Category Archives: IFC

IFC Element Classification

Recently, we have noticed projects exporting IFC files incorrectly; specifically with missing content. Wether this is due to changes to ARCHICAD from IFC2x3 to IFC4, or if it is just a modeling error on our part, is difficult to pinpoint at this time. What we have determined is the issue is the result of Element Classification going missing.

The Element Classification is the little drop down at the bottom of the settings dialogue for each model element. You can locate this within the Categories and Properties tab of the element settings.

screen-shot-2016-09-30-at-1-34-42-pm

It can be easy to ignore this setting, since it really doesn’t impact our typical model or document process. But for IFC coordination this setting is critical. If this goes missing, the element will not save out.

So a missing or undefined classification can get in the way of effective collaboration, but so can an incorrect classification. An example I have seen is doors that were used as gable end vents/walls. Because the door’s classification was left as “Door”, it was read as a door on the Revit side. This resulted in the door and the wall were defined as an opening that penetrated the roof; the engineer had to ask for a correction from our end.

screen-shot-2016-09-30-at-1-53-48-pm

IFC Classifications can seem a little confusing, given the unclear and vague terminology used in describing each classification. But fortunately Bond Bryan has already done the leg work to define each element classification and what is included. I have in turn reinterpreted this list in our BIM Manual for our calibre of projects; you can view this Dictionary of Element Classifications under Collaboration > IFC Classification in our BIM Manual. Or for a more complete list of building components and their Classifications, see Rob’s list here.

Latest Schedule Information

For anyone working on a project started after the release of Template 18.2, we have a new system for scheduling non-door & window objects. Rather than using independent schedule tags, which are duplicates of most of the model elements they represent, I have mapped an IFC system to match the previous naming and identification system.

The advantage to this is that any object can be scheduled together, requiring fewer (or no) tag elements to create a schedule. The section you want to look for in the element selection settings is at the bottom of the settings window under Tags and Categories > IFC Properties, and should look something like the window below:

Screen Shot 2015-06-29 at 4.41.53 PM

The 01 QTY, 02 ITEM… fields replace the tag settings for all objects, including the tags (in case they are still needed for some hardware elements or surfaces).

If the IFC Properties field does not match what is shown above, it is simple to bring them up for any object. These 7 fields have been mapped for all object types in the latest template version. Just click on the Manage IFC Properties… button at the bottom to bring up a window like this:

Screen Shot 2015-06-29 at 4.31.08 PM

Screen Shot 2015-06-29 at 4.40.11 PM

Open the Pset_ManufacturerTypeInfo… section and check boxes 01-07 and click OK.

Next check the specific schedule settings you want any element to be listed under. In the Criteria section look for the Name (Attribute) starts with line. For plumbing fixtures, the abbreviation is PF. This field is up in all IFC settings, and if you notice in the first image I have called the toilet under its IFC parameters to be called out as PF-TOILET 1. Now any additional fields filled out in items 1-7 added to the IFC settings list will populate the schedule:

Screen Shot 2015-06-29 at 4.47.42 PM

I will admit, this does potentially require an additional step (until I get the favorites updated to include these settings), but it does mean that literally anything can be scheduled together. Quite literally, it is possible to schedule a column, slab, wall, etc. element with the plumbing fixtures, hardware, etc.

If this is a little confusing at first, let me know when you get into scheduling, I can do small group or even one-on-one desk sessions to clarify. I think ultimately this will make scheduling a lot more flexible and easier to manage.