sub>τ</sub>.
 
-## Layout
+| Trials | Subjects | Hours | Frames | Sources |
+|:---:|:---:|:---:|:---:|:---:|
+| 10,386 | 140 | 27 | 9.7M | 10 studies (AddBiomechanics) |
 
-This Hugging Face repository holds the data only. The loader (`forcebody_io.py`), the renderer (`visualize.py`, `VISUALIZATION.md`), the benchmark card, cache builder and scorer (`benchmark/`) and the baseline code are in the GitHub repository https://github.com/DominoAI-Lab/ForceBody-NeurIPS-ED-2026. The v1.1 provenance files and the Monte Carlo torque percentiles are not part of this upload.
+## Demos
 
-```
-ForceBody_release_v1.3/
-  trials/<study>/S<NN>/<trial_uid>.npz        core arrays, 547 fields (SCHEMA_v1.3.csv)
-  manifest.csv, manifest_train.csv, manifest_test.csv   one row per trial (every scalar field + metadata)
-  uid_map_v12_to_v13.csv                     the 40 trial keys and paths renamed in 1.3.0 (Hammer2013 -> Hamner2013)
-  name_map.csv, name_map.json                trial_uid -> AddBiomechanics source file and trial (`split` = the AddBiomechanics source split, not split_addb)
-  persons.csv                                one row per person: betas, sex, height, masses, SHAPY measures, splits
-  subjects.csv                               per-person metadata table (v1.1 layout, v1.2 values)
-  gait_events.csv                            GRF heel strikes and toe-offs (walking / running)
-  models/                                    AddB pass-0 and pass-2 scaled OpenSim models per b3d file (.osim.gz),
-                                              body_segments.csv (segment masses, local COM)
-  marker_vertex_map.json                     marker name -> SKEL skin vertex used by the fit
-  SCHEMA_v1.3.csv                            field, dtype, shape, unit, frame, version_added, description
-  README.md, CHANGELOG.md
-```
+| Walking | Sit-to-stand |
+|:---:|:---:|
+| <img src="assets/walking_uhlrich2023.gif" width="100%"> | <img src="assets/sit_to_stand_uhlrich2023.gif" width="100%"> |
+| **Drop jump** | **Stair ascent** |
+| <img src="assets/drop_jump.gif" width="100%"> | <img src="assets/stair_ascent_falisse2017.gif" width="100%"> |
 
-## Choosing a pose source
+Torque |τ| (left body) and uncertainty σ<sub>τ</sub> (right body) on six activities.
 
-Each trial has two SKEL fits. Both have every field and every QC mask; pick one with `pose_source`.
+<p align="center"><img src="assets/activities_grid_tau_sigma.gif" width="100%"></p>
 
-| `pose_source` | fields | fitted to | default use |
-|---|---|---|---|
-| `pass0` (alias `kin`) | `poses`, `trans`, `joints`, `q_kin`, `qd_kin`, `qdd_kin`, `addb_joints_kin` | AddB kinematics pass (pass 0) + 30 Hz 2nd-order Butterworth filter (= AddB pass 1); never saw the force plates | force and torque estimation, physics critics p(tau \| motion), any metric that scores forces from motion |
-| `pass2` (alias `dyn`) | `poses_dyn`, `trans_dyn`, `joints_dyn`, `q_gt`, `qd_gt`, `qdd_gt`, `addb_joints_dyn` | AddB dynamics pass (pass 2); consistent with the GRF and torque labels | text-to-motion (motion only, or motion + GRF + torque), T2M evaluators |
+## Files
 
-```python
-import forcebody_io as fio
-d = fio.load_trial("trials/Moore2015/S10/Moore2015_S10_walk_014.npz", pose_source="pass0")
-# common keys: poses, trans, joints, q, qd, qdd, addb_joints, pose_usable, pose_source
-# plus every GRF / torque / mask / metadata field of the file
+```
+trials/<study>/S<NN>/<trial_uid>.npz   one file per trial (all arrays below)
+models/                                AddBiomechanics OpenSim models per subject (used for the torques)
+manifest.csv  (+ _train, _test)        one row per trial: metadata, split, quality flags
+persons.csv, subjects.csv              one row per subject: SKEL shape, sex, height, mass
+SCHEMA_v1.3.csv                        name, shape, unit and frame of every field
+DETAILS.md                             full documentation (masks, conventions, known issues)
 ```
 
-`pose_source` is required (`ValueError` otherwise). `pose_usable` is always True for `pass0` and equals `poses_dyn_usable` for `pass2` (False in 15 trials: force/motion-capture desync). What pass 2 changes (AddB documentation and our audit): AddB moves the pelvis so the centre-of-mass path matches the measured GRF, then refits poses and body scales. COM-GRF Newton consistency improves (r 0.9947 -> 0.9998), but stance-foot sliding rises (0.064 -> 0.079 m/s) and the p90 marker error rises (26.8 -> 36.0 mm). Joint centres differ by a median 9.6 mm, mostly a constant bone-rescaling offset. Pass 2 also changes the motion on the 11.7% of frames without GRF.
-
-Re-timed trials (27; `skel_fit_target_dyn == "kin_retimed"`): the force stream was shifted in time to match the motion capture (`grf_retimed_ms`). Their pass-2 fit had been bent to the misaligned force, so `poses_dyn`, `trans_dyn`, `joints_dyn` and `addb_joints_dyn` equal the pass-0 fields, `q_gt`, `qd_gt`, `qdd_gt` and `tau_gt_det` are not usable (`q_gt_usable`, `tau_gt_det_usable` False), and `tau_selfconsistent`, `mu_tau` and `sigma_tau` are computed on `q_kin` with the pass-2 skeleton (`tau_sc_kinematics`, `mc_kinematics`). `load_trial(..., "pass2")` returns `q_kin` as `q` for these trials (`q_source`).
-
-## SKEL fit versions and fix rounds
-
-Both pose sets come from one refit code base that went through several fix rounds before this release. `skel_fit_code_version` / `skel_fit_code_version_dyn` and `skel_fit_source_run` / `skel_fit_source_run_dyn` record per trial which code produced each fit.
-
-| fit | code version | trials |
-|---|---|---|
-| `poses` | v1.2-fixround-2026-10-03c | 10,291 |
-| `poses` | v1.2-fixround-2026-10-04d | 95 |
-| `poses_dyn` | v1.2-fixround-2026-10-03c | 8,940 |
-| `poses_dyn` | v1.2-fixround-2026-10-07e | 9 |
-| `poses_dyn` | v1.2-fixround-2026-10-08i | 815 |
-| `poses_dyn` | v1.2-fixround-2026-10-09l | 622 |
-
-What the rounds changed (all trials unless a count is given):
-
-- scapula: the right scapula elevation bound of SKEL `kin_skel.py` has the wrong sign; it is replaced by the mirror of the left bound ([0.1, 0.4] rad). The bound sizes (0.1, 0.4 rad) have no published source (SKEL issue #19) and elevation sits on them in many fits (see Known issues).
-- marker handling: aliases for trunk / shoulder markers (Han2023, Uhlrich2023) and acromion vertices moved to the acromion tip (`marker_vertex_map.json`).
-- kinematics target (`q_kin`): where the AddB pass-0 left arm parks on its joint limit or hops (> 30 deg per frame) and where the elbow parks at 0, the arm is re-solved by inverse kinematics to the markers before the 30 Hz filter; a window is kept only if the marker error does not rise (hop windows: by at most 1 mm). 875 trials (`q_kin_source == "addb_pass0_armfix_lp30"`). Inside full-body hop windows the leg and trunk target also changes.
-- fit: a continuity guard repairs fit-only branch flips of arm, leg and root DOF groups; Stage-2 joint weights of femur and tibia raised from 5 / 3 to 10 (our choice) so the knee follows the target; an extra lower-body stage (2f) is kept when it passes the whole-body error gate. Trade-off: the pelvis joint error rises (median about 2 mm) because the SKEL femur is shorter than the AddB femur.
-- head: the head is pinned during the main fit and fitted afterwards to the head markers (orientation only, neck limits of bsm.osim). 1,948 trials have `head_postfit`; the others (`qc_head_untracked`) keep head DOFs 23-25 at 0, so the head follows the thorax.
-
-### Dynamics-pass target repair (`poses_dyn` is not pure pass 2 everywhere)
-
-`poses_dyn` is fitted to the AddB dynamics pass (`q_gt`) except where that target was repaired. `skel_fit_target_dyn` names the target, `dyn_target_source [T,37]` marks per frame and AddB DOF which values replaced `q_gt` (0 = pure pass 2), `dyn_target_modified_frac` is the fraction of modified frames, and `addb_joints_dyn` are the joint centres of the target actually fitted. `q_gt` itself is unchanged, so in the flagged frames `poses_dyn` and `q_gt` disagree.
-
-| `skel_fit_target_dyn` | trials | target |
-|---|---|---|
-| `addb_pass2` | 8,939 | pure pass 2 (`q_gt`) |
-| `addb_pass2_armsplice` | 9 | pass 2 with the kinematics-target (re-solved) arm spliced in inside the accepted arm windows, cosine ramps |
-| `addb_pass2_repaired_v3a` | 791 | pass 2 with the kinematics target (whole body, aligned at the window edges) in frames without valid GRF, the kinematics root on GRF-valid frames where the pass-2 pelvis deviates by more than 50 mm, kinematics values on pass-0 IK outlier frames, left-arm splice; 0.25 s cosine ramps |
-| `addb_pass2_repaired_v4s` | 620 | v3a plus a position-based left-arm IK on the pass-2 skeleton and the AddB acceleration-minimizing filter on all 37 DOFs (removes 6-30 Hz wobble of pass 2) |
-| `kin_retimed` | 27 | `poses_dyn` = `poses` (re-timed trials, below) |
-
-Bits of `dyn_target_source`: 1 kinematics value (GRF-invalid window or pass-2 root deviation), 2 left-arm splice, 4 pass-0 IK outlier repair, 8 left-arm position IK, 16 acceleration-minimizing filter, 32 other difference from `q_gt` (arm splice). 1,392 trials have a modified frame (median modified fraction 0.83); 1,048,169 of 9,689,808 frames. `dyn_arm_spliced [T,2]` marks frames whose dyn-target arm comes from the kinematics or IK arm (622 trials, `qc_dyn_arm_spliced`). The repair trades Newton consistency for a plausible root and arms where pass 2 had no force support: on the repaired trials the root path follows the kinematics target in GRF-invalid windows, so GRF-free frames of `poses_dyn` are no longer force-aware there. For a force-aware motion source with the arm and root fixes, use `poses_dyn` with its masks; for pure AddB pass-2 kinematics use `q_gt`.
-
-## Leakage policy
-
-AddBiomechanics warns: "If you use the output of the dynamics pass, you will be training your model on data that has already been fine tuned to match the force plate data, and your model will overfit to the clues that the optimizer inserts into the motion", and for GRF prediction to "use as input features only the kinematics pass" (nimblephysics documentation, working with AddBiomechanics data). GaitDynamics uses the kinematics pass "to prevent the leakage of force data ... into the kinematics"; InferBiomechanics (AddB benchmark code) takes inputs from the kinematics pass and labels from the last pass.
-
-How large the effect is here: recovering the total GRF from the centre-of-mass acceleration alone, with no learning, has a median error of 2.56 N/kg on pass-1 kinematics and 0.2 N/kg on pass-2 kinematics.
-
-Rule (an allowlist): a model that predicts or scores forces or torques may take as input only the pass-0 pose set (`poses`, `trans`, `joints`, `q_kin`, `qd_kin`, `qdd_kin`, `addb_joints_kin`, or `load_trial(..., "pass0")`), `betas`, `skel_gender`, `mass_kg`, `height_m`, `sex`, `age` and person-free text metadata (`forcebody_io.ALLOWED_INPUT_FIELDS`). Every other field is excluded, in particular the dynamics-pass pose set (`poses_dyn`, `trans_dyn`, `joints_dyn`, `addb_joints_dyn`, `q_gt`, `qd_gt`, `qdd_gt`), the labels (`tau_*`, `mu_tau`, `sigma_tau`, `percentiles`, `grf*`, `cop*`, `contact_*`, `grf_valid_mask`) and the fields derived from the GRF: `mass_kg_grf`, `mass_dyn_scale`, `mass_kg_dynamics*`, `cadence_spm_grf`, `stride_time_s_med`, `duty_factor_*`, `gait_events.csv`, `support_side`, `support_side_grf_share`, `caption_support_side`, `floor_height_m`, `speed_belt_grf_mps`, `mc_frame_ok`, `eval_*`, `s8b_*`, the usability flags, the `qc_*` fields and every `*_dyn` / `dyn_*` field (`dyn_target_source` is placed by the GRF-valid windows). `forcebody_io.LEAKY_INPUT_FIELDS` lists these as a safety net; the benchmark loader refuses them and any input that is not a benchmark input. Results computed with `pass2` inputs must be labelled leaky and are not comparable with the official benchmark numbers. The body shape (`betas`) was fitted to pass-0 bone lengths, the recorded height and a person mass target; for Moore2015 that target is the GRF calibration-pose mass (a static, person-level weight).
-
-## Force benchmark
-
-The force benchmark (joint torques T-tau and per-foot GRF T-GRF from motion) is defined in [benchmark/BENCHMARK.md](benchmark/BENCHMARK.md) with the machine-readable `benchmark/spec_v12.json`, a cache builder (`benchmark/build_bench_cache_v12.py`) and the reference scorer (`benchmark/score_v12.py`). The scripts import `forcebody_io.py` from the release root. BENCHMARK.md lists the split sizes and the baselines retrained on 1.2.1 (5 torque models and the GRF MLP; 3 torque models pending). The benchmark data of 1.3.0 are identical to 1.2.1 except the 40 renamed Hamner2013 keys.
-
-## Conventions
-
-| item | convention |
-|---|---|
-| frames | `addb_lab`: raw AddB lab frame, y up (grf, cop, contact_torque, markers, q_*, tau_*). `skel_world`: `flip_xz(addb_lab)` (x -> -x, z -> -z, y unchanged): poses, trans, joints, addb_joints_*, *_aligned, cop_aligned_foot. Every `*_aligned` field is exactly `flip_xz` of its raw field (max difference 0) |
-| gravity | -y in every study |
-| contacts | index 0 = right foot (calcn_r), 1 = left foot (calcn_l), 2 = pelvis (Falisse2017 chair) |
-| trans | SKEL root translation (`trans_frame == "skel_world"`). The pelvis joint is `trans + j0(betas)`, not `trans`; j0 is about (0.0095, -0.236, 0.103) m for a male rest pose, so rotating `trans` alone misplaces the body by 0.12-0.16 m |
-| joints | `joints[T,24,3]` in `joint_names` order (SKEL / OpenSim: 0 pelvis, 1 femur_r, ...) |
-| DOF names | `skel_pose_names` (46 SKEL pose DOFs; `skel_dof_valid` False = pinned to 0 in the fit), `dof_names_opensim` (37 AddB DOFs, OpenSim Rajagopal coordinate names and sign conventions) |
-| time | `t_i = i / fps_true_grid`. `fps` is the nominal rate; the true grid differs slightly (61 Hz: 64, 99 Hz: 470, 100 Hz: 9,640, 101 Hz: 76, 201 Hz: 111, 250 Hz: 25 trials by rounded rate) |
-| heading | use `heading_canonical_deg` (SKEL frame) only |
-| mirroring | swapping left/right SKEL DOFs with a sign table is not an exact mirror (MPJPE 32 mm, feet 45-77 mm); mirror the mesh or the joint positions instead |
-
-## Body mass fields
-
-| field | meaning | use |
-|---|---|---|
-| `mass_kg` | recorded mass (unchanged from v1.1) | model and critic inputs |
-| `mass_kg_dynamics` | AddB pass-2 skeleton mass times `mass_dyn_scale` (already applied) | the only mass for normalizing GRF, torque and sigma labels (N/kg, N m/kg, BW) |
-| `mass_kg_dynamics_v11`, `mass_dyn_scale` | v1.1 dynamics mass and the approved per-file rescale | provenance. Never multiply `mass_kg_dynamics` by `mass_dyn_scale` again. `mass_kg_dynamics_v11` stays in the core file (the only `_v11` value there besides the QC count `qc_grf_endpoint_valid_v11`) |
-| `mass_kg_grf` | per-trial GRF-implied mass estimate | diagnostic |
-| `caption_mass_kg`, `shape_mass_target_kg`, `mass_source` | person mass for captions and for the shape fit (recorded; Moore2015 = GRF calibration pose) | text, shape |
-
-`mass_dyn_scale` differs from 1 in 491 trials (14 b3d files), where the AddB link masses were inconsistent with the measured GRF.
-
-## Quality masks
-
-Nothing is deleted; problems are flagged. Frame masks (`[T]` or `[T,2]`): `grf_frame_ok` (GRF validity: GRF losses and statistics), `grf_frame_strict_ok` (whole frame without zero-force or misassigned feet), `grf_foot_ok` (per foot, columns right, left; 1.2.1), `tau_frame_ok` (torque losses), `mc_frame_ok` (use of sigma_tau), `kin_frame_ok` (pelvis not flipped), `cop_frame_ok` (per foot), `grf_contact_state` (per foot: 1 = in contact on a `grf_frame_ok` frame, 0 = not in contact on a `grf_frame_ok` frame, -1 = unknown: no measured force, or a measured frame outside `grf_frame_ok`), `eval_tau_frame_ok` (= `tau_frame_ok` and `kin_frame_ok`), `eval_grf_frame_ok` (= `grf_frame_ok` and `kin_frame_ok`).
-
-GRF validity and CoP trust (1.2.1). `grf_frame_ok` is GRF validity only: `grf_valid_mask`, not an endpoint or a blanked tail, and a consistent force label on every used contact (`grf_contact_ok`). A loaded contact with `contact_status` 3 (force valid, CoP projected on the foot and not trusted) counts as valid. CoP trust gates only `cop_frame_ok` (trusted CoP status 1, 2 or 9 on that foot) and `tau_frame_ok` (no used contact with status 3, because the torque depends on the CoP). In 1.2.0 the status-3 frames were not in `grf_frame_ok`, so on fixed-point-CoP trials (`qc_cop_fixed_point`, Carter2023) the GRF masks kept only unloaded frames (CHANGELOG, erratum); in 1.2.1 170,158 status-3 frames of 1,158 trials are in `grf_frame_ok`. The QC scalars are still computed on `grf_frame_ok` without the status-3 frames, as in 1.2.0, so their values did not change, except the mask summaries (`grf_frame_ok_frac`, `grf_frame_strict_ok_frac`, `qc_grf_contact_bad_frames`) and the evaluation flags.
-
-Per-foot GRF mask (1.2.1). `grf_frame_strict_ok` drops the whole frame when either foot is zero-force grounded, force-in-air, unmeasured in stance or has its CoP off the foot. `grf_foot_ok` drops only the zero-force-grounded foot itself; the other three flags point to a likely plate misassignment (the force of the other foot may be on the wrong plate), so they still drop both feet of the frame (`grf_foot_ok.all(1)` equals `grf_frame_strict_ok`). It keeps 854,888 loaded foot-frames (vertical GRF > 20 N) that the strict mask removes.
-
-Masked values are not NaN: outside a mask the arrays keep their raw values. `cop` and `contact_torque` are 0 where the force is 0, the GRF of the AddB endpoint frames is 0, and `grf` / `grf_aligned` can be non-zero on frames outside `grf_valid_mask` (force readings that AddB marked as missing). A 0 is not a measurement; always apply the mask.
-
-Trial flags:
-
-| flag | trials True |
-|---|---|
-| `force_label_usable` | 10,372 |
-| `torque_label_usable` | 10,067 |
-| `eval_motion_trial_ok` | 9,697 |
-| `eval_grf_trial_ok` | 9,769 |
-| `eval_torque_trial_ok` | 8,256 |
-| `qc_pass2_equals_pass1` | 1,249 |
-| `qc_skel_grf_newton_mismatch` | 244 |
-| `qc_grf_single_channel` | 37 |
-| `qc_mass_dyn_vs_grf_flag` | 20 |
-| `qc_overlap_pair_drop` | 8 |
-| `qc_overlap_motion_drop` | 200 |
-
-Evaluation flags. `eval_grf_trial_ok` and `eval_torque_trial_ok` require usable force labels and exclude single-channel force plates (`qc_grf_single_channel`: one plate carries both feet, so per-foot GRF and the foot assignment of the torques are wrong; also excluded from `torque_label_usable`), byte-identical duplicates (`qc_duplicate_drop`), the Han2023 trimmed copies of a re-exported capture (`qc_overlap_pair_drop` = `eval_exclude_duplicate` and not `qc_duplicate_drop`), static calibration, transition and pause segments, and trials whose dynamics mass disagrees with the GRF-implied mass by more than 5% (`qc_mass_dyn_vs_grf_flag`); `eval_torque_trial_ok` also requires a root residual force of at most 0.1 BW. Since 1.2.1 both also require at least one loaded evaluation frame (`qc_grf_loaded_eval_frames` > 0: a foot vertical GRF above 20 N on an `eval_grf_frame_ok` frame; for torques also `qc_tau_loaded_eval_frames` > 0); 83 trials with usable force labels have none (most have `grf_valid_mask` False on every frame). `eval_motion_trial_ok` applies the same duplicate / segment exclusions and in addition drops one member of each overlapping Tiziana2019 capture pair (`qc_overlap_motion_drop`: the member with fewer GRF-valid frames). The Tiziana2019 pairs share no GRF-valid frame, so both members stay in force evaluation. Always combine a trial flag with its frame mask.
-
-`force_label_usable` is False where force and motion capture are out of sync and could not be re-timed (14 trials); every force, torque, MC, contact and CoP frame mask is then False. `qc_skel_grf_newton_mismatch` marks trials whose SKEL root path does not follow the GRF without any time-lag evidence; their force labels are kept. Pathological persons are never excluded; `eval_stratum` reports them separately. Every QC field is described in SCHEMA_v1.2.csv.
-
-Falisse2017 chair channel (contact index 2, `contact_bodies` = `pelvis`). `chair_contact` [T] marks the frames where the subject sits on the instrumented chair (the `grf_contact_label` hysteresis on the chair vertical force, not restricted to `grf_frame_ok`; most seated frames are outside `grf_valid_mask`), `qc_chair_channel_active` marks trials with any such frame, and `qc_extra_channel_zero` marks trials whose chair channel carries no force at all (walk, stairs). On those trials `grf_contact_ok[:, 2]` is False on every frame and `grf_frame_ok` ignores the channel. The trial-level manifest column `chair_contact` (protocol metadata) is a different field from the per-frame npz array of the same name.
-
-### Pose masks of the fix rounds
-
-These masks describe the SKEL pose sets (True = usable). Each exists for both pose sets (`_kin` = `poses`, `_dyn` = `poses_dyn`); AND them into the loss mask of the listed DOFs. Masks are dilated by 0.1 s (our choice).
-
-| field | shape | False on | trials with a False frame | frames |
-|---|---|---|---|---|
-| `arm_event_ok_kin` | [T,2] (left, right) | arm discontinuities (arm-jump diagnosis of 2026-10-07 and a re-scan of the final fits); arm DOFs | 272 | 231,278 |
-| `arm_event_ok_dyn` | [T,2] | same for `poses_dyn` | 316 | 217,726 |
-| `trunk_event_ok_kin` | [T] | AddB pass-0 trunk shake (class A3); lumbar / thorax DOFs 17-22 | 143 | 200,423 |
-| `trunk_event_ok_dyn` | [T] | same for `poses_dyn` | 155 | 200,116 |
-| `dyn_root_jump_ok` | [T] | pass-2-only whole-body jumps (class A6): drop the whole `poses_dyn` frame | 108 | 2,858 |
-| `fit_event_ok_kin` | [T,7] | temporal events of the final fit per joint group (`fit_event_groups`: pelvis, leg_r, leg_l, spine, head, arm_r, arm_l): fit-only spikes, spikes inherited from the target, one-frame DOF steps, and Euler branch flips (one-frame step > pi) | 1,820 | 251,010 |
-| `fit_event_ok_dyn` | [T,7] | same for `poses_dyn`, measured against its own (repaired) target | 1,808 | 254,087 |
-| `kin_hop_edge_frame_ok_r` | [T] | right-arm frames at a hop-window edge of the arm re-solve where two Euler branches are joined (`qc_kin_hop_edge_branch_blend`) | 3 | 75 |
-
-Also per trial: `addb_limit_mask_kin` / `addb_limit_mask_dyn` [T,11] (the fit target sits on an AddB joint limit; the dyn mask is the union of the pass-2 and pass-0 on-limit frames, `addb_limit_mask_names`), `qc_arm_event_classes_kin` / `_dyn` (diagnosis classes present), and the trial flags below. Where `qc_upper_body_unobserved` is True (no torso / arm marker at all, e.g. vanderZee2022 S09) the arm, trunk and head masks are False on every frame of both pose sets: the SKEL arms, trunk and head are unconstrained there.
-
-| trial flag | trials True | meaning |
-|---|---|---|
-| `qc_upper_body_unobserved` | 133 | no upper-body marker; arms / trunk / head masked |
-| `qc_head_untracked` | 8,438 | fewer than 2 head markers; head DOFs 23-25 are 0 |
-| `qc_kin_armfix_edge` | 20 | arm re-solve window-edge artefact of the kinematics target (frames in `arm_event_ok_kin`) |
-| `qc_kin_hop_edge_branch_blend` | 3 | hop-window edge joins two right-arm Euler branches |
-| `qc_upper6_rise10_kin` | 13 | upper-body joint error of `poses` rose by > 10 mm in the fix rounds (our threshold); arm-marker error is better in almost all; flag, not exclusion |
-| `qc_upper6_rise10_dyn` | 18 | same for `poses_dyn` |
-| `qc_heading_rms3_kin` | 3 | pelvis heading lost > 0.1 correlation and detrended heading RMS > 3 deg (our thresholds) |
-| `qc_heading_rms3_dyn` | 2 | same for `poses_dyn` |
-| `qc_dyn_arm_spliced` | 622 | `poses_dyn` arms follow the kinematics / IK arm in `dyn_arm_spliced` frames |
-| `qc_tau_sc_q_kin_pre_armfix` | 0 | re-timed trial whose torque labels were computed on `q_kin` before the arm re-solve (`mc_kinematics == "q_kin_pre_armfix"`) |
-| `qc_pose_wrap_n_kin` > 0 | 1 | Euler branch flip in `poses` (masked, not unwrapped) |
-| `qc_pose_wrap_n_dyn` > 0 | 1 | same in `poses_dyn` |
-| `qc_head_at_limit_frac_*` > 0.05 | 11 | head post-fit at a neck limit on > 5% of frames; do not use the head orientation there |
-
-Added in 1.2.1 (T2M audit; flags and masks only, no pose refit):
-
-| field | trials | meaning |
-|---|---|---|
-| `qc_q_kin_wrap` | 68 | `q_kin` (fit target of `poses`) beyond 2 pi on a shoulder DOF (an AddB Euler branch; `qc_q_kin_abs_gt_2pi_dofs`); the frames of that arm are False in `arm_event_ok_kin`, and in `arm_event_ok_dyn` on kin_retimed trials. Not unwrapped |
-| `knee_clamp_frame_kin` / `_dyn` [T,2] (right, left), `qc_knee_clamp_frac_*` | 4,870 (kin, any frame); 1,061 kin / 1,294 dyn above 10% of frames | SKEL knee on its 0 bound while the AddB target knee is flexed 3 deg or more (our threshold). Flag only; `forcebody_io.load_trial` returns the mask of the chosen set as `knee_clamp_frame` |
-| `qc_belt_speed_change` / `qc_belt_speed_change_suspected` | 4 / 8 | treadmill belt labelled constant whose speed changes in the trial (both pose sets / one pose set) |
-| `label_conflict_codes` contains SEGMENT_MOTION_MISMATCH | 28 | segment label and motion disagree (Carter2023 static-trial stand segments with a leg lift, Han2023 pause / sit / short action segments); labels and captions not changed |
-
-## Uncertainty
-
-`mu_tau` and `sigma_tau` ship in the core file for all 10,386 trials, the torque `percentiles` (with `percentile_values`) are kept in the internal v1.1 provenance archive and are not part of this upload; `has_uncertainty` is True for 10,382 (False: the trial is shorter than one period of the 6 Hz noise band, sigma is 0). `has_uncertainty_v11` (manifest) marks the 8,652 trials that had MC in the paper version. sigma_tau is the kinematic sensitivity of the torque to 1.6 deg band-limited joint-angle noise on `q_gt` (pass 2; `q_kin` on re-timed trials) with the measured GRF held fixed. It is not the uncertainty of `poses`, and not a label-reliability score. Normalize it by `mass_kg_dynamics` only, and use it only where `mc_frame_ok` and `torque_label_usable` hold. Per-trial ratios to the paper-version sigma have p5-p95 0.85-1.20. The sigma statistics of the paper use the trials with `has_uncertainty` and `grf_valid_frac` >= 0.5 (8,732 trials).
-
-## Time alignment
-
-| item | status |
-|---|---|
-| release grid | one grid per trial for kinematics, forces and MC (`fps_true_grid`) |
-| AddB endpoints | frames 0 and T-1 carry no GRF; they are never in `grf_frame_ok` |
-| duration | `duration_s` = `num_frames` / `fps` (nominal rate, v1 convention); the time span of the grid is (`num_frames` - 1) / `fps_true_grid`, about one frame shorter |
-| force/mocap re-timing | 27 trials re-timed and validated against independent marker-based gait events; applied shift median 277 ms (range -85 to 320 ms) |
-| partial invalidation | 1 trial(s): force invalid from `force_invalid_from_frame` |
-| lag diagnostics | `qc_grf_kin_toeoff_lag_ms`, `qc_grf_kin_onset_lag_ms`, `qc_grf_newton_seg_lag_ms`, `qc_cop_foot_shift_ms` (positive = kinematics later than force) |
-
-## Floor and gait events
-
-- `floor_height_m`: median centre-of-pressure height (SKEL frame, y) over trusted firm-stance frames (`contact_status` 1, foot vertical force > 0.5 BW of `mass_kg_dynamics`, `grf_valid_mask`); NaN with fewer than 30 such frames. It comes from the force plates. On stairs and step activities it is the height of the loaded step surface, not of the floor.
-- No floor normal is shipped. A plane fitted to the SKEL sole height over the CoP positions tilts by 2-3 deg on level treadmills (heel-to-toe roll). The QC fields `floor_tilt_x_deg` / `floor_tilt_z_deg` (plane through the firm-stance CoPs) and `floor_tilt_x_kin_deg` / `floor_tilt_z_kin_deg` (SKEL sole height at the same samples) are diagnostics only; protocol inclines are in `incline_grade_pct` / `incline_label`.
-- `gait_events.csv`: heel strikes (`grf_contact_state` 0 -> 1) and toe-offs (1 -> 0) of each foot on walking and running trials with usable force labels; `frame` on the release grid, `time_s = frame / fps_true_grid`. `stride_time_s_med` is the median same-foot heel-strike interval (0.4-2.5 s, strides with an unknown (-1) frame inside are not used), `cadence_spm_grf` = 120 / `stride_time_s_med`, `duty_factor_r` / `duty_factor_l` the median stance fraction of a stride.
-- Consistency gate: where `cadence_spm_grf` differs from the kinematic `cadence_spm` (metadata) by more than 10% (our threshold), `qc_gait_event_inconsistent` is True, the four GRF gait scalars are NaN and the trial has no rows in gait_events.csv (28 trials).
-- Carter2023 running: in most trials `grf_valid_mask` also covers the flight frames (median `grf_valid_frac` 1.00); in some trials AddB marks the flight frames as missing GRF, and there GRF labels, T-GRF scores and `grf_contact_state` (-1) cover stance frames only and strides that contain such frames give no GRF gait scalars. On fixed-point-CoP trials (`qc_cop_fixed_point`) every loaded frame has `contact_status` 3; since 1.2.1 these frames are in `grf_frame_ok` and `grf_contact_state`, so these trials have GRF gait events, but they stay out of `cop_frame_ok` and `tau_frame_ok`. (1.2.0 stated the opposite: its GRF masks kept only the unloaded frames of these trials; CHANGELOG erratum.)
-
-## Metadata
-
-Every metadata column is in manifest.csv and the per-trial ones also in each trial file; SCHEMA_v1.3.csv gives the definition of each column. Groups: identity and capture structure (`person_id`, `subject_base`, `capture_id`, `segment_index`, `n_segments_in_capture`, `segment_role`, `qc_overlap_of`, `eval_exclude_duplicate`), activity (`activity_name`, `activity_recovered`, `activity`, `activity_sequence`, `activity_modifier`, `gait_style`, `source_task`, `setting`, `setting_motion`, `path`, `support_side`), protocol (`protocol_condition`, `condition_key`, `speed_*`, `incline_*`, `belt_*`, `cadence_*`, `step_*`), person (`sex`, `age`, `bmi`, `health_status`, `health_detail`, `footwear`) and captions (`caption_*`). The measured values (`speed_mps`, `cadence_spm`, `step_width_m`) come from forward kinematics of the AddB model; the running treadmill speed uses GRF stance frames, and `support_side_grf_share` and `speed_belt_grf_mps` use the GRF (Leakage policy).
-
-## Body shape
-
-`betas` are fitted once per person (identical in all trials of a person, persons.csv) to the pass-0 bone lengths, the recorded height and the person mass target, and `skel_gender` selects the SKEL model (`skel_gender_source`: height_rule 10, sex_label 130 persons). persons.csv reports SHAPY-style measurements of the shaped mesh (height = |y(HeadTop 411) - y(HeelLeft 3466)|, mass = volume x 985 kg/m^3, chest / waist / hip girths at vertices 6489 / 3501 / 1210). The girths are almost fully determined by height and mass (R^2 0.987-0.994); 41 (female) / 52 (male)% of the betas variance is bone proportion that height and mass do not explain. Claims about body shape should stay at the height / mass level.
-
-## Splits
-
-The Hugging Face configuration loads `manifest_train.csv` (split `train`, which holds the `split_addb_val` train and val persons; select val with `split_addb_val == "val"`) and `manifest_test.csv` (split `test`).
-
-`split_addb` (force benchmark train / test, person level) with `split_addb_val` (validation persons drawn from the train persons), and `split_t2m` (text-to-motion train / val / test / patho, person level). No person is in two folds of one split.
-
-All three are drawn with a stratified, seeded person-level search (2026-10-09): test and val persons cover the height x body-mass tertile cells of the healthy persons and the bottom / top 10% of height and mass, use different studies within a cell where possible, and cover as many activities as possible, while train keeps every activity, study and body-size cell that any other fold has. Test and val persons are drawn only from persons with at least 90% usable trials (split_addb test and val also need at least 90% trials with `eval_grf_trial_ok`). Pathological persons are `split_t2m=patho` and keep their earlier `split_addb` (separate `eval_stratum`). `split_addb` therefore no longer equals the split shipped with the AddBiomechanics source data. Splits of earlier versions are not compatible: caches or checkpoints trained on an earlier split may contain current test persons.
-
-| split_addb | persons | trials |
-|---|---|---|
-| test | 19 | 914 |
-| train | 121 | 9,472 |
-
-| split_addb_val | persons | trials |
-|---|---|---|
-| test | 19 | 914 |
-| train | 109 | 8,374 |
-| val | 12 | 1,098 |
-
-| split_t2m | persons |
-|---|---|
-| patho | 5 |
-| test | 35 |
-| train | 83 |
-| val | 17 |
-
-The split_t2m walking test set has 4 persons with a body mass target of 85 kg or more; the running test set has 0 (running is not evaluable at high body mass).
-
-## Health status and sensitive information
+Main arrays in each trial file (T = frames):
 
-| health_status | persons | trials |
+| Field | Shape | Content |
 |---|---|---|
-| TKA | 4 | 78 |
-| healthy | 135 | 10,243 |
-| stroke | 1 | 65 |
+| `poses`, `trans`, `betas` | `[T,46]`, `[T,3]`, `[10]` | SKEL pose, root translation, body shape |
+| `grf_aligned`, `cop_aligned_foot` | `[T,C,3]` | Measured GRF and centre of pressure per foot |
+| `tau_selfconsistent` | `[T,37]` | Inverse-dynamics joint torque |
+| `sigma_tau`, `mu_tau` | `[T,37]` | Monte Carlo torque uncertainty and mean |
+| `*_frame_ok` | `[T]` | Frame masks. Always apply them |
 
-The data include persons after total knee arthroplasty and after stroke (`health_status`, `health_detail`); this is health information. `trial_name` keeps the source names: 240 Han2023 names contain a capture date and the Fregly2012 names (trials: 78) contain subject initials. Ages range from 18 to 86 years (unknown in 200 trials). Do not attempt to re-identify persons.
+## Quick start
 
-## Intended and out-of-scope uses
-
-Intended: research on motion-to-force and force-aware motion models, text-to-motion with physical labels, biomechanics method development. Out of scope: clinical decisions or diagnosis, identifying or profiling persons, and human mesh recovery from images or video (there are no images or video in ForceBody).
-
-## Paper numbers
-
-The paper tables (Tables 3, 4, 5, 14 and 15) were computed on the reviewed build with the v1 labels and are not reproduced by v1.1, 1.2 or 1.3; benchmark baselines retrained on 1.2.1 are in benchmark/BENCHMARK.md. The Table 3 AddB row used dynamics-pass (pass 2) kinematics as input (see Leakage policy). The torque labels themselves moved between versions: scoring the v1.1 `tau_selfconsistent` against the paper labels gives RMSE / MAE / PCC 0.287 / 0.087 / 0.721, the same order as the model errors, so numbers from different versions must not be mixed in one table.
-
-## Known issues
+```bash
+hf download kwonjoon/ForceBody --repo-type dataset --local-dir ForceBody
+```
 
-- vanderZee2022: force-plate cross-talk remains after the plate re-zero (swing-foot readings depend on the other plate load); the root residual force is higher than in other studies.
-- Carter2023 downhill: AddB did not dynamics-process these kinematics; the root residual stays high and the torque labels are flagged. `grf_valid_mask_plate` is offered for GRF supervision.
-- Carter2023 trials whose raw plate CoP is unusable keep a fixed-point CoP (`qc_cop_fixed_point`, `qc_tau_cop_unreliable`); exclude them from CoP and torque evaluation. Their forces are valid: since 1.2.1 the loaded frames are in `grf_frame_ok`, while `cop_frame_ok` and `tau_frame_ok` exclude them.
-- Han2023 yoga / dance: a few extreme-torque frames of kinematic origin (`tau_frame_ok` excludes them).
-- vanderZee2022 S09 has no upper-body markers (`qc_upper_body_unobserved`); AddB pass 0 and pass 2 arms differ by about 200 mm there and the SKEL arms, trunk and head are unconstrained (masked).
-- The scapula DOFs are pinned at their bounds in most fits (`qc_skel_scapula_pinned`); scapula elevation sits on its +-0.1 rad bound (size unsourced, SKEL issue #19) in many kinematics fits. Mask scapula DOFs in losses.
-- SKEL left ankle axis (SKEL issue #45, kept upstream): `ankle_angle_l` / `subtalar_angle_l` are not the mirror of the right DOFs and the fit compensates with subtalar_l. Do not mirror motions by swapping L/R SKEL DOFs; compare left and right ankles with the AddB q (`q_kin`, `q_gt`). Read the poses with official SKEL (a SKEL with the issue #45 fix moves the left toes by about 22 mm at p95).
-- Joint-limit bounds of the fit are left/right asymmetric for shoulder_y and pro_sup (unsourced kin_skel values, kept).
-- Pelvis joint error is higher than in the first v1.2 fit (median about 2 mm) after the knee weight change; the SKEL femur is shorter than the AddB femur (shape-step limitation).
-- Head post-fit: a few trials sit on a neck limit for many frames (`qc_head_at_limit_frac_*`); trials without head markers keep the head rigid with the thorax (neck line 3-10 deg forward of the markers in head-marker studies).
-- Non-arm fit-only spikes (head, spine) exist in a minority of trials; they are masked per joint group in `fit_event_ok_*`, not repaired. Head post-fit steps > 0.5 rad per frame are masked in the head column.
-- Dynamics-pass target repair: on repaired trials the Newton consistency of `poses_dyn` with the GRF dropped by more than 0.02 (correlation) in a minority of trials and the lower-body error rose by more than 1 mm in some; accepted. `qc_skel_vs_qgt_err_mm` compares with `q_gt`, not with the repaired target.
-- Some dyn-pass arm events listed by the 2026-10-07 diagnosis refer to the dyn fit before the 2026-10-08/09 target repair; they are kept in `arm_event_ok_dyn` (conservative), together with the events of the re-scan of the final fits.
-- Carter2023 running: in some trials AddB marks the flight frames as missing GRF (`grf_valid_mask` False), so force labels and the T-GRF benchmark cover stance frames only there (most trials keep the flight frames valid with zero force).
-- `floor_height_m` is the loaded step height on stairs / step activities; no floor normal is shipped.
-- `visualize.py` needs the addb2skel package (SKEL rendering utilities), which is not distributed with ForceBody; reading the data needs only numpy.
-- Release verification left three small deviations: in one trial the fit joint error recomputed from the stored float32 `joints` / `addb_joints_kin` differs from the stored `qc_skel_fit_err_mm` by 0.054 mm (tolerance 0.05 mm, so one of 10,386 trials fails the independent reproduction check); the median lag between GRF and kinematic toe-off events is -74.5 ms for Uhlrich2023 (all other studies -50 to 0 ms), just outside the -70 to +10 ms window used as a sanity range.
-- No acceleration filter was applied to the kinematics-pass target: `poses` keep a small frame-to-frame wobble on trials whose AddB pass-0 inverse kinematics is noisy. The dynamics-pass target is smoother (AddB dynamics pass; repaired targets use the AddB acceleration-minimizing filter).
-- Name clash: `chair_contact` in manifest.csv is the trial-level protocol flag (a chair is used in the trial), while `chair_contact` inside the trial file is the frame-level [T] seated mask of the Falisse2017 chair channel (all False without a chair channel). Use `qc_chair_channel_active` for the trial-level summary of the frame mask.
-- CoP placement at low load: frames where a foot channel is loaded (vertical force above 5% BW) and its CoP lies more than 0.15 m from both feet are not all flagged. A scan of the release found 3,227 GRF-valid such frames in 664 trials with `cop_frame_ok` True and `cop_off_foot` False; mask CoP losses by load if this matters.
-- Han2023 `sit` (12 trials) and `sit-to-stand` (2 trials): in the frames a posture rule marks as seated, the foot GRF stays near 1 BW (median 0.999 BW) and there is no seat force channel, so either the seat load is not measured or the label does not describe a loaded seated phase. The labels were not changed.
-- Treadmill belt residual: on treadmill trials the stance foot is not perfectly stationary after the belt motion is removed with a kinematic estimate of the horizontal belt speed (and the protocol grade for the vertical component): the median stance-foot speed is about 0.05-0.10 m/s depending on the trial sample and pose set, against about 0.02-0.05 m/s overground.
-- SKEL knee clamped at full extension (T2M audit R11): in many walking trials the SKEL knee sits on its 0 bound while the AddB target knee is flexed about 3-8 deg, more often on the left. Flagged per frame in `knee_clamp_frame_kin` / `_dyn` since 1.2.1 (1,061 trials above 10% of frames in `poses`); not refitted. On kin_retimed trials `knee_clamp_frame_dyn` compares `poses_dyn` with `q_gt`, not with the retimed kinematic target.
-- Stairs (22 trials in activity class stairs): no per-step floor is shipped. `floor_height_m` is one loaded-step height per trial, and one fitted floor plane per trial (as in the T2M encoders) treats a staircase as a ramp, so heights above that floor are not step-relative (T2M audit R15).
-- Moore2015 standing (29 trials): in the wide-stance phases the feet sit 2-4 cm below the trial median floor level on about 40% of frames; whether this is real penetration or a floor estimate set too high is not resolved (T2M audit R18).
-- Pathological persons (Fregly2012 TKA 78 trials, Li2021 stroke 65 trials): the `caption_*` phrases never mention the pathology, and the Li2021_S05 fits have about 1.8 times the healthy fit error (standing 26.6 mm vs 14.7 mm) (T2M audit R21). Use them as an out-of-distribution stratum (`eval_stratum`).
-- Trials above 100 Hz (Han2023 and some Carter2023 at 250 Hz, Tiziana2019 at 201 Hz) ship on their native grid. Resampling them to 100 Hz without a low-pass filter (as the T2M encoders do) aliases force-plate noise (Han2023: 7-30 N RMS below 50 Hz; peaks are kept) (T2M audit R22).
-- vanderZee2022 walking: the median peak hip flexion torque is 1.95 N m/kg, against 1.0 (Carter2023) and 1.36 (Moore2015); the cause is not identified (possibly the plate cross-talk above) (T2M audit R23).
-- `q_kin` beyond 2 pi on a shoulder DOF in a few trials (`qc_q_kin_wrap`, T2M audit R12): an AddB Euler branch of the pass-0 target, not unwrapped; the arm frames are masked in `arm_event_ok_kin` (1.2.1). The mask covers only the frames beyond 2 pi (+-0.1 s); in some of these trials the wrapped stretch is wider (an arm DOF of `q_kin` more than pi/2 from `q_gt` outside the mask), so skip arm losses on the whole trial if in doubt.
-- Constant-labelled treadmill belts that change speed (`qc_belt_speed_change`, `_suspected`; T2M audit R16) and segments whose label does not match the motion (`label_conflict_codes` SEGMENT_MOTION_MISMATCH; R17) are flagged in 1.2.1; trials and labels are unchanged.
+```python
+import numpy as np
+d = np.load("ForceBody/trials/Moore2015/S10/Moore2015_S10_walk_014.npz", allow_pickle=True)
+tau = d["tau_selfconsistent"] / d["mass_kg_dynamics"]   # N m / kg
+```
 
-## License and attribution
+For force or torque prediction, take motion input from `poses` (kinematics pass) only. See `DETAILS.md` and the GitHub loader.
 
-The ForceBody data are released under the Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0). Commercial use is not permitted.
+## License
 
-- Fields derived from AddBiomechanics (forces, AddB kinematics, torques, uncertainty, metadata) build on the AddBiomechanics dataset (CC BY 4.0). Cite AddBiomechanics and every source study you use.
-- SKEL-derived fields (`poses*`, `trans*`, `joints*`, `betas`, `skel_gender`) are also subject to the SKEL model license, which allows non-commercial scientific research only. Building meshes from these fields requires the SKEL model, which you obtain from its authors under their license.
-- The code in this release (`forcebody_io.py`, `visualize.py`, `benchmark/`) and in the GitHub repository is released under the MIT license.
+Data under **CC BY-NC 4.0** (non-commercial). SKEL-derived fields also follow the [SKEL license](https://skel.is.tue.mpg.de/). Code on GitHub under MIT. Please cite AddBiomechanics and the source studies you use.
 
-## How to cite
+## Citation
 
 ```bibtex
-@inproceedings{forcebody,
-  title = {ForceBody},
-  note = {citation to be completed at publication}
-}
-@inproceedings{werling2024addbiomechanics,
-  title = {AddBiomechanics Dataset: Capturing the Physics of Human Motion at Scale},
-  booktitle = {ECCV},
-  year = {2024},
-  doi = {10.1007/978-3-031-73223-2_27}
-}
-@article{werling2023addbiomechanics,
-  title = {AddBiomechanics: Automating model scaling, inverse kinematics, and inverse dynamics from human motion data through sequential optimization},
-  journal = {PLOS ONE},
-  year = {2023},
-  doi = {10.1371/journal.pone.0295152}
+@inproceedings{kwon2026forcebody,
+  title     = {ForceBody: Force-Paired Parametric Body Motion with Torque Uncertainty},
+  author    = {Kwon, Joonwoo and Zhang, Yufei and Liu, Xiaoming and Cui, Zijun},
+  booktitle = {Advances in Neural Information Processing Systems (NeurIPS), Evaluations and Datasets Track},
+  year      = {2026}
 }
 ```
-
-## Versions
-
-| version | date | note |
-|---|---|---|
-| 1.0.0-reviewed | 2026-05-07 | reviewed build (paper numbers) |
-| internal v1 | 2026-08-31 | internal build |
-| internal 1.1 | 2026-09-27 | internal build (frame and timebase fixes) |
-| 1.2.0 | 2026-10-11 | first frozen 1.2 build (first build 2026-10-09); superseded by 1.2.1 (QC mask erratum) |
-| 1.2.1 | 2026-10-12 | 1.2.0 with corrected QC masks and flags (pose, force and torque arrays unchanged) |
-| 1.3.0 | 2026-10-29 | this release: Hamner2013 study id (40 trial keys renamed, map shipped), `sex_resolved` corrected, benchmark results, documentation; arrays otherwise identical to 1.2.1, see CHANGELOG.md |
-
-## Maintenance
-
-Issues and corrections are tracked per version in CHANGELOG.md; replaced arrays are kept in an internal v1.1 provenance archive (not uploaded), so every change can be traced back to v1.1.
-