sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2: payload batch 4/7

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+          "p90_m": 0.010572088137269021,
+          "max_m": 0.014930615201592445,
+          "beyond_2delta_fraction": 0.15590973646836043,
+          "at_cap_fraction": 0.0
+        },
+        {
+          "view": 3,
+          "count": 4120,
+          "median_m": 0.010542564559727907,
+          "p90_m": 0.017982049286365508,
+          "max_m": 0.020186036825180054,
+          "beyond_2delta_fraction": 0.541504854368932,
+          "at_cap_fraction": 0.0
+        }
+      ],
+      "round": 1,
+      "relative_loss_change": 0.9902507890050455
+    },
+    "arclength_soft_bounds_m": [
+      0.5830000042915344,
+      0.5849999785423279
+    ],
+    "arclength_outside_soft_bounds_m": 0.00042259693145751953
+  },
+  "geometry": {
+    "vertex_count": 1728,
+    "triangle_count": 3456,
+    "checks": {
+      "euler_characteristic": 0,
+      "watertight": true,
+      "components": 1,
+      "winding_consistent": true,
+      "signed_volume_m3": 3.957752570888942e-05,
+      "minimum_outward_normal_dot_m": 0.004522543676238979,
+      "degenerate_triangles": 0,
+      "self_intersecting": false,
+      "maximum_radius_error_m": 6.7956049025832965e-09,
+      "maximum_diameter_error_m": 1.3591209805166593e-08,
+      "bishop_seam_error": 0.0,
+      "minimum_nonadjacent_centerline_distance_m": 0.006287800352442404,
+      "triangle_area_m2": {
+        "min": 2.0564709284978463e-06,
+        "median": 4.852855653044753e-06,
+        "mean": 4.9942245479456206e-06,
+        "max": 6.959894928209357e-06,
+        "density_max_over_min": 3.3843877060266676
+      },
+      "bounds_m": [
+        [
+          -0.02601274661719799,
+          -0.244719460606575,
+          0.007835153490304947
+        ],
+        [
+          0.101390041410923,
+          0.007373368367552757,
+          0.03908699378371239
+        ]
+      ],
+      "radius_m": 0.00475,
+      "step_t": 0.125,
+      "step_angle_deg": 30,
+      "overlap_rule": "surface_intersection",
+      "open3d_reported_intersecting_pairs": 0,
+      "confirmed_intersecting_pairs": [],
+      "passed": true,
+      "orientation_flipped": true
+    }
+  },
+  "appearance_seed_counts": {
+    "observed": 18412,
+    "mesh": 103680,
+    "total": 122092,
+    "mesh_to_observed": 5.631110145557245
+  },
+  "vertex_colors": {
+    "observed_vertices": 1089,
+    "filled_vertices": 639
+  },
+  "mechanical_population": {
+    "particle_count": null,
+    "total_unit_mass": null,
+    "status": "not produced by the prior run; no post-prior mechanics are evaluated here"
+  },
+  "source_code": {
+    "commit": "d1d2f1381470138dfbb3c58d448e53bfed1e0d7e",
+    "u_pin": "81c718790a37e5e0102eb77af2c6edd34a9db25f"
+  },
+  "media": {
+    "full_rotation": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/tube/orbit.mp4",
+    "geometry_depth_cloud": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/tube/tube_scale_views.png",
+    "depth_offset_diagnostic": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/inputs/depth_offset.png",
+    "residual_histograms": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/spline/residual_histograms.png",
+    "color_visibility_fill": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/colors/visibility_and_fill.png",
+    "hybrid_seed_populations": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/review/hybrid/combined.png",
+    "derived_coverage": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/derived/derived_coverage.png"
+  },
+  "sources": {
+    "manifest": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/manifest.json",
+    "fit": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/steps/fit.json",
+    "geometry_checks": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/tube/tube_checks.json",
+    "reference_views": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/inputs/reference_views.json",
+    "reprojection": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b/spline/reprojection.json",
+    "tracking_summary": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/summary.json",
+    "frames": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/frames_waft.npz"
+  }
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_lower_curvature_v2/PRIOR_REVIEW_c6a_v1.md

@@ -0,0 +1,71 @@
+# session_20260921_233248_177244 — prior approval pending
+
+Saved C2 **bike_chain** prior evidence (radius 4.75 mm). Agent numerical and visual review is complete. This candidate is not accepted; all old chain-prior acceptances remain revoked. This packet reports the observations and tradeoffs below and grants no acceptance.
+
+Initial reference frames are the saved nearest-camera observations of the first 30 Hz sample. The local row, converted frame, native-container frame and capture clock remain distinct in [the metrics JSON](<prior_metrics.json>).
+
+| Camera | Local / converted / native | Centerline / geometry / native input |
+|---|---|---|
+| 12540311 | 0 / 208 / 209 | [centerline](<../prior_chain_lower_curvature_v2/review/spline/centerline_0_with_masks.png>) · [tube](<../prior_chain_lower_curvature_v2/review/tube/silhouette_0_unmasked.png>) · [geometry + mask](<../prior_chain_lower_curvature_v2/review/tube/silhouette_0_with_masks.png>) · [RGB/depth](<../prior_chain_lower_curvature_v2/review/inputs/view_0_12540311.png>) |
+| 12933256 | 1 / 208 / 209 | [centerline](<../prior_chain_lower_curvature_v2/review/spline/centerline_1_with_masks.png>) · [tube](<../prior_chain_lower_curvature_v2/review/tube/silhouette_1_unmasked.png>) · [geometry + mask](<../prior_chain_lower_curvature_v2/review/tube/silhouette_1_with_masks.png>) · [RGB/depth](<../prior_chain_lower_curvature_v2/review/inputs/view_1_12933256.png>) |
+| 17736741 | 0 / 208 / 209 | [centerline](<../prior_chain_lower_curvature_v2/review/spline/centerline_2_with_masks.png>) · [tube](<../prior_chain_lower_curvature_v2/review/tube/silhouette_2_unmasked.png>) · [geometry + mask](<../prior_chain_lower_curvature_v2/review/tube/silhouette_2_with_masks.png>) · [RGB/depth](<../prior_chain_lower_curvature_v2/review/inputs/view_2_17736741.png>) |
+| 23007103 | 0 / 208 / 209 | [centerline](<../prior_chain_lower_curvature_v2/review/spline/centerline_3_with_masks.png>) · [tube](<../prior_chain_lower_curvature_v2/review/tube/silhouette_3_unmasked.png>) · [geometry + mask](<../prior_chain_lower_curvature_v2/review/tube/silhouette_3_with_masks.png>) · [RGB/depth](<../prior_chain_lower_curvature_v2/review/inputs/view_3_23007103.png>) |
+
+[Full rotation video](<../prior_chain_lower_curvature_v2/review/tube/orbit.mp4>) · [Geometry and depth cloud](<../prior_chain_lower_curvature_v2/review/tube/tube_scale_views.png>) · [Residual histograms](<../prior_chain_lower_curvature_v2/review/spline/residual_histograms.png>) · [Depth offset diagnostic](<../prior_chain_lower_curvature_v2/review/inputs/depth_offset.png>)
+
+Saved fit: **1 stage-1 rounds**, stop `gradient_tolerance`; final length **585.411 mm**, maximum curvature **105.489/m**, final gradient norm **6.24481e-05**. Soft length bounds are 583.000–585.000 mm; distance outside those bounds is 0.411 mm.
+
+Saved geometry checks report `passed=True`: **1728 mesh vertices / 3456 triangles**, 1 component(s), `watertight=True`, `self_intersecting=False`. [Full geometry checks](<../prior_chain_lower_curvature_v2/tube/tube_checks.json>).
+
+The following 3D residuals are lifted-depth point distances to the **centerline**, not measured reconstruction errors. The centerline-in-mask fraction is a separate saved diagnostic; it is not silhouette IoU or a visual quality decision.
+
+| Camera | Median / p90 3D residual (mm) | Visible centerline inside mask | Native depth and visibility evidence |
+|---|---|---|---|
+| 12540311 | 8.541 / 13.838 | 99.02% | [Full native video](<../review_v1/12540311/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/12540311/12540311_visibility_certainty.png>) · [Support/rejections](<../review_v1/12540311/support_and_rejections.png>) · [Paired depth](<../review_v1/12540311/paired_depth.png>) |
+| 12933256 | 5.780 / 20.010 | 94.89% | [Full native video](<../review_v1/12933256/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/12933256/12933256_visibility_certainty.png>) · [Support/rejections](<../review_v1/12933256/support_and_rejections.png>) · [Paired depth](<../review_v1/12933256/paired_depth.png>) |
+| 17736741 | 6.130 / 10.571 | 97.90% | [Full native video](<../review_v1/17736741/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/17736741/17736741_visibility_certainty.png>) · [Support/rejections](<../review_v1/17736741/support_and_rejections.png>) · [Paired depth](<../review_v1/17736741/paired_depth.png>) |
+| 23007103 | 10.549 / 18.010 | 98.52% | [Full native video](<../review_v1/23007103/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/23007103/23007103_visibility_certainty.png>) · [Support/rejections](<../review_v1/23007103/support_and_rejections.png>) · [Paired depth](<../review_v1/23007103/paired_depth.png>) |
+
+The saved statistical filter used 20 neighbours / 2 sigma and kept **18412 of 18889** eroded points. The run used `waft_stereo_dav2l5`, 2 px erosion, a 400-round budget and reprojection weight **4**.
+
+Appearance initialization contains **18412 observed + 103680 mesh-derived = 122092 seeds**. Vertex colors are observed for 1093 mesh vertices and median-filled for 635. Mesh vertices and appearance seeds are not mechanical particles. No post-prior mechanical population or unit-mass total is supplied by this prior run; trained appearance and physical fitting are separate stages.
+
+[Appearance seed populations](<../prior_chain_lower_curvature_v2/review/hybrid/combined.png>) · [Observed and filled colors](<../prior_chain_lower_curvature_v2/review/colors/visibility_and_fill.png>) · [30 Hz observation coverage](<../review_v1/derived/derived_coverage.png>)
+
+[Manifest](<../prior_chain_lower_curvature_v2/manifest.json>) · [Fit settings and metrics](<../prior_chain_lower_curvature_v2/steps/fit.json>) · [Reference observations](<../prior_chain_lower_curvature_v2/inputs/reference_views.json>) · [Tracking/lift summary](<../review_v1/summary.json>)
+
+The agent inspected 21 actual initial-prior panels and 9 orbit samples. [Exact findings and paired metrics](<agent_findings.json>) retain the coverage. No owner approval, case status, mechanics or appearance authorization is changed.
+
+## Comparison with the retained M18 baseline
+
+Both owner-authorized candidates are complete and reviewed. **Neither is accepted, and all old chain-prior acceptances remain revoked.** Lower curvature uses M18 / 5e-10 / reprojection 4; stronger reprojection uses M18 / 5e-9 / reprojection 8. Every other fit, input and geometry setting matches the designated baseline.
+
+| Run | Mean 2D distance (mm) | Mean 3D distance (mm) | Length (mm) | Soft upper excess (mm) | Max curvature (/m) | Surface z range (mm) |
+|---|---:|---:|---:|---:|---:|---|
+| retained_M18_baseline | 3.230300 | 8.389743 | 585.422575 | 0.422597 | 105.469978 | 7.835153 to 39.086994 |
+| lower_curvature | 3.230262 | 8.390043 | 585.410774 | 0.410795 | 105.489342 | 7.833285 to 39.094202 |
+| stronger_reprojection | 3.093955 | 9.176348 | 585.802734 | 0.802755 | 101.728271 | 6.917458 to 38.935114 |
+
+Lowering curvature weight from 5e-9 to 5e-10 produces effectively unchanged visible geometry and raw residuals under the unchanged solver. It is not evidence that a smaller penalty improves this case.
+
+Doubling reprojection weight improves the mean mask-to-centerline distance in every camera, with small visible contour shifts; pooled point-to-centerline distance and soft-length excess increase. This is a measured tradeoff, not a physical-accuracy result or global winner.
+
+The 2D metric is the equal-view mean visible-mask-pixel distance to the projected centerline; it is not silhouette IoU. The 3D metric is pooled lifted-point distance to the centerline; it is not tube-surface error or ground-truth accuracy. Differently weighted total objectives are not ranked. The results have no new noise or significance bound.
+
+Both candidates follow the exposed narrow chain loop in all four views. The upper grasp remains rounded and hidden closures project across the two hands; camera 12933256 has extensive foreground forearm/sleeve occlusion. This is inferred closed-loop geometry, not a directly measured hidden contour or proof of physical hand penetration.
+
+The two long arcs and grasp closures remain visually very similar across baseline and both candidates. The stronger-reprojection arm has small contour shifts, most visible along the exposed cameras 12540311 and 23007103 arcs; neither arm provides a dramatic visual correction of the hidden shape.
+
+Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse.
+
+The 4.75 mm radius circular tube approximates the linked chain. Ring samples are tube cross-sections, not individual rollers, plates, link gaps or articulation. The object-to-table depth offsets remain uncorrected.
+
+This candidate stops after 1 outer round(s) at `gradient_tolerance`, gradient norm 6.2448096e-05. Soft length and curvature thresholds remain penalties, not hard feasibility limits. Its tube has 144 rings, 1728 vertices and 3456 triangles at 4.75 mm radius; the saved surface-intersection checks pass. Colors are observed for 1093 vertices and median-filled for 635. Hybrid seeds remain 18,412 observed + 103,680 mesh-derived = 122,092; these are appearance seeds, not mechanical particles or mass.
+
+Actual inspection covered 21 panels per candidate: four inputs, four masked centerlines, eight masked/unmasked silhouettes, and scale/depth cloud, depth offset, residual histograms, colors/fill, hybrid populations. Nine orbit samples 0, 4, 8, 13, 17, 21, 26, 30, 35 of 36 at 12 fps were inspected per candidate. The four retained baseline centerline overlays were also inspected. This is bounded sampled viewing, not continuous playback.
+
+Both hands participate: the retained pre-prior reference has 30 controls (14 hand_A, 16 hand_B), selected after the inclusive 4 cm initial gate; maximum initial distance 39.913 mm. Camera 12933256 loses substantial chain support behind the foreground arm. Initial cloud scatter and camera-dependent depth disagreement remain, and missing 3D observations remain NaN. The earlier reference inspection sampled 13 times per view; it does not provide every-frame physical-fitting clearance. [Reference review](<../review_v1/REVIEW.md>). These initial priors do not clear later observations for physical fitting.
+
+[Other candidate](<../prior_review_chain_stronger_reprojection_v2/PRIOR_REVIEW_c6a_v1.md>) · [Numerical checks](<numeric_prior_review.json>) · [Exact visual findings](<agent_findings.json>).
+
+All six scientific stages and the single explicit-run packager/check returned zero. All 27 reused input payloads match the designated baseline byte-for-byte, and the copied inputs exclude the derived shape GLB. Both designated old M18 baseline fits and manifests remain unchanged. Saved controls and all seven numerical array families are finite; per-view residual quantiles, geometry radius/bounds, vertex colors and hybrid correspondence were checked. Only the assigned new review packets and unique scratch were written; no source, scientific product, global status or owner record was changed.

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_lower_curvature_v2/agent_findings.json

@@ -0,0 +1,609 @@
+{
+  "case_id": "233248",
+  "candidate": "lower_curvature",
+  "reviewed_utc": "2026-10-28T22:50:57.811051+00:00",
+  "scope": {
+    "goal": "Review both owner-authorized parameter candidates and compare with the retained M18 prior",
+    "done_when": "Per candidate: six science results zero, one package/check,21 actual panels+9 orbit samples, numerical identity/geometry checks and paired findings",
+    "non_goals": [
+      "No science execution or modified scientific products",
+      "No global selection or restoration of revoked acceptances",
+      "No mechanics, trained appearance or physical fitting"
+    ],
+    "validation": "Saved stage results, exact requested settings and unchanged remaining settings, 27 input-byte comparisons, both designated baseline identities, numerical arrays, actual images, and linked packet"
+  },
+  "job": {
+    "case_id": "233248",
+    "session_id": "session_20260921_233248_177244",
+    "case": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747",
+    "prep": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1",
+    "candidate": "lower_curvature",
+    "run": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2",
+    "review": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_review_chain_lower_curvature_v2",
+    "baseline": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b",
+    "settings": {
+      "control_count": 18,
+      "lambda_curvature_cost": 5e-10,
+      "reprojection_weight": 4.0
+    },
+    "baseline_manifest_sha256": "6bae8ff984f579cef97ccf1543097d97047be94573a7e372c60f6719799e5e7d",
+    "baseline_fit_sha256": "3365dec0010a7eea2936d291f75511051dd6adf4afb8b668de03438306decb30"
+  },
+  "owner_prior_approval": "not accepted; old chain-prior acceptances remain revoked",
+  "full_sequence_physical_fitting_clearance": false,
+  "readiness": "both_candidates_ready_for_owner_comparison_with_preserved_limitations",
+  "inspected_images_relative_to_run": [
+    "review/inputs/view_0_12540311.png",
+    "review/inputs/view_1_12933256.png",
+    "review/inputs/view_2_17736741.png",
+    "review/inputs/view_3_23007103.png",
+    "review/spline/centerline_0_with_masks.png",
+    "review/spline/centerline_1_with_masks.png",
+    "review/spline/centerline_2_with_masks.png",
+    "review/spline/centerline_3_with_masks.png",
+    "review/tube/silhouette_0_unmasked.png",
+    "review/tube/silhouette_1_unmasked.png",
+    "review/tube/silhouette_2_unmasked.png",
+    "review/tube/silhouette_3_unmasked.png",
+    "review/tube/silhouette_0_with_masks.png",
+    "review/tube/silhouette_1_with_masks.png",
+    "review/tube/silhouette_2_with_masks.png",
+    "review/tube/silhouette_3_with_masks.png",
+    "review/tube/tube_scale_views.png",
+    "review/inputs/depth_offset.png",
+    "review/spline/residual_histograms.png",
+    "review/colors/visibility_and_fill.png",
+    "review/hybrid/combined.png"
+  ],
+  "orbit_inspection": {
+    "source": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/orbit.mp4",
+    "reported_frames": 36,
+    "fps": 12.0,
+    "selected_frame_indices": [
+      0,
+      4,
+      8,
+      13,
+      17,
+      21,
+      26,
+      30,
+      35
+    ],
+    "method": "Nine selected direct reads; no continuous playback or full decode claim",
+    "visual_inspection_pending": false,
+    "visual_inspection_complete": true,
+    "observations": "Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse."
+  },
+  "baseline_additional_visual_inspection": [
+    "review/spline/centerline_0_with_masks.png",
+    "review/spline/centerline_1_with_masks.png",
+    "review/spline/centerline_2_with_masks.png",
+    "review/spline/centerline_3_with_masks.png"
+  ],
+  "common_visual_findings": [
+    "Both candidates follow the exposed narrow chain loop in all four views. The upper grasp remains rounded and hidden closures project across the two hands; camera 12933256 has extensive foreground forearm/sleeve occlusion. This is inferred closed-loop geometry, not a directly measured hidden contour or proof of physical hand penetration.",
+    "The two long arcs and grasp closures remain visually very similar across baseline and both candidates. The stronger-reprojection arm has small contour shifts, most visible along the exposed cameras 12540311 and 23007103 arcs; neither arm provides a dramatic visual correction of the hidden shape.",
+    "Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse.",
+    "The 4.75 mm radius circular tube approximates the linked chain. Ring samples are tube cross-sections, not individual rollers, plates, link gaps or articulation. The object-to-table depth offsets remain uncorrected."
+  ],
+  "candidate_interpretation": "Lowering curvature weight from 5e-9 to 5e-10 produces effectively unchanged visible geometry and raw residuals under the unchanged solver. It is not evidence that a smaller penalty improves this case.",
+  "paired_metrics": [
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+        "mean_2d_mask_to_centerline_mm": -0.13634492038208323
+      }
+    }
+  ],
+  "comparison_rule": "Common raw diagnostics and visual evidence; differently weighted total objectives are not ranked. No noise/significance bound is inferred.",
+  "temporal_and_hand_context": "Both hands participate: the retained pre-prior reference has 30 controls (14 hand_A, 16 hand_B), selected after the inclusive 4 cm initial gate; maximum initial distance 39.913 mm. Camera 12933256 loses substantial chain support behind the foreground arm. Initial cloud scatter and camera-dependent depth disagreement remain, and missing 3D observations remain NaN. The earlier reference inspection sampled 13 times per view; it does not provide every-frame physical-fitting clearance.",
+  "reference_review_record": {
+    "case": "233248",
+    "window_anchor_inclusive": [
+      208,
+      747
+    ],
+    "reviewer": "chain preparation agent",
+    "reviewed_utc": "2026-10-28T13:08:53.813975+00:00",
+    "coverage": {
+      "RGB_tracking_sheets": {
+        "cameras": [
+          "12540311",
+          "12933256",
+          "17736741",
+          "23007103"
+        ],
+        "native_times_per_camera": [
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+          45,
+          90,
+          135,
+          180,
+          225,
+          270,
+          315,
+          360,
+          405,
+          450,
+          495,
+          539
+        ],
+        "sheets_inspected": 12,
+        "source_indices": "Each camera rgb_sample_index.json records converted/native indices, timestamps and crops."
+      },
+      "native_RGB_WAFT_panels": {
+        "12540311": [
+          135
+        ],
+        "12933256": [
+          135
+        ],
+        "17736741": [
+          315
+        ],
+        "23007103": [
+          135
+        ]
+      },
+      "all_time_plots": [
+        "tracker_visibility_and_certainty (all four cameras)",
+        "support_and_rejections (all four cameras)",
+        "paired_native_WAFT_depth (all four cameras)",
+        "derived_coverage"
+      ],
+      "derived_geometry": [
+        "object_and_hand_xy.png",
+        "source_center_graph.png"
+      ]
+    },
+    "observations": [
+      "At all 13 sampled times in each of four views, admitted object support follows the visible chain and hand support follows the physical right and left hands; no broad background drift or hand-identity swap is visible.",
+      "Object support remains nonzero in every native view throughout the selected span. Camera 12933256 has substantially less support during foreground-arm occlusion (55\u2013248 admitted native object points); hidden and rejected predictions remain separate from measurements.",
+      "All 30 selected controls remain valid at every derived sample: 14 hand_A and 16 hand_B. The global FPS population was selected after the unchanged inclusive 4 cm initial gate; maximum selected distance is 39.91314803066454 mm. No hand quota was imposed.",
+      "The 541-sample exact 30 Hz derived bundle retains 707 mesh-free object representatives with 430\u2013707 visible per sample. Initial, middle and final XY views preserve the chain configuration; the initial cloud has measurable scatter. No isolated object node or unattached control is reported in the source-center graph.",
+      "Native-versus-WAFT depth differences vary by camera and time. These are paired same-pixel diagnostics, not depth truth; no depth replacement, gap filling, point movement or threshold change was applied."
+    ],
+    "array_checks": {
+      "raw_queries_and_native_times_unchanged": true,
+      "raw_TAP_coordinates_logits_certainty_finite": true,
+      "lifted_valid_samples_finite": true,
+      "missing_3d_samples_remain_NaN": true,
+      "all_role_and_human_masks_covered": true,
+      "selected_controls_all_time_valid": true,
+      "participating_hands": [
+        "hand_A",
+        "hand_B"
+      ],
+      "selected_controls_per_hand": {
+        "hand_A": 14,
+        "hand_B": 16
+      },
+      "controller_initial_distance_m_max": 0.03991314803066454,
+      "initial_object_xyz_m_min_max": [
+        [
+          -0.03047075106504542,
+          -0.24886165519310022,
+          -0.0019702112750242234
+        ],
+        [
+          0.09300282201994965,
+          0.023481816239153824,
+          0.04389297479033285
+        ]
+      ],
+      "unit_masses_and_model_arrays_equal_saved_observations": true
+    },
+    "initialization": {
+      "nodes": 707,
+      "controls": 30,
+      "total_source_mass_units": 707.0,
+      "source_center_graph": {
+        "object_springs": 10772,
+        "controller_springs": 724,
+        "object_rest_min_max_m": [
+          0.000310589064611122,
+          0.019994795322418213
+        ],
+        "controller_rest_min_max_m": [
+          0.010204235091805458,
+          0.03995547443628311
+        ],
+        "isolated_object_nodes": 0,
+        "attached_object_nodes": 148,
+        "controls_without_attachment": 0,
+        "attachments_by_hand": {
+          "hand_A": 371,
+          "hand_B": 353
+        }
+      }
+    },
+    "interpretation": "No material blocker found to preparing the requested current-C2 bike-chain prior from these accepted inputs. This is agent inspection, not owner acceptance of a future prior or appearance. The mesh-free node count is pre-prior inspection, not final mechanics.",
+    "limitations": [
+      "Visual review sampled 13 times per view, not every video frame.",
+      "Tracker visibility and certainty are not geometric accuracy.",
+      "Initial lifted scatter and multiview depth differences remain; the requested prior geometry, silhouette/depth diagnostics and owner review are still required."
+    ],
+    "full_window_media": {
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+      "12933256": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/12933256/rgb_waft_depth_full_window.mp4",
+      "17736741": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/17736741/rgb_waft_depth_full_window.mp4",
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+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_lower_curvature_v2/orbit_frames.json

@@ -0,0 +1,20 @@
+{
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+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_lower_curvature_v2/packet_validation.json

@@ -0,0 +1,8 @@
+{
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+  "panels_inspected": 21,
+  "orbit_samples_inspected": 9,
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+  "no_acceptance": true
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_lower_curvature_v2/prior_metrics.json

@@ -0,0 +1,436 @@
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+        "paired_common_min_max": [
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+        "geometry_overlay": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/silhouette_2_unmasked.png",
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+        "initial_rgb_depth": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/inputs/view_2_17736741.png",
+        "native_rgb_depth_video": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/17736741/rgb_waft_depth_full_window.mp4",
+        "visibility_certainty": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/17736741/17736741_visibility_certainty.png",
+        "support_rejections": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/17736741/support_and_rejections.png",
+        "paired_depth": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/17736741/paired_depth.png"
+      }
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+      "visible_centerline_inside_mask_fraction": 0.985207100591716,
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+        "geometry_overlay": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/silhouette_3_unmasked.png",
+        "geometry_with_mask": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/silhouette_3_with_masks.png",
+        "initial_rgb_depth": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/inputs/view_3_23007103.png",
+        "native_rgb_depth_video": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/23007103/rgb_waft_depth_full_window.mp4",
+        "visibility_certainty": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/23007103/23007103_visibility_certainty.png",
+        "support_rejections": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/23007103/support_and_rejections.png",
+        "paired_depth": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/23007103/paired_depth.png"
+      }
+    }
+  ],
+  "recipe": {
+    "depth_source": "waft_stereo_dav2l5",
+    "mask_erosion_px": 2,
+    "filter": {
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+    "max_rounds": 400,
+    "reprojection": {
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+      "mask": "accepted object outside hand/occluder union",
+      "view_aggregation": "equal view means",
+      "distance": "metric image plane using per-view median visible belt depth and fx/fy",
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+    },
+    "solver": {
+      "solver_type": "lbfgs",
+      "linesearch_type": "zoom",
+      "max_linesearch_steps": 10,
+      "grad_norm_tolerance": 0.0001,
+      "max_iter": 25
+    },
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+    "stage1_stop": "gradient_tolerance",
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+    "twist": null,
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+        "curvature": 3.580332474939496e-08,
+        "arclength": 1.687527095839414e-08,
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+        35.88040313720703
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+      "curvature_above_max_fraction": 0.408,
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+          "beyond_2delta_fraction": 0.15575193309136814,
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+    "arclength_soft_bounds_m": [
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+      0.5849999785423279
+    ],
+    "arclength_outside_soft_bounds_m": 0.0004107952117919922
+  },
+  "geometry": {
+    "vertex_count": 1728,
+    "triangle_count": 3456,
+    "checks": {
+      "euler_characteristic": 0,
+      "watertight": true,
+      "components": 1,
+      "winding_consistent": true,
+      "signed_volume_m3": 3.9576752429131664e-05,
+      "minimum_outward_normal_dot_m": 0.004522768097808061,
+      "degenerate_triangles": 0,
+      "self_intersecting": false,
+      "maximum_radius_error_m": 7.26683560461211e-09,
+      "maximum_diameter_error_m": 1.39546537901436e-08,
+      "bishop_seam_error": 2.9802322387695312e-08,
+      "minimum_nonadjacent_centerline_distance_m": 0.006300799347888567,
+      "triangle_area_m2": {
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+        "median": 4.858620277644157e-06,
+        "mean": 4.994129334743499e-06,
+        "max": 6.944253042613088e-06,
+        "density_max_over_min": 3.38187933223975
+      },
+      "bounds_m": [
+        [
+          -0.0260089710354805,
+          -0.2447315901517868,
+          0.007833285257220268
+        ],
+        [
+          0.10137023776769638,
+          0.0073817018419504166,
+          0.03909420222043991
+        ]
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+      "radius_m": 0.00475,
+      "step_t": 0.125,
+      "step_angle_deg": 30,
+      "overlap_rule": "surface_intersection",
+      "open3d_reported_intersecting_pairs": 0,
+      "confirmed_intersecting_pairs": [],
+      "passed": true,
+      "orientation_flipped": true
+    }
+  },
+  "appearance_seed_counts": {
+    "observed": 18412,
+    "mesh": 103680,
+    "total": 122092,
+    "mesh_to_observed": 5.631110145557245
+  },
+  "vertex_colors": {
+    "observed_vertices": 1093,
+    "filled_vertices": 635
+  },
+  "mechanical_population": {
+    "particle_count": null,
+    "total_unit_mass": null,
+    "status": "not produced by the prior run; no post-prior mechanics are evaluated here"
+  },
+  "source_code": {
+    "commit": "98ebffe13629edeb0a9b29df973bebc5730d7026",
+    "u_pin": "81c718790a37e5e0102eb77af2c6edd34a9db25f"
+  },
+  "media": {
+    "full_rotation": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/orbit.mp4",
+    "geometry_depth_cloud": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/tube/tube_scale_views.png",
+    "depth_offset_diagnostic": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/inputs/depth_offset.png",
+    "residual_histograms": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/spline/residual_histograms.png",
+    "color_visibility_fill": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/colors/visibility_and_fill.png",
+    "hybrid_seed_populations": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/review/hybrid/combined.png",
+    "derived_coverage": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/derived/derived_coverage.png"
+  },
+  "sources": {
+    "manifest": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/manifest.json",
+    "fit": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/steps/fit.json",
+    "geometry_checks": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/tube/tube_checks.json",
+    "reference_views": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/inputs/reference_views.json",
+    "reprojection": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2/spline/reprojection.json",
+    "tracking_summary": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/summary.json",
+    "frames": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/frames_waft.npz"
+  }
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_stronger_reprojection_v2/PRIOR_REVIEW_c6a_v1.md

@@ -0,0 +1,71 @@
+# session_20260921_233248_177244 — prior approval pending
+
+Saved C2 **bike_chain** prior evidence (radius 4.75 mm). Agent numerical and visual review is complete. This candidate is not accepted; all old chain-prior acceptances remain revoked. This packet reports the observations and tradeoffs below and grants no acceptance.
+
+Initial reference frames are the saved nearest-camera observations of the first 30 Hz sample. The local row, converted frame, native-container frame and capture clock remain distinct in [the metrics JSON](<prior_metrics.json>).
+
+| Camera | Local / converted / native | Centerline / geometry / native input |
+|---|---|---|
+| 12540311 | 0 / 208 / 209 | [centerline](<../prior_chain_stronger_reprojection_v2/review/spline/centerline_0_with_masks.png>) · [tube](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_0_unmasked.png>) · [geometry + mask](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_0_with_masks.png>) · [RGB/depth](<../prior_chain_stronger_reprojection_v2/review/inputs/view_0_12540311.png>) |
+| 12933256 | 1 / 208 / 209 | [centerline](<../prior_chain_stronger_reprojection_v2/review/spline/centerline_1_with_masks.png>) · [tube](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_1_unmasked.png>) · [geometry + mask](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_1_with_masks.png>) · [RGB/depth](<../prior_chain_stronger_reprojection_v2/review/inputs/view_1_12933256.png>) |
+| 17736741 | 0 / 208 / 209 | [centerline](<../prior_chain_stronger_reprojection_v2/review/spline/centerline_2_with_masks.png>) · [tube](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_2_unmasked.png>) · [geometry + mask](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_2_with_masks.png>) · [RGB/depth](<../prior_chain_stronger_reprojection_v2/review/inputs/view_2_17736741.png>) |
+| 23007103 | 0 / 208 / 209 | [centerline](<../prior_chain_stronger_reprojection_v2/review/spline/centerline_3_with_masks.png>) · [tube](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_3_unmasked.png>) · [geometry + mask](<../prior_chain_stronger_reprojection_v2/review/tube/silhouette_3_with_masks.png>) · [RGB/depth](<../prior_chain_stronger_reprojection_v2/review/inputs/view_3_23007103.png>) |
+
+[Full rotation video](<../prior_chain_stronger_reprojection_v2/review/tube/orbit.mp4>) · [Geometry and depth cloud](<../prior_chain_stronger_reprojection_v2/review/tube/tube_scale_views.png>) · [Residual histograms](<../prior_chain_stronger_reprojection_v2/review/spline/residual_histograms.png>) · [Depth offset diagnostic](<../prior_chain_stronger_reprojection_v2/review/inputs/depth_offset.png>)
+
+Saved fit: **1 stage-1 rounds**, stop `gradient_tolerance`; final length **585.803 mm**, maximum curvature **101.728/m**, final gradient norm **8.32896e-05**. Soft length bounds are 583.000–585.000 mm; distance outside those bounds is 0.803 mm.
+
+Saved geometry checks report `passed=True`: **1728 mesh vertices / 3456 triangles**, 1 component(s), `watertight=True`, `self_intersecting=False`. [Full geometry checks](<../prior_chain_stronger_reprojection_v2/tube/tube_checks.json>).
+
+The following 3D residuals are lifted-depth point distances to the **centerline**, not measured reconstruction errors. The centerline-in-mask fraction is a separate saved diagnostic; it is not silhouette IoU or a visual quality decision.
+
+| Camera | Median / p90 3D residual (mm) | Visible centerline inside mask | Native depth and visibility evidence |
+|---|---|---|---|
+| 12540311 | 9.531 / 14.996 | 98.69% | [Full native video](<../review_v1/12540311/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/12540311/12540311_visibility_certainty.png>) · [Support/rejections](<../review_v1/12540311/support_and_rejections.png>) · [Paired depth](<../review_v1/12540311/paired_depth.png>) |
+| 12933256 | 5.980 / 19.623 | 94.81% | [Full native video](<../review_v1/12933256/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/12933256/12933256_visibility_certainty.png>) · [Support/rejections](<../review_v1/12933256/support_and_rejections.png>) · [Paired depth](<../review_v1/12933256/paired_depth.png>) |
+| 17736741 | 6.820 / 11.706 | 98.19% | [Full native video](<../review_v1/17736741/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/17736741/17736741_visibility_certainty.png>) · [Support/rejections](<../review_v1/17736741/support_and_rejections.png>) · [Paired depth](<../review_v1/17736741/paired_depth.png>) |
+| 23007103 | 11.523 / 18.993 | 98.81% | [Full native video](<../review_v1/23007103/rgb_waft_depth_full_window.mp4>) · [Visibility/certainty](<../review_v1/23007103/23007103_visibility_certainty.png>) · [Support/rejections](<../review_v1/23007103/support_and_rejections.png>) · [Paired depth](<../review_v1/23007103/paired_depth.png>) |
+
+The saved statistical filter used 20 neighbours / 2 sigma and kept **18412 of 18889** eroded points. The run used `waft_stereo_dav2l5`, 2 px erosion, a 400-round budget and reprojection weight **8**.
+
+Appearance initialization contains **18412 observed + 103680 mesh-derived = 122092 seeds**. Vertex colors are observed for 1094 mesh vertices and median-filled for 634. Mesh vertices and appearance seeds are not mechanical particles. No post-prior mechanical population or unit-mass total is supplied by this prior run; trained appearance and physical fitting are separate stages.
+
+[Appearance seed populations](<../prior_chain_stronger_reprojection_v2/review/hybrid/combined.png>) · [Observed and filled colors](<../prior_chain_stronger_reprojection_v2/review/colors/visibility_and_fill.png>) · [30 Hz observation coverage](<../review_v1/derived/derived_coverage.png>)
+
+[Manifest](<../prior_chain_stronger_reprojection_v2/manifest.json>) · [Fit settings and metrics](<../prior_chain_stronger_reprojection_v2/steps/fit.json>) · [Reference observations](<../prior_chain_stronger_reprojection_v2/inputs/reference_views.json>) · [Tracking/lift summary](<../review_v1/summary.json>)
+
+The agent inspected 21 actual initial-prior panels and 9 orbit samples. [Exact findings and paired metrics](<agent_findings.json>) retain the coverage. No owner approval, case status, mechanics or appearance authorization is changed.
+
+## Comparison with the retained M18 baseline
+
+Both owner-authorized candidates are complete and reviewed. **Neither is accepted, and all old chain-prior acceptances remain revoked.** Lower curvature uses M18 / 5e-10 / reprojection 4; stronger reprojection uses M18 / 5e-9 / reprojection 8. Every other fit, input and geometry setting matches the designated baseline.
+
+| Run | Mean 2D distance (mm) | Mean 3D distance (mm) | Length (mm) | Soft upper excess (mm) | Max curvature (/m) | Surface z range (mm) |
+|---|---:|---:|---:|---:|---:|---|
+| retained_M18_baseline | 3.230300 | 8.389743 | 585.422575 | 0.422597 | 105.469978 | 7.835153 to 39.086994 |
+| lower_curvature | 3.230262 | 8.390043 | 585.410774 | 0.410795 | 105.489342 | 7.833285 to 39.094202 |
+| stronger_reprojection | 3.093955 | 9.176348 | 585.802734 | 0.802755 | 101.728271 | 6.917458 to 38.935114 |
+
+Lowering curvature weight from 5e-9 to 5e-10 produces effectively unchanged visible geometry and raw residuals under the unchanged solver. It is not evidence that a smaller penalty improves this case.
+
+Doubling reprojection weight improves the mean mask-to-centerline distance in every camera, with small visible contour shifts; pooled point-to-centerline distance and soft-length excess increase. This is a measured tradeoff, not a physical-accuracy result or global winner.
+
+The 2D metric is the equal-view mean visible-mask-pixel distance to the projected centerline; it is not silhouette IoU. The 3D metric is pooled lifted-point distance to the centerline; it is not tube-surface error or ground-truth accuracy. Differently weighted total objectives are not ranked. The results have no new noise or significance bound.
+
+Both candidates follow the exposed narrow chain loop in all four views. The upper grasp remains rounded and hidden closures project across the two hands; camera 12933256 has extensive foreground forearm/sleeve occlusion. This is inferred closed-loop geometry, not a directly measured hidden contour or proof of physical hand penetration.
+
+The two long arcs and grasp closures remain visually very similar across baseline and both candidates. The stronger-reprojection arm has small contour shifts, most visible along the exposed cameras 12540311 and 23007103 arcs; neither arm provides a dramatic visual correction of the hidden shape.
+
+Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse.
+
+The 4.75 mm radius circular tube approximates the linked chain. Ring samples are tube cross-sections, not individual rollers, plates, link gaps or articulation. The object-to-table depth offsets remain uncorrected.
+
+This candidate stops after 1 outer round(s) at `gradient_tolerance`, gradient norm 8.3289618e-05. Soft length and curvature thresholds remain penalties, not hard feasibility limits. Its tube has 144 rings, 1728 vertices and 3456 triangles at 4.75 mm radius; the saved surface-intersection checks pass. Colors are observed for 1094 vertices and median-filled for 634. Hybrid seeds remain 18,412 observed + 103,680 mesh-derived = 122,092; these are appearance seeds, not mechanical particles or mass.
+
+Actual inspection covered 21 panels per candidate: four inputs, four masked centerlines, eight masked/unmasked silhouettes, and scale/depth cloud, depth offset, residual histograms, colors/fill, hybrid populations. Nine orbit samples 0, 4, 8, 13, 17, 21, 26, 30, 35 of 36 at 12 fps were inspected per candidate. The four retained baseline centerline overlays were also inspected. This is bounded sampled viewing, not continuous playback.
+
+Both hands participate: the retained pre-prior reference has 30 controls (14 hand_A, 16 hand_B), selected after the inclusive 4 cm initial gate; maximum initial distance 39.913 mm. Camera 12933256 loses substantial chain support behind the foreground arm. Initial cloud scatter and camera-dependent depth disagreement remain, and missing 3D observations remain NaN. The earlier reference inspection sampled 13 times per view; it does not provide every-frame physical-fitting clearance. [Reference review](<../review_v1/REVIEW.md>). These initial priors do not clear later observations for physical fitting.
+
+[Other candidate](<../prior_review_chain_lower_curvature_v2/PRIOR_REVIEW_c6a_v1.md>) · [Numerical checks](<numeric_prior_review.json>) · [Exact visual findings](<agent_findings.json>).
+
+All six scientific stages and the single explicit-run packager/check returned zero. All 27 reused input payloads match the designated baseline byte-for-byte, and the copied inputs exclude the derived shape GLB. Both designated old M18 baseline fits and manifests remain unchanged. Saved controls and all seven numerical array families are finite; per-view residual quantiles, geometry radius/bounds, vertex colors and hybrid correspondence were checked. Only the assigned new review packets and unique scratch were written; no source, scientific product, global status or owner record was changed.

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_stronger_reprojection_v2/agent_findings.json

@@ -0,0 +1,609 @@
+{
+  "case_id": "233248",
+  "candidate": "stronger_reprojection",
+  "reviewed_utc": "2026-10-28T22:50:57.813107+00:00",
+  "scope": {
+    "goal": "Review both owner-authorized parameter candidates and compare with the retained M18 prior",
+    "done_when": "Per candidate: six science results zero, one package/check,21 actual panels+9 orbit samples, numerical identity/geometry checks and paired findings",
+    "non_goals": [
+      "No science execution or modified scientific products",
+      "No global selection or restoration of revoked acceptances",
+      "No mechanics, trained appearance or physical fitting"
+    ],
+    "validation": "Saved stage results, exact requested settings and unchanged remaining settings, 27 input-byte comparisons, both designated baseline identities, numerical arrays, actual images, and linked packet"
+  },
+  "job": {
+    "case_id": "233248",
+    "session_id": "session_20260921_233248_177244",
+    "case": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747",
+    "prep": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1",
+    "candidate": "stronger_reprojection",
+    "run": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2",
+    "review": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_review_chain_stronger_reprojection_v2",
+    "baseline": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b",
+    "settings": {
+      "control_count": 18,
+      "lambda_curvature_cost": 5e-09,
+      "reprojection_weight": 8.0
+    },
+    "baseline_manifest_sha256": "6bae8ff984f579cef97ccf1543097d97047be94573a7e372c60f6719799e5e7d",
+    "baseline_fit_sha256": "3365dec0010a7eea2936d291f75511051dd6adf4afb8b668de03438306decb30"
+  },
+  "owner_prior_approval": "not accepted; old chain-prior acceptances remain revoked",
+  "full_sequence_physical_fitting_clearance": false,
+  "readiness": "both_candidates_ready_for_owner_comparison_with_preserved_limitations",
+  "inspected_images_relative_to_run": [
+    "review/inputs/view_0_12540311.png",
+    "review/inputs/view_1_12933256.png",
+    "review/inputs/view_2_17736741.png",
+    "review/inputs/view_3_23007103.png",
+    "review/spline/centerline_0_with_masks.png",
+    "review/spline/centerline_1_with_masks.png",
+    "review/spline/centerline_2_with_masks.png",
+    "review/spline/centerline_3_with_masks.png",
+    "review/tube/silhouette_0_unmasked.png",
+    "review/tube/silhouette_1_unmasked.png",
+    "review/tube/silhouette_2_unmasked.png",
+    "review/tube/silhouette_3_unmasked.png",
+    "review/tube/silhouette_0_with_masks.png",
+    "review/tube/silhouette_1_with_masks.png",
+    "review/tube/silhouette_2_with_masks.png",
+    "review/tube/silhouette_3_with_masks.png",
+    "review/tube/tube_scale_views.png",
+    "review/inputs/depth_offset.png",
+    "review/spline/residual_histograms.png",
+    "review/colors/visibility_and_fill.png",
+    "review/hybrid/combined.png"
+  ],
+  "orbit_inspection": {
+    "source": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/tube/orbit.mp4",
+    "reported_frames": 36,
+    "fps": 12.0,
+    "selected_frame_indices": [
+      0,
+      4,
+      8,
+      13,
+      17,
+      21,
+      26,
+      30,
+      35
+    ],
+    "method": "Nine selected direct reads; no continuous playback or full decode claim",
+    "visual_inspection_pending": false,
+    "visual_inspection_complete": true,
+    "observations": "Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse."
+  },
+  "baseline_additional_visual_inspection": [
+    "review/spline/centerline_0_with_masks.png",
+    "review/spline/centerline_1_with_masks.png",
+    "review/spline/centerline_2_with_masks.png",
+    "review/spline/centerline_3_with_masks.png"
+  ],
+  "common_visual_findings": [
+    "Both candidates follow the exposed narrow chain loop in all four views. The upper grasp remains rounded and hidden closures project across the two hands; camera 12933256 has extensive foreground forearm/sleeve occlusion. This is inferred closed-loop geometry, not a directly measured hidden contour or proof of physical hand penetration.",
+    "The two long arcs and grasp closures remain visually very similar across baseline and both candidates. The stronger-reprojection arm has small contour shifts, most visible along the exposed cameras 12540311 and 23007103 arcs; neither arm provides a dramatic visual correction of the hidden shape.",
+    "Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse.",
+    "The 4.75 mm radius circular tube approximates the linked chain. Ring samples are tube cross-sections, not individual rollers, plates, link gaps or articulation. The object-to-table depth offsets remain uncorrected."
+  ],
+  "candidate_interpretation": "Doubling reprojection weight improves the mean mask-to-centerline distance in every camera, with small visible contour shifts; pooled point-to-centerline distance and soft-length excess increase. This is a measured tradeoff, not a physical-accuracy result or global winner.",
+  "paired_metrics": [
+    {
+      "label": "retained_M18_baseline",
+      "run": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/chain_centerline_comparison_v1/variant_b",
+      "control_count": 18,
+      "lambda_curvature_cost": 5e-09,
+      "reprojection_weight": 4.0,
+      "rounds": 1,
+      "stop": "gradient_tolerance",
+      "grad_norm": 6.256708002183586e-05,
+      "length_mm": 585.4225754737854,
+      "soft_length_excess_mm": 0.42259693145751953,
+      "max_curvature_per_m": 105.46997833251953,
+      "mean_3d_point_to_centerline_mm": 8.389742558768171,
+      "mean_2d_mask_to_centerline_mm": 3.230299700766787,
+      "surface_z_min_max_mm": [
+        7.835153490304947,
+        39.08699378371239
+      ],
+      "observed_filled_vertices": [
+        1089,
+        639
+      ],
+      "reprojection_per_view": [
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+          "serial": "12540311",
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+          "median_depth_m": 1.116,
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+          "visible_centerline_samples": 306,
+          "outside_mask_fraction": 0.00980392156862745
+        },
+        {
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+          "outside_mask_fraction": 0.051094890510948905
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+          "at_cap_fraction": 0.0
+        }
+      ],
+      "geometry_passed": true
+    },
+    {
+      "label": "lower_curvature",
+      "run": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_lower_curvature_v2",
+      "control_count": 18,
+      "lambda_curvature_cost": 5e-10,
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+      "geometry_passed": true,
+      "delta_from_baseline": {
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+        "max_curvature_per_m": 0.0193634033203125,
+        "mean_3d_point_to_centerline_mm": 0.0002999693076066734,
+        "mean_2d_mask_to_centerline_mm": -3.7793919371420515e-05
+      }
+    },
+    {
+      "label": "stronger_reprojection",
+      "run": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2",
+      "control_count": 18,
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+  ],
+  "comparison_rule": "Common raw diagnostics and visual evidence; differently weighted total objectives are not ranked. No noise/significance bound is inferred.",
+  "temporal_and_hand_context": "Both hands participate: the retained pre-prior reference has 30 controls (14 hand_A, 16 hand_B), selected after the inclusive 4 cm initial gate; maximum initial distance 39.913 mm. Camera 12933256 loses substantial chain support behind the foreground arm. Initial cloud scatter and camera-dependent depth disagreement remain, and missing 3D observations remain NaN. The earlier reference inspection sampled 13 times per view; it does not provide every-frame physical-fitting clearance.",
+  "reference_review_record": {
+    "case": "233248",
+    "window_anchor_inclusive": [
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+    "reviewer": "chain preparation agent",
+    "reviewed_utc": "2026-10-28T13:08:53.813975+00:00",
+    "coverage": {
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+          "17736741",
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+        "support_and_rejections (all four cameras)",
+        "paired_native_WAFT_depth (all four cameras)",
+        "derived_coverage"
+      ],
+      "derived_geometry": [
+        "object_and_hand_xy.png",
+        "source_center_graph.png"
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+    },
+    "observations": [
+      "At all 13 sampled times in each of four views, admitted object support follows the visible chain and hand support follows the physical right and left hands; no broad background drift or hand-identity swap is visible.",
+      "Object support remains nonzero in every native view throughout the selected span. Camera 12933256 has substantially less support during foreground-arm occlusion (55\u2013248 admitted native object points); hidden and rejected predictions remain separate from measurements.",
+      "All 30 selected controls remain valid at every derived sample: 14 hand_A and 16 hand_B. The global FPS population was selected after the unchanged inclusive 4 cm initial gate; maximum selected distance is 39.91314803066454 mm. No hand quota was imposed.",
+      "The 541-sample exact 30 Hz derived bundle retains 707 mesh-free object representatives with 430\u2013707 visible per sample. Initial, middle and final XY views preserve the chain configuration; the initial cloud has measurable scatter. No isolated object node or unattached control is reported in the source-center graph.",
+      "Native-versus-WAFT depth differences vary by camera and time. These are paired same-pixel diagnostics, not depth truth; no depth replacement, gap filling, point movement or threshold change was applied."
+    ],
+    "array_checks": {
+      "raw_queries_and_native_times_unchanged": true,
+      "raw_TAP_coordinates_logits_certainty_finite": true,
+      "lifted_valid_samples_finite": true,
+      "missing_3d_samples_remain_NaN": true,
+      "all_role_and_human_masks_covered": true,
+      "selected_controls_all_time_valid": true,
+      "participating_hands": [
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+      "selected_controls_per_hand": {
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+        "hand_B": 16
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+      "controller_initial_distance_m_max": 0.03991314803066454,
+      "initial_object_xyz_m_min_max": [
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+        [
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+          0.023481816239153824,
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+      ],
+      "unit_masses_and_model_arrays_equal_saved_observations": true
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+    "initialization": {
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+      "controls": 30,
+      "total_source_mass_units": 707.0,
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+        "isolated_object_nodes": 0,
+        "attached_object_nodes": 148,
+        "controls_without_attachment": 0,
+        "attachments_by_hand": {
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+      }
+    },
+    "interpretation": "No material blocker found to preparing the requested current-C2 bike-chain prior from these accepted inputs. This is agent inspection, not owner acceptance of a future prior or appearance. The mesh-free node count is pre-prior inspection, not final mechanics.",
+    "limitations": [
+      "Visual review sampled 13 times per view, not every video frame.",
+      "Tracker visibility and certainty are not geometric accuracy.",
+      "Initial lifted scatter and multiview depth differences remain; the requested prior geometry, silhouette/depth diagnostics and owner review are still required."
+    ],
+    "full_window_media": {
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+    },
+    "science_parameters_changed": false,
+    "prior_fit_run_by_this_agent": false
+  },
+  "numeric_review": "numeric_prior_review.json",
+  "scientific_outputs_modified": false,
+  "source_code_modified": false,
+  "global_or_owner_records_modified": false,
+  "blocking_review_completion_findings": []
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_stronger_reprojection_v2/numeric_prior_review.json

@@ -0,0 +1,833 @@
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+    "review/tube/silhouette_0_with_masks.png",
+    "review/tube/silhouette_1_with_masks.png",
+    "review/tube/silhouette_2_with_masks.png",
+    "review/tube/silhouette_3_with_masks.png",
+    "review/tube/tube_scale_views.png",
+    "review/inputs/depth_offset.png",
+    "review/spline/residual_histograms.png",
+    "review/colors/visibility_and_fill.png",
+    "review/hybrid/combined.png"
+  ],
+  "owner_prior_approval": "not accepted; all old chain-prior acceptances revoked"
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_stronger_reprojection_v2/orbit_frames.json

@@ -0,0 +1,20 @@
+{
+  "source": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/tube/orbit.mp4",
+  "reported_frames": 36,
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+  "method": "Nine selected direct reads; no continuous playback or full decode claim",
+  "visual_inspection_pending": false,
+  "visual_inspection_complete": true,
+  "observations": "Scale/depth and hybrid panels retain multiview thickness/scatter around the tube and sparse points away from the main loop. Colors are median-filled on underside and occluded ends. Both orbit samples show a closed continuous loop with smooth height variation and no gross crossing, detached segment, seam opening or local tube collapse."
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_chain_stronger_reprojection_v2/prior_metrics.json

@@ -0,0 +1,436 @@
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+      "components": 1,
+      "winding_consistent": true,
+      "signed_volume_m3": 3.960460143333692e-05,
+      "minimum_outward_normal_dot_m": 0.004527152390372858,
+      "degenerate_triangles": 0,
+      "self_intersecting": false,
+      "maximum_radius_error_m": 5.648259342010131e-09,
+      "maximum_diameter_error_m": 1.1296518684020262e-08,
+      "bishop_seam_error": 0.0,
+      "minimum_nonadjacent_centerline_distance_m": 0.006382872557954916,
+      "triangle_area_m2": {
+        "min": 2.1176254238759276e-06,
+        "median": 4.8473150735978055e-06,
+        "mean": 4.99761933191097e-06,
+        "max": 6.882422474374204e-06,
+        "density_max_over_min": 3.2500660394307053
+      },
+      "bounds_m": [
+        [
+          -0.02584436908364296,
+          -0.24476440250873566,
+          0.006917458027601242
+        ],
+        [
+          0.10132459551095963,
+          0.007686873897910118,
+          0.038935113698244095
+        ]
+      ],
+      "radius_m": 0.00475,
+      "step_t": 0.125,
+      "step_angle_deg": 30,
+      "overlap_rule": "surface_intersection",
+      "open3d_reported_intersecting_pairs": 0,
+      "confirmed_intersecting_pairs": [],
+      "passed": true,
+      "orientation_flipped": true
+    }
+  },
+  "appearance_seed_counts": {
+    "observed": 18412,
+    "mesh": 103680,
+    "total": 122092,
+    "mesh_to_observed": 5.631110145557245
+  },
+  "vertex_colors": {
+    "observed_vertices": 1094,
+    "filled_vertices": 634
+  },
+  "mechanical_population": {
+    "particle_count": null,
+    "total_unit_mass": null,
+    "status": "not produced by the prior run; no post-prior mechanics are evaluated here"
+  },
+  "source_code": {
+    "commit": "98ebffe13629edeb0a9b29df973bebc5730d7026",
+    "u_pin": "81c718790a37e5e0102eb77af2c6edd34a9db25f"
+  },
+  "media": {
+    "full_rotation": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/tube/orbit.mp4",
+    "geometry_depth_cloud": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/tube/tube_scale_views.png",
+    "depth_offset_diagnostic": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/inputs/depth_offset.png",
+    "residual_histograms": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/spline/residual_histograms.png",
+    "color_visibility_fill": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/colors/visibility_and_fill.png",
+    "hybrid_seed_populations": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/review/hybrid/combined.png",
+    "derived_coverage": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/derived/derived_coverage.png"
+  },
+  "sources": {
+    "manifest": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/manifest.json",
+    "fit": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/steps/fit.json",
+    "geometry_checks": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/tube/tube_checks.json",
+    "reference_views": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/inputs/reference_views.json",
+    "reprojection": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_stronger_reprojection_v2/spline/reprojection.json",
+    "tracking_summary": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/review_v1/summary.json",
+    "frames": "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/frames_waft.npz"
+  }
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_result.json

@@ -0,0 +1,4 @@
+{
+  "returncode": 0,
+  "elapsed_s": 12.59115836800629
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_v1/agent_findings.json

@@ -0,0 +1,67 @@
+{
+  "status": "current C2 prior completed and reviewed; owner prior acceptance pending",
+  "identity": {
+    "prior_manifest_sha256": "8a2748dd8555f95fd651c2cb13800ecde5b7d1c13f21dc1a0b9947a6b6d08533",
+    "mesh_sha256": "2c9722285018e8835442f04348063ace8cb2c110da1800d7feac39ce794a2c3c"
+  },
+  "visually_inspected_prior_files": [
+    "review/tube/silhouette_0_unmasked.png",
+    "review/tube/silhouette_1_unmasked.png",
+    "review/tube/silhouette_2_unmasked.png",
+    "review/tube/silhouette_3_unmasked.png",
+    "review/spline/centerline_0_with_masks.png",
+    "review/spline/centerline_1_with_masks.png",
+    "review/spline/centerline_2_with_masks.png",
+    "review/spline/centerline_3_with_masks.png",
+    "review/tube/tube_scale_views.png",
+    "review/colors/visibility_and_fill.png",
+    "review/spline/fit_3d.png",
+    "review/spline/residual_histograms.png",
+    "review/hybrid/combined.png"
+  ],
+  "orbit_frames_inspected": [
+    0,
+    5,
+    10,
+    15,
+    20,
+    25,
+    30,
+    35
+  ],
+  "orbit_frame_count": 36,
+  "observations": [
+    "The tube/centerline follows the visible chain in all four views and preserves its elongated noncircular shape and bends.",
+    "The closed spline continues under the two hands; those sections are inferred and camera12933256 has substantial occlusion.",
+    "A continuous4.75mm-radius tube approximates the chain, without link-resolved geometry.",
+    "The depth clouds have view-dependent vertical/lateral spread; the spline has not been flattened or shifted to the table.",
+    "No confirmed surface self-intersection; minimum nonadjacent ring-centre distance is diagnostic only under approved Q8."
+  ],
+  "measurements": {
+    "arclength_m": 0.5853944420814514,
+    "arclength_soft_upper_bound_exceedance_m": 0.00039444208145145154,
+    "max_curvature_per_m": 92.25138854980469,
+    "gradient_norm": 8.69055584189482e-05,
+    "rounds": 2,
+    "tube_min_z_m": 0.0068970248103141785,
+    "per_view_median_centerline_residual_m": [
+      0.008376180194318295,
+      0.005763906287029386,
+      0.0064223394729197025,
+      0.010788764338940382
+    ],
+    "visible_centerline_inside_mask_fraction": [
+      0.9636363636363636,
+      0.9407407407407408,
+      0.9622641509433962,
+      0.984472049689441
+    ],
+    "hybrid_counts": {
+      "observed": 18412,
+      "mesh": 51840,
+      "total": 70252,
+      "mesh_to_observed": 2.8155550727786225
+    }
+  },
+  "interpretation": "Ready for separate owner prior review. Geometry checks and image agreement do not establish physical accuracy or accepted appearance. No mechanical population or trained appearance is claimed for this case."
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_review_v1/source_frame_mapping.json

@@ -0,0 +1,34 @@
+[
+  {
+    "serial": "12540311",
+    "selected_window_local_index": 0,
+    "converted_frame": 208,
+    "native_container_frame": 209,
+    "capture_timestamp_ns": 1790047997824416092,
+    "initial_grid_offset_ms": 15.329769
+  },
+  {
+    "serial": "12933256",
+    "selected_window_local_index": 1,
+    "converted_frame": 208,
+    "native_container_frame": 209,
+    "capture_timestamp_ns": 1790047997855459906,
+    "initial_grid_offset_ms": -15.714045
+  },
+  {
+    "serial": "17736741",
+    "selected_window_local_index": 0,
+    "converted_frame": 208,
+    "native_container_frame": 209,
+    "capture_timestamp_ns": 1790047997839745861,
+    "initial_grid_offset_ms": 0.0
+  },
+  {
+    "serial": "23007103",
+    "selected_window_local_index": 0,
+    "converted_frame": 208,
+    "native_container_frame": 209,
+    "capture_timestamp_ns": 1790047997829389080,
+    "initial_grid_offset_ms": 10.356781
+  }
+]

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_tube.log

@@ -0,0 +1 @@
+tube: ok -> /mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_v1/steps/tube.json

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_tube_argv.json

@@ -0,0 +1,12 @@
+{
+  "argv": [
+    "/mnt/data0/magna/belt_perception_wt_c6a_lab_input_preparation_20261027/.venv/bin/python",
+    "scripts/real_rgbd_appearance_spline_prior.py",
+    "tube",
+    "--run",
+    "/mnt/data2/magna/belt_perception_shared/phystwin_model_corpus_expansion/lab/session_20260921_233248_177244/window_anchor0208-0747/accepted_input_preparation_c6a_v1/prior_chain_v1"
+  ],
+  "environment": {
+    "JAX_PLATFORMS": "cpu"
+  }
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/prior_tube_result.json

@@ -0,0 +1,4 @@
+{
+  "returncode": 0,
+  "elapsed_s": 5.032006531997467
+}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/query_tracks.log

@@ -0,0 +1,8 @@
+12540311: tracked 5000 queries
+12933256: tracked 5000 queries
+17736741: tracked 5000 queries
+23007103: tracked 5000 queries
+12540311: members {'object': 755, 'hand_A': 2511, 'hand_B': 1687}
+12933256: members {'object': 364, 'hand_A': 2008, 'hand_B': 2509}
+17736741: members {'object': 731, 'hand_A': 2459, 'hand_B': 1698}
+23007103: members {'object': 816, 'hand_A': 1417, 'hand_B': 2638}

sessions/session_20260921_233248_177244/preprocessing/chain-stronger-reprojection-v2/native/query_tracks/lifted_12540311.npz

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