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Standard XML for IFC Clasifications

Hello All

I need to know if there is any standard for xml focused in classifications in IFC (ifcClassificationReference)

ArchiCAD creates and export an xml for clasifications created inside.
USBIM viewer can include the archicad xml exported
AECOSIM can’t althouth it has a folder with xml clasiffications… you have to re-create the same classification xml with other script based on xml.

I would prefer if the standard for classifications in xml has been approved by BuildingSmart because i’ve been talking about this topic with different BIM software developers.

Thank you in advance

It’s an interesting topic. I’d advocate for using the IFC data model to publish classifications and property templates. Here’s an example of publishing uniclass2015 to STEP and ifcXML

Uniclass2015.ifcxml (1.7 MB)
Uniclass2015.ifczip (191.7 KB)

It would be interesting to hear any further attributes you’d like included in IFC that exist in the ARCHICAD xml.

I’ve been prototyping some tools to generate the ARCHICAD xml (including nominating a filter on the classification such as only products from uniclass2015 or Architectural domain in IFC). I’d certainly also consider a tool to generate AECOSIM folder definition.

I look forward to discussing further,


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Thanks Jon, just wanted to inform you that those Uniclass files don’t have “Role - Ro” section because Uniclass shared Roles recently

Also, it’s good to update classifications like Uniclass and other classifications with new ISO BIM standard (ISO 19650) which Uniclass included it in its platform but needs some improvements

Also update classifications based on IFCX (IFC2X3 and IFC4, …)

Can you share ARCHICAD xml file or link?

Sure, these files are from a few versions back of uniclass2015. I can look at updating it, but I have suggested to NBS that they might provide the classification in this format themselves.

I don’t know if ARCHICAD publish an xsd for their classification and property templates but it’s fairly easily recognized from exporting from the App. I will look at providing tools for this ASAP if there is interest for it.

Thank you Jonm.

What i really need is a Classification standard for IFC because we are creating a tool.
ArchiCAD, USBIM, AECOSIM, etc… has its own script in xml. I don’t mind… while the “Classification Standard for ifc in Xml” is not known, i can´t do anything. But with these starndard, my project modelers would+9 only have to create one for all software in a project (In my company we need some at the same project) and i woud have a good argument when talking with software developers.

Thank you again for your fast replied.


Sure, I agree. So using IFC (in particular IFCxml) as a neutral format to publish a classification should suit that. It would be interesting to hear which software vendors might recognize this in the near future. If you have suggestions about improving a classification definition within IFC, would be great to hear them.



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I can send to you:

XML for archicad clasifications
XML for aecosim clasifications
XML for usbim clasifications

Excel based on an exportation of ifc analyzer if an ifc with several clasifications

Word about feedback (mainly based on: several clasifications on the same element and why we need It as same as, several clasifications reference for the same clasification for the same 3d element and why we need It, mainly for Gantt chart and budget)

Just tell me how i can do that becouse i cant find the way in this plataform.

And again, the same about my cobie question. I need links of building Smart for processes and official script. In other case, i do not have enough arguments to being take into account.


Here is the standard for publishing classification in IFC:

It is in mvdxml format and the webpage shows a diagram of how the entities are connected.

(I changed the link to the new standards library location - @jwouellette)

thx @jwouellette

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Right now, most classification systems I’ve seen have the concept of only being able to link a single classification term from one table to an element. E.g. you can classify your object as either a beam or a column, but not both. This is also how ARCHICAD classifications work.

However, this often leads to very large and deep classification trees with lots of redundancies, just to cater for all combinations. E.g. in the Belgian BB/SfB, load-bearing and non-loadbearing walls are a different classification leaf. I’d prefer to be able to assign wall or slab or roof and then assign load-bearing or not-loadbearing separately. This makes the classification more concise.

E.g. can you assign two items from one Uniclass Table to a single element? I don’t think IFC restricts you in any way, but software such as Revit or ARCHICAD clearly do.


Yes, you’re right. I’ve only found one software, IFC Editor (USBIM VIEWER) that let us several clasification references.

We use this because in gantt charts you can assign one element to several activities (ej: for a column: concrete, painting… etc). Besides, this same element could be to a several budget topics (sorry, in spanish we say “partidas de obra”, i do not know the concept in english).

In the image you can see two Classification References for a column at one single Classification for Budgeting (INECOCLASS_Presupuesto_Puente): concrete and steel. (sorry, finally the website doesn’t allow uploading images… what unuseful for this blog…)

We had to enrich the ifc in USBIMviewer (ACCA software) but the image is from BIMVISION last versions that let us a Classification panel.

That example makes me thinking it is possible doing that in IFC but not in tipical authoring software…

The ARCHICAD XML format for classifications is pretty straightforward. It’s purely text-based, and there are not even GUIDS used whatsoever.

I have already created two ARCHICAD-compatible classification XMLs from an Excel sheet. and with some tinkering (e.g. escaping certain characters to make them valid in an XML) I was able to import them into ARCHICAD.

I’m pretty sure Graphisoft in general is open to standardisation from buildingSMART, but just like the IFC-mapping files for IFC import/export with Revit are bespoke for their application, ARCHICAD has its own internal bespoke formats.

Is this something that would be in the scope of buildingSMART?

As it stands, we can already describe IfcClassificationSystem and Classification Reference in IFC (in all supported formats: STEP and XML). But rather than developing empty “projects” with nothing but classification references, I think I understand that IFC can refer to external documents too. Is that what Jon was alluding to? I’m not sure how suitable IFC is right now with information spread over multiple files? Or multiple “documents” (could be in a database too). It seems useful to be able to refer to the same classification from different models.

I want to break down IFC and re-build it in another way
And I think the first step is: Develop a "classification based on IFC"

I’m practicing to find that can I control IFC tree schema with classification and reduce/clean the majority of general entities like IfcRoot, IfcObjectDefinition, IfcObject, …, etc?

About other classifications: If all other classifications have to come closer to support IFC, then why not develop classifications based on IFC from scratch?

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