ArchiCAD and IFC Element Classification

[Brian Spears]

Does there exist anywhere a list of things that might be modeled in ArchiCAD and what the most appropriate IFC Element Classification might be?

Some are easy: Wall, Slab, Ceiling, Furniture, etc. But some...

What Element Classification is most appropriate for built-in cabinets / millwork? Furniture? For toilet accessories like grab bars or tissue dispensers? Building Element Proxy? What about things like rubber base or other trim? Covering? What is a Discrete Accessory?

I keep thinking there must be a list somewhere of what types of construction elements would fall into which IFC Classification, but I can't seem to find one.

Anybody run across something like that?

[Tim Ball]

There is a full list of UK uniclass classification codes for Uniclass 2 here
http://www.cpic.org.uk/uniclass2/
Same thing for uniclass 1 here
http://www.cpic.org.uk/uniclass1/

Uniclass 1 is being phased out but uniclass 2 is not yet complete but it might help you with your classification issues as the search box is good

[Brian Spears]

Thanks, Tim. I had overlooked adding my Location to my profile. I've done that now. I'm in the USA and don't use Uniclass, but I am beginning to become familiar with OmniClass.

Also, my question was maybe not clear. Rather than a national or international classification system, I am looking for a list to help myself and my Users begin to understand what ArchiCAD Element Classification selection (in the Tags & Categories Panel) to use if "ArchiCAD Type" is not appropriate and if not, what is the best-fitting ArchiCAD Element Classification, if it is not readily apparent or obvious to the User.

When we model a floor slab on grade, we could leave the ArchiCAD Element Classification set to "ArchiCAD Type", or for consistency, I'd like my Users to know which more specific Element Classification to select from the list. In the case of the floor slab on grade, selecting "Slab" is fairly easily understood. If we model a ceiling using the Slab Tool, we can easily understand to select "Ceiling" from the available options when selecting an ArchiCAD Element Classification.

However, if we are using the Object Tool, I'd like to know which ArchiCAD Element Classification is most appropriate for a whole bunch of things we typically have in our models. For Objects, if we don't specify but leave it set on ArchiCAD Type, it will export to IFC based on its Object Subtype. In the example of casework, if we use an ArchiCAD Library Part, for example: Cabinet Base Double Door 18, that Library Part has the option to turn on a sink and tap. That Object also has an Object Subtype of "Flow Equipment", which is a Sanitary Terminal in IFC. So if we are modeling a kitchen and use multiple instances of this Base Cabinet in different configurations, if we don't specify an ArchiCAD Element Classification, at export to IFC, each of these Base Cabinets will export as Sanitary Terminal, whether it has a sink in it or not. I think I found on the buildingSMART website that IFC standards think of casework (whether built on site or factory built) as similar to furniture and should therefore be IfcFurnishingElement.

So I found my answer for casework, but for many of the other things that we model, I'm looking for a list (potentially just a user-created list) that helps understand a "best practice" ArchiCAD Element Classification setting for the non-obvious ones: gutters and downspouts, grab bars and other toilet accessories, toilet partitions, fire extinguishers and other types of equipment like residential appliances, wall trim... I think Building Element Proxy is a catch-all category for element types not yet defined in IFC2x3, but surely some of what I'm looking for can be classified in some way and not have to be lumped into the broad and generic Building Element Proxy.

Thanks again, and I apologize for not being clearer in my original post.

[Tim Ball]

The Archicad classification is not really very comprehensive but it does follow through to the IFC data. So for instance if you model a ceiling as a slab, but don't change the type to ceiling instead of slab, IFC will read it as a slab not a ceiling. Sounds obvious but that can screw up your IFC checking.

You could do some tests to see what IFC export does to different classifications that are important to you.

One useful thing to use is the building proxy setting. If you change a mesh for instance to building proxy, you can then attach IFC data to it.

This is all developing at the moment and I am not aware of any really well thought through system. I am sure that will happen in time, but for now a lot of data management is trial and error.

But just trying these things out means you are ahead of most users so do persevere

[Brian Spears]

Thanks a lot, Tim!

I'll set up a sample file and export a little Morph army: one set to each ArchiCAD Element Classification option and see what I get!

I've been using Solibri Model Viewer to view my IFC files. I've got Tekla BIMsight as well, so I can take a look in both.