Hello FME-Communtiy,
With the advent of the new IFC-Writer we wanted to update and hopefully slim down our FME Workspace, which reads Multipatch Geometries via an Esri Geodatabase (File Geodb) Reader and writes IFC-Features via an IFC XML/STEP (deprecated) writer. Sadly we’ve not managed to get the new writer working as needed and have found the documentation rather lackluster, which is why I’d appreciate any pointers from the knowledgeable people on here.
The new workspace has managed to correctly export the feature geometries, but the attributes seem to be missing/not written at all. Inside the new Workspace the features have the correct attributes and values up until the very end where they are sent to the IFC-writer (In this Case I tried Slab as the Element Type, BuildingElementProxy gave the same results and SpatialZone doesn’t work at all anymore).
In the old Workspace there were 4 IFC-Writer-Feature Types (if thats the correct terminology to use) called IfcProject, IfcSite, PropertySetDefinition and IfcSpatialZone. When running the workspace Building and BuildingStorey elements are automatically created and the SpatialZone-Features were automatically attached to the BuildingStorey.
The old workspace uses an IFCPropertySetDefinitionCreator Transformer to create all of the PropertySets (extremely tedious because of the high amount of attributes that need to be manually entered). According to the FME Documentation you should now be able to avoid this manual PropertySet-Definition by simply using the naming convention SetName.PropertyName. My question here is if this is only true when modifying already existing IFC-Files like in this exercise and if you do have to write a PropertySetDefinition when creating IFC-Files from the ground up.
Another issue is the hierarchy of written objects. In the old workflow, the SpatialZones were automatically attached to BuildingStorey, which was nested within Building and so on (viewed in BIMvision).
In the new workflow, both the IfcSite and IfcBuilding objects seem to be attached to IfcProject, even when manually trying to force the correct hierarchy (Site > Building > BuildingStorey > actual features) by writing ifc_global_id / ifc_parent_id attribute values (they get overwritten by the IFC writer for some reason). Most importantly the actual features (Slab/BuildingElementProxy) are completely missing.
Is there some specific way you need to write the Project / Site / Building / BuildingStorey features to ensure that the main objects can “attach” to them?
I hope I’ve managed to describe my problems somewhat sensibly and would be happy about some feedback/tips!