This follows up on the closed thread Omniverse -open USD meets Open BIM When?, where it was noted that connectors often flatten BIM semantics and that IFC property sets are only partially available once the model is in USD.
Workflow
- An air-handling unit modeled in Revit, exported to IFC with all property-set options enabled
- Converted to OpenUSD with our own converter (PM AutoTwin Studio from PocketMemory; its OpenUSD export is in beta)
- Opened in USD Composer and compared against the source IFC
Result
Properties such as voltage, volume, pressure drop and part IDs matched the source values.
Scope and limits
- One asset, checked manually in USD Composer
- IFC to USD only, no round trip
- The mapping of IFC property sets onto USD prims is our own implementation, not a standard
- Environment: USD Composer
Questions
- Is there a recommended convention for carrying IFC property sets in USD, for example custom attributes on the prims versus a separate metadata layer?
- How are you checking that properties survive conversion today? We compare by GlobalId against the source IFC, but we would like to know what others do.
Happy to share the method in more detail if it is useful.