{
  "schema": "midget-manifold-face-survey-v1",
  "units": "mm",
  "method": null,
  "basis": null,
  "joint": "fan_to_coupling",
  "surveyed_component": null,
  "component_identity_observation": null,
  "photo_refs": [],
  "frame": {
    "name": null,
    "origin_datum": null,
    "x_positive": null,
    "y_positive": null,
    "z_positive": null,
    "configuration": null,
    "right_handed_orthonormal": null
  },
  "survey": {
    "same_component_face_and_configuration_confirmed": null,
    "joint_face_datum_note": null,
    "positive_normal_direction_note": null,
    "first_three_face_points_define_positive_normal_confirmed": null,
    "face_points": [
      {
        "name": "P1",
        "xyz_mm": [
          null,
          null,
          null
        ],
        "datum_note": null
      },
      {
        "name": "P2",
        "xyz_mm": [
          null,
          null,
          null
        ],
        "datum_note": null
      },
      {
        "name": "P3",
        "xyz_mm": [
          null,
          null,
          null
        ],
        "datum_note": null
      },
      {
        "name": "P4 independent plane check",
        "xyz_mm": [
          null,
          null,
          null
        ],
        "datum_note": null
      }
    ],
    "boundaries": [
      {
        "name": null,
        "role": null,
        "observation_note": null,
        "ordered_closed_joint_face_trace_confirmed": null,
        "points": [
          {
            "name": "opening-1/A",
            "xyz_mm": [
              null,
              null,
              null
            ],
            "datum_note": null
          },
          {
            "name": "opening-1/B",
            "xyz_mm": [
              null,
              null,
              null
            ],
            "datum_note": null
          },
          {
            "name": "opening-1/C",
            "xyz_mm": [
              null,
              null,
              null
            ],
            "datum_note": null
          },
          {
            "name": "opening-1/D",
            "xyz_mm": [
              null,
              null,
              null
            ],
            "datum_note": null
          }
        ],
        "independent_chord_distances": [
          {
            "from": "opening-1/A",
            "to": "opening-1/B",
            "distance_mm": null,
            "measurement_point_and_method_note": null
          },
          {
            "from": "opening-1/A",
            "to": "opening-1/D",
            "distance_mm": null,
            "measurement_point_and_method_note": null
          }
        ]
      }
    ]
  },
  "limits": "Blank direct survey for one actual fan or fan_coupling bearing face. Select surveyed_component only after identifying the physical part. Keep each pad and face independently identified and tied to its original numbered photograph; do not infer four coplanar pads, a circular hole, pad thickness or fitted pose. Use fixing_hole or face_outer_edge for directly observed closed traces. Add boundary records only for actual observed outlines. All coordinates, source notes, frame declarations and comparison limits require direct evidence; null values are unknown. The existing manifold-named schemas and tools also support this joint. Separate surveys and independent registration are needed for the other mating part or opposite face. Output is sample chords/check vertices only, never a solid, engine update, inferred thickness, fit, clamp force, clearance or removal path."
}