Export finishings only (no structural elements), as IfcCovering

[Anonymous]

Hi everyone,

We had "a first" for one of our projets: the main contractor that is in charge of coordination wants our IFC model to include only non structural parts for the next stage of the projet. Meaning a composite wall or slab, for instance has to have only its "finishings" and "others" exported.

The only workaround I can think of is to use the "export only the elements with materials that participate on collision detection" activated and temporarily change that option for the structural materials. We have tried and it works. However, composite walls are assigned classification "ifcBuildingElementPart" and we need it to be "ifcCovering". My guess is that is impossible to do this on archicad because I cannot map one part of a composite, right?

Any ideas or other workflows? thank you in advance.

[Laszlo Nagy]

There is another way I could think up and I tested it and it works, although it takes several steps. The plus side of it is that you do not need to tamper with the settings in your Project. You will just have to play with IFC Export Settings.
This is for AC23. (In AC22, some IFC options are different and I have not tested those).

In the "IFC Translators" Dialog, go to the "Geometry Conversion for IFC Export" Dialog, and make sure that two options are set properly.
Option 1: the "Use BREP geometry in current color for all elements" checkbox should be checked.
Option 2: the "Material Preservation mode (IFC 2x3 only) fields should be set to the "Explode All elements into parts, preserve materials" option.


As you can see, the second option is IFC2x3-only.
So, if you save as IFC4, you can alternatively use the "Split Complex Building Element into parts" checkbox, and check the "IfcBeam", "IfcColumn", "IfcRoof", "IfcSlab", and "IfcWall" checkboxes, because these are the 5 element types that can have a Composite Structure or a Complex Profile. You can use this as an alternate for Option 2 in case of IFC 2x3 as well.

With these options set, when you export to IFC, all Composite and Complex Profile elements will be split into their Skins/Components, but what is more important is that when you open this exported IFC in ARCHICAD, they will come in as separate, individual elements.

You will then have to go to the Layer Settings Dialog and unlock all Layers to which the IFC was imported.
Then make sure that Groups are Suspended.

Then you can use Find and Select to select and delete all former Composite Skins and former Complex Profile Components (which are now individual elements) that have structural Building Materials. Similarly, you can select various skins with Find & Select and set their Classification (to Covering) so they are converted to the desired IFC Types.




Then you can resave the result as IFC and that will achieve the desired result.

I hope this explanation makes sense.
As I said, it is several steps, but at least you don't have to modify the settings of those Building Material attributes.