The bare IfcGUID behind an adapter key, or empty when the key is not one.
The STEP adapter keys an element on its GlobalId, suffixed with
:<occurrence> for a GPU-instanced occurrence, and falls back to
expressid:<model>:<n> when the entity has no GlobalId; the IFCX adapter
keys on a USD prim path. Only the first form is a GUID a reader can join on,
so the others yield an empty cell rather than a string that LOOKS joinable.
Validity is the encoder's own rule (isValidIfcGuid: 22 chars of the IFC
base-64 alphabet whose first character encodes only 2 bits, so 0–3) —
a malformed file's Z000… GlobalId is kept as the run's key but is not
offered as a GUID.
The bare IfcGUID behind an adapter key, or empty when the key is not one.
The STEP adapter keys an element on its GlobalId, suffixed with
:<occurrence>for a GPU-instanced occurrence, and falls back toexpressid:<model>:<n>when the entity has no GlobalId; the IFCX adapter keys on a USD prim path. Only the first form is a GUID a reader can join on, so the others yield an empty cell rather than a string that LOOKS joinable. Validity is the encoder's own rule (isValidIfcGuid: 22 chars of the IFC base-64 alphabet whose first character encodes only 2 bits, so0–3) — a malformed file'sZ000…GlobalId is kept as the run's key but is not offered as a GUID.