Questions about IFC_subtype and IFC_predefinedtype ??

[Nader Belal]

Hi there,

Long story short, IFC_subtype & IFC_predefinedtype are two Graphisoft's standard predefined integer parameters ArchiCAD's the IFC add-on (textually extracted from the GDL Reference Guide)

In the manuals the IFC_subtype values are defined within the guides, but there is nothing about IFC_predefinedtype although they're standard paramater in MEP GDL subtype (haven't checked them all).

Does anyone have IFC_predefinedtype values definition ??

[Nader Belal]

Ok, I contacted @Mario Saco and advised me to consult ArchiCAD Standard Library ... (Good call )

Which I did, and I (to Graphisoft team - correct me if I´m wrong), I found correlation between ifc_predefinedtype and the index of the enumerated subtype.

So please Graphisoft team ... confirm if my assumption is true !!

And if that was the case, please revise all ArchiCAD Standard MEP objects that have "Balancing Dumper" in its name, sine in its GDL script the pre_definedtype = 11, while in the IFC schema for the IfcDamperTypeEnum it's in the 10th position .

[Nader Belal]

Graphisoft,

If my assumption is true, please do revise the IFC_predefinedtype values for your MEP library Grills

[Nader Belal · Accepted solution]

Ok, I´m writing this to give newcomers of GDL the chance to find the answer to this question in an easier manner.

Based on @Akos recommendations in the following thread (https://archicad-talk.graphisoft.com/viewtopic.php?f=23&t=68849) , I got this answer.

Péter Baksa wrote:

I got some clarification from the developers:

An IFC translator has a "Type Mapping" preset, where a classification-based or element-based rule set can be defined. In the template shipped with AC, the classification system "ARCHICAD Classification" is set up to work with the IFC translators, always defining an IFC type and Predefined Type. Using these translators, IFC_predefinedtype has no effect.

When an IFC translator is set up to use element mapping, the mapping is not customizable by the user, and depends on the AC version. For AC23 this document shows two MEP element types where IFC_predefinedtype is handled by the translator. On the AC side, these parameters are handled by the MEP add-on.

So IFC_predefinedtype is retired, it exists in GDL elements only for compatibility.

Source: http://gdl.graphisoft.com/forums/topic/questions-about-ifc_predefinedtype-gdl-parameters/#post-18588