RE-23 (#226) established that every Revit 2024 element record carries a counted u64 reference list at +0x88 (length 6 on doors, 18 on windows, up to 101 elsewhere) and that the host wall is the slot before the record's own ElementId. The other slots are recorded, not decoded: a leading 3, and ids that look like family, type and level references (trailing type-symbol slots on 81 door records are RE-21 symbol envelopes). Attribute them with the set-difference method against the export (IfcRelDefinesByType, IfcRelContainedInSpatialStructure) — a level slot that reproduces the export's storey containment exactly would be a direct binding source (see #218/#219); keep #86 (Level ElementIds on magnetar) as the research wall it is unless the join is exact.
RE-23 (#226) established that every Revit 2024 element record carries a counted u64 reference list at +0x88 (length 6 on doors, 18 on windows, up to 101 elsewhere) and that the host wall is the slot before the record's own ElementId. The other slots are recorded, not decoded: a leading 3, and ids that look like family, type and level references (trailing type-symbol slots on 81 door records are RE-21 symbol envelopes). Attribute them with the set-difference method against the export (IfcRelDefinesByType, IfcRelContainedInSpatialStructure) — a level slot that reproduces the export's storey containment exactly would be a direct binding source (see #218/#219); keep #86 (Level ElementIds on magnetar) as the research wall it is unless the join is exact.