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ReconstructionPASS 12/12

NIST AMB2022-01 bridge, mesh reference

The same bridge artifact, checked against a reference mesh for surface deviation.

Facts

Backend
FreeCAD
Gates
12 pass, 0 fail, 0 n/a
Bounding box
75.0 × 5.0 × 12.5 mm
Volume
3.68 cm³
Process
Laser powder bed fusion (LPBF); nominal individual as-built geometry before EDM separation or tab skim cutting
Release
reconstruction

Source

contract.yaml (design contract)

Design intent

Reconstruct the NIST AMB2022-01 individual bridge artifact as editable, parameterized KCL from the attached NIST description excerpts and figures; Figure 3 is the dimensioned plan and elevation drawing and is authoritative for every external dimension. Frame: x along the 75 mm length with x = 0 at the pointed (45 degree tapered) end and x increasing toward the far end, y across the 5 mm width with y = 0 at one long side face, z vertical from the build plate (z = 0) upward. Model the tapered nose, the tall solid end block, the twelve legs with their 45 degree overhangs merging into the solid bridge, the eleven 1 mm wide top tabs on a 7 mm pitch, and the hollow leg L10 with its 0.5 mm outer walls, 1 mm base, four 4 mm tall internal thin walls parallel to x, and flat ceiling, exactly as documented. Where the sources do not fix a dimension (the single- and double-track thin-wall widths), record it as an open question and use a clearly labelled inferred value with a wide tolerance rather than approximating silently. One solid; export STEP and STL. Reference geometry supplied by NIST is for inspection only: the deliverable must be editable construction, never an import.

Gates

TierGateResultEvidence
Acontract_provenance
Contract validates; stated/measured sources resolve to bundle files; no blocking open questions; interfaces pinned by checks
PASSdesigns/nist-amb2022-01-bridge-mesh/contract.yaml: 36 parameters {'stated': 12, 'derived': 11, 'measured': 11, 'inferred': 2}; sources unresolved {}; unanchored 0
Aenvelope
Bounding box of the exported STEP equals the contract envelope
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json bbox.max_error = 0.0 (tol 0.1)
Amass_properties
Volume, surface area and centre of mass within contract tolerance (independent STEP measurement)
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json volume = 3678.1 vs 3678.1
Afeatures
Every required feature, section, named face, cylinder axis, plane, dimension, body, clearance, passage, wall, gear and symmetry check verified on the STEP
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json features: 11/11 ok; failed required []; failed optional []; unverified []
Areference_fidelity
Deviation from the reference model within the contract band (when a reference exists)
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json deviation.p95 = 4.890466160466869e-13 hausdorff = 0.17910003662109375 silhouette_iou_min = 1.0
Bexport_agreement
Engine, STEP (OpenCascade) and STL (trimesh) volumes agree
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json agreement engine=3678.099999999999 step=3678.100000000001 stl=3678.100000381468 (rel tol 0.002; independent=False)
Bedit_robustness
Declared parameter edits rebuild with the expected effect, undriven interfaces stay put, sweeps regenerate, infeasible values are refused; baseline re-export hash unchanged
PASSresults/freecad/nist-amb2022-01-bridge-mesh/edit.json 3/3 edit tests ok; restore.ok = True
Bsource_hygiene
Dialect, units, formatted, lint-clean, named parameters match the contract, asserts present
PASSresults/freecad/nist-amb2022-01-bridge-mesh/verify.json hygiene: dialect=True unit=True legacy=[] params_ok=True asserts=63
Cexport_integrity
Deterministic STEP (two exports identical), valid B-rep, expected solid count, watertight STL (solid shells == solids)
PASSresults/freecad/nist-amb2022-01-bridge-mesh/export.json step.deterministic = True sha256 61ceb8f37c67; stl=present; glb=present
Ctraceability
Every stage JSON present with tool versions, git head, worker thread ids, engine-call ledger; no --allow-errors
PASSstages present: {'plan': True, 'model': True, 'verify': True, 'export': True, 'inspect': True, 'edit': True}
Cevidence_separation
Contract agreement, reference agreement and physical validation are reported as separate verdicts
PASSresults/freecad/nist-amb2022-01-bridge-mesh/inspect.json carries contract checks (volume/bbox/features) and a separate deviation block (reference = /Users/danieldriscoll/dual/skillkat/designs/nist-amb2022-01-bridge-mesh/reference/reference.ply)
Cindependence
The source is editable construction: no import of reference geometry, construction ops present
PASSresults/freecad/nist-amb2022-01-bridge-mesh/verify.json hygiene.forbidden_imports = [] construction_ops = {'calls': 13, 'has_result': True} lines = 267