IFC - Material Export Issue for elements such as Doors/Windows

[CateSn_89]

Hi everyone,

I am experiencing an issue when exporting IFC files for elements such as doors, windows, and other library objects that do not have a true layered construction but only surfaces.

In the model, I created a property related to material coding and assigned it to the desired elements.
However, during export, the material is not displayed. In fact, when I open the file with an IFC viewer, I can find the custom property I created, but the "Material" field remains empty.

I also mapped the translator and enabled the material export option.

Thanks in advance to anyone who can provide clarification.

Operating system used: Mac Intel-based Ventura 13.7.8

[Laszlo Nagy]

Can you show some screenshots that illustrate the whole thing?

For example, setting of element in Archicad, showing Surfaces and Property values, relevant mapping in the Translator, and the values displayed in the IFC Viewer.

[CateSn_89]

Attributes - ClassificationCustom PropertyModel filterArchicad Element conversionArchicad DATA to exportMappingBimcollab Zoom viewerBimcollab Zoom viewer

[CateSn_89]

Through the provided screenshots, i have documented all the steps i performed to assign and export the element's material in  IFC File. Thanks so much for your interest.

[Laszlo Nagy]

Sorry for getting this late to this topic.

I reviewed all your steps.

I suppose that the expression that you used to generate the value of the "Codifica Materiali" Property in the Property Manager is the concatenation of the values of the three other Properties above it, so the value of the Property becomes "0-LGN-Legno".

I see that you mapped the value of the "Codifica Materiali" Property you created to the IFC Property called "Material".

I could not figure out what the screenshot showing the various Surface settings of the Window is for, maybe you just wanted to show that the value of your Property is the same as the Surface used for "Telaio Esterno" (and other surelements). You know, you could have mapped the value of this library part parameter to the "Material" IFC Property as well. But I did not see any such mapping, only the mapping of the value of the "Codifica Materiali" Property you created to the IFC Property called "Material".

Unfortunately, from your screenshots, I could not find out whether the "Material" IFC Property contains the correct value because there is no such screenshot.

On your last screenshot, which shows the "ArchicadProperties" group of properties: I can see the value "0-LGN-Legno" in the lsit of values for the row "Superfici", but that is not where the "Codifica Materiali" Property was mapped to. In the screenshot, you should click the >> icon on the right of the "Pset_Window_Common to see additional property groups exported to the IFC, and you should find the "ElementoCodifica" group, and the "Material" IFC Property under it that should have the value "0-LGN-Legno". That would indicate that the value was properly mapped and exported.

Now, about the "Material Name" field on your next to last screenshot, which you say did not get filled out: I believe that this is not a standard IFC Property or field, but a field specific to BIMCollab. I checked the exported IFC file in two other IFC Viewers, one of the being Solibri Anywhere, and neither had this field. I also checked, the IFC Schema, and there is no "Material" or "Material Name" or similar field in the IFC Schema. This makes me think that the reason this field is not filled out in BIMCollab is that it is a non-standard field. If you look at the same screenshot, you will also see other fields like Prefix and Phase that also do not seem like standard fields in the IFC Schema and they are not filled out either.

In summary, I think mapping the Property to the custom IFC Property is the way this can work and is expected to work.

[Patrick M]

Laszlo, could some of this have to do with the conflation of material as surface vs material as bMat?
Maybe I'm not quite up to speed on the GDL updates, but aren't doors/windows still technically using the pre-bMat system of extruded fills? or are they actually quantifying individual materials per bMat definitions from their scripts?

[Laszlo Nagy]

I don't think so, because Building Materials are still not implemented in default Archicad Doors/Windows. I just went through the whole list of parameters of this Triple Window and I can see only Surface parameters, and no Building Material parameters.

What I see is that the GDL script, prior to generating the PRISM_ geometries (for the frames, for example), it still uses the old MATERIAL command to specify the Surface attribute and the SECT_FILL command to specify the section fill.

In IFC, the equivalent of an Archicad Surface is the IfcMaterial. I don't see any confusion there. I think that every IFC Viewer has its own way of deciding what value to use or not use to fill out a field (in our case, the "Material Name" field) in case it does not have a specific IFC Property of the IFC Schema corresponding to it.

Grok AI tells me this about the "Material Name" field in BIMCollab:

"For the 'Material Name' property shown there (especially for elements like IfcWindow), it typically displays the name of the primary or most relevant material associated with the element."

I don't know if, in the case of an Archicad Window, there is a primary Surface. Maybe if we check the "Uniform Window Surfaces" checkbox, there is. 

However, as I said earlier, the Material Name field exists in BIMcollab, but does not exist in Solibri, for example.

Anyway, @CateSn_89, you could write to your local support about this, if you think this is a limitation, or you can post a wish if you want something like this implemented.

[CateSn_89]

First of all, thank you for taking the time to respond to my question and for carefully reviewing the workflow I used.

I confirm that in Archicad I created a custom property generated by the concatenation of three other properties, resulting in a final value such as “0-LGN-Legno”.

Regarding the screenshot of the window shown in the Archicad Properties section in BIMcollab, I shared it simply to demonstrate that in that field it is possible to correctly view the list of all the surfaces used by the object. In fact, the value “0-LGN-Legno” that appears in that list does not correspond to the property I mapped to the IFC, but is simply the name of the surface that I assigned within the model.

You are also right that I did not include a screenshot of the Pset_Window_Common section. In that section, I can see the property I created and mapped, and the value “0-LGN-Legno” is correctly exported in the IFC file as the value associated with the material. I  see this property correctly displayed in BIMcollab Zoom.

However, the issue arises during the model checking phase. The team performing the IFC model verification in Solibri reports that the material of the element is missing, even though the custom property I created is present and correctly populated within the IFC property set.

This behavior occurs with all GDL objects (doors, windows, and other objects), while for structural elements such as walls, beams, and columns, the material is correctly recognized and displayed.

For this reason, I was trying to understand whether the issue could depend on how I configured the mapping in the IFC translator, or whether the problem is related to the fact that windows and, more generally, Archicad GDL objects mainly use Surfaces rather than Building Materials. In that case, it could be that Solibri is unable to identify a primary material for the element, as you also mentioned in your previous response.

Personally, I believe that this second explanation is the most likely.

Thank you again for your support and for helping clarify this issue.

[Laszlo Nagy]

If you need IFC files to contain certain specific pieces of information, and Archicad does not export these (like this Material Name value), one other thing you can do is the direct editing of the IFC file and dat contained in it. There are applications that can do that. For example, Bonsai BIM is a free Blender Add-On (its former name is BlenderBIM Add-On) that uses the IFC Schema as its basis, so you can open, view, and edit IFC files in it. You can select elements and modify IFC Properties in it, then save the IFC file. It is even possible to use Python to automate such tasks. There could be other apps that are similarly capable of editing IFC files.

[CateSn_89]

I will try to follow this solution using these add-ons. In fact, I had already tried to open the IFC file directly with Archicad: the building material exported for the GDL objects is set as “Generic Ifc Building Material,” so I modified it directly. At the moment, I am still waiting for feedback to verify whether the change works.

However, this remains a not very immediate solution what I have done.

In my next attempts, I will follow your suggestion, hoping to achieve a more efficient workflow.