How to read IfcPropertySingleValue from an IFC file?

The property set information is stored on the IFC feature geometry as traits, rather than as feature attributes. The IFC feature geometry will be an aggregate of Body and Annotation geometries, plus Null geometries for each PropertySet, with the Property Set values stored as traits on the Property Set geometry. You can convert these traits to attributes using the GeometryPropertyExtractor transformer.

However, it would be simpler to use the FME Revit reader, which can read IFC files as well, and has Data Views that automatically simplify the complex IFC data structure for you. The default Building Elements with hierarchy data view should produce PostGIS compatible features.

Thank you @DaveAtSafe. Unfortunately, I don't have access to the full version of Revit, which seems to be necessary to be able to use the FME Revit exporter, which can produce the files the FME Revit reader works with.

I have tried the GeometryPropertyExtractor, but I do not notice an effect when I add it to the translation. The output is the same with or without the transformer. Should the GeometryPropertyExtractor somehow read the available traits from the IFC data source, giving me the option to map them to an output database column?

I do see that the geometries are aggregates of empty geometries and non-empty geometries. Should the input geometry perhaps be deaggregated and the empty geometries be isolated first? Could something like that make the traits (PropertySet values) visible in the workbench?

By the way, I am rather new to FME, so there might be obvious things I am missing.

Hello @DaveAtSafe. Thanks again for the advice. It is good to know it is possible to use the Revit reader on plain IFC files. It gave me more feature types and more direct access to data, but the data I would like to transform still were not available as attributes of the BuildingElementProxy feature type. The values I am looking for are in the PropertySet 'Identity Data'. The reader does make values from that PropertySet available, but not the values I would like to transform. Is there a way to expose additional feature attributes in the Revit reader?

About the tip about data views: I looked in the FME\\datasources directory and all I can see is *.fds files. Those are custom format files, right?

Hello,

I have a similiar question. I'm trying to convert IFC files to Excel. What I'm after is the IfcClass + Pset + Attribute + Value combination, so the GeometryPropertyExtractor is perfect. That's part 1, solved.

Now, part 2:

How would I go about exposing ALL of the attributes the PropertyExtractor found dynamicly? I know there is an AttributeExploder, that kind of does that but it creates two columns (name, value) which is not quite what I'm after. I would have to do some kind of transpose, or crosstab operation on those. Not so great...

Is there no out of the box solution for "simply" exposing all attributes at once?

Hi @ras,

To expose the attributes ot the workspace, you need to manually do so in the AtttributeExposer.

However, if you want them automatically added to the Excel output, you can create a schema feature from data and use that with a dynamic schema in the output Excel feature type. The SchemaSetter transformer will create a schema for you.