IFC type for Light Fixture

[Matthew Johnson]

In building a custom translator for IFC publishing I would like to be able to export only the lights from a project to an IFC file. (reason being that I'm building a coordination model that is assembled in Tekla's BIMsight from sub-discipline models and we had to build the electrical model for the electrical engineer)

Unfortunately even though ArchiCAD allows us to tag an object with an Element Classification of "Light Fixture" there is no mapped IfcName that can be filtered in the IFC export settings.

Light Fixture = IfcFlowTerminal

but so does...

Pipe Terminal (MEP) = IfcFlowTerminal
Duct Terminal (MEP) = IfcFlowTerminal

...so all of my taps and HVAC registers would be exported as well.

Why does ArchiCAD provide a Element Classification that does not map to an IfcName?

[Anonymous]

Hi Matthew,

This is one of the areas improved on for IFC4. There is a class specifically for light fixtures, http://www.buildingsmart-tech.org/ifc/IFC4/final/html/link/ifclightfixture.htm

In IFC2x3, the flow terminal class was used for the instance, but a specific type could assign purpose IfcLightFixtureType http://www.buildingsmart-tech.org/ifc/IFC4/final/html/link/ifclightfixturetype.htm Or of course other terminals as you have recognized.

I don't know Archicad well enough to know if the user can define this in the settings for export. Hopefully someone else can advise.

Cheers,

Jon

[Laszlo Nagy]

Matthew,

I assume you know that you can select elements in the Floor Plan or in 3D and save as IFC only those.
Also, you can save as IFC only visible Layers.

[Matthew Johnson]

Lazlo,

I realise I could use the selected elements or by visible layer methods for saving out the files but what I am trying to set up is a structured publishing set of IFC sub models by discipline.

This would then enable us to publish part models of our shopping mall projects and issue smaller byDiscipline/byTrade IFC models to the consultant team that can then be reassembled in Tekla BIMsight or Revit or whatever. Similar to the "delta technology" BIM Server uses this would mean that if we changed a steel column setout in our ArchiCAD model we only have to re-issue the "IFC - Structural - Steel" model rather than the entire 200Mb+ whole of building IFC which takes ages to export then re-import to Revit etc.

I'd prefer not to have to create a "lights" layer and a "power outlet" layer and a "switchboard" layer and so on.

[Laszlo Nagy]

The layer solution is the only one I can suggest for this situation.
If anyone knows anything better, please chime in.