behind the scenes of "export to IFC"

[a.aroesti]

Hi,

we are using a lot the exporting to IFC and sometime it fell like a black box.

for example :

• It seems that the export engine to IFC creates some relationships between Model elements and Rooms. If it's not clear enough see the attached image. All those elements have been modeled normally in Revit without any special action. in the picture (taken from IFC viewer) you can see how elements connect to Rooms.

• using different MVD getting different model break down (not only parameter). for example i found out that when using "Coordinate view" setting will export the curtain walls with the parent element not only the panel , mullions etc. when using "Coordinate view 2.0" it doesn't, it exports only the panels and mullions without the DATA of the parent element. anyone could shed some light on this? or generally what are the difference between MVD in details? 

thanks

[jeremy_tammik]

If it feels like a black box to you, you can easily dive in and open it, analyse exactly what it does and how it achieves that, and even modify it freely, since it is all open source on GitHub:

https://github.com/Autodesk/revit-ifc

If you have any specific IFC related questions, the best place to discuss those with the real experts in the area is the IFC discussion forum:

https://sourceforge.net/p/ifcexporter/discussion/general

[eason.kangEDLV4]

Hi,

(This is a duplicate case to Forge Help no. 13032, so just paste my replies here for reference)

IFC2x3 and IFC4 are IFC definitions (IFC Schema) defined by buildingSMART. Commonly, we can consider it as the File format representing the BIM model like Microsoft Word (DOC vs DOCX).
 
Coordination view, FM Handover, and Reference View are IFC MVD (Model View Definition) for providing specific data of exchange on top of the IFC Schema. It may contain the data of the whole model or just parts of it. You can find the full specs here:

• https://knowledge.autodesk.com/support/revit-lt/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/Revi...
• https://damassets.autodesk.net/content/dam/autodesk/draftr/2528/180213_IFC_Handbuch.pdf
• https://technical.buildingsmart.org/standards/ifc/mvd/
• https://technical.buildingsmart.org/standards/ifc/mvd/mvd-database/
• https://www.buildingsmart.org/standards/rooms/building/fm-handover/
• https://www.linkedin.com/pulse/ifc-mvd-ids-whats-all-vitalij-tetervov?trk=pulse-article

I'm unfamiliar with all IFC Schema and MVD, but as I know, FM Handover is an extension of IFC 2x3 containing COBie data for facility management.

The room-element connections could be related to the 3rd-party IFC viewer. From my experience, some 3rd-party IFC viewers will do some extra mapping while parsing the IFC file. So, I'd suggest checking that with different IFC viewers (e.g. FZKViewer, BIMvision, BIMcollab Zoom, etc. ) to see if it can also show the connections.

Lastly, for IFC-specific questions, please follow Jeremy's suggestion.

Cheers,

[a.aroesti]

Hey @jeremy_tammik ,

i didnt find an answare from the attached link.

maybe you can focus me on specific place?

my question is :

is during the export to IFC from Revit, the system create relations connection between elements and zones(rooms)?

thanks

[eason.kangEDLV4 · Accepted solution]

Hi @a.aroesti,

As I mentioned above, the answer is no. I checked serval exported IFC files in different MDVs. There is no such relationship exported. So, that's why I said the relationship might be rebuilt by the 3rd-party viewer you used while reading the file.

Cheers,