STEP vs IFC

[mat_hijs]

I tried exporting a model both to IFC and to STEP. The IFC file is about 785 MB and the STEP file is only about 14 MB. The IFC file also took a lot longer to export than the STEP file. I also noticed that within the IFC file there were some issues with geometry not being correct. I'm not authoring any extra information like classes in the IFC export and neither am I looking to do so.

The reason for exporting is for the main contractor, architect, ... to be able to check dimensions, have a visual and possibly do some clash detection (even though I think that's still rare).

Aside from file size and export time, what are the advantages or disadvantages of using one over the other?

[YannickEnrico]

IFC needs to mapped properly as it's table driven. You risk the architect running into tons of mapping errors, for instance, because some programs / tables name the same profile IPN or INP / UPN or UNP.

STEP is the export as is to a dumb format that can't just be mapped to anything else.
I would go with STEP unless the architect specifically requested IFC for whatever reason.

I have seen fewer STEP errors than IFC errors in my career.
That being said, I only worked for about a year in Advance Steel where we would sometimes use IFC.

[mat_hijs]

I don't use any standard content so the mapping thing probably wouldn't affect me too much.

Usually they'll ask for an IFC, but I'm guessing that this is largely because that's the industry standard in AEC. Also, I'm not 100% sure but I believe that Revit can only import or export STEP files since the last release.

[YannickEnrico]

The mapping thing is not an issue for you as the exporter - But it might be a huge issue for the architect as the importer.

Alternatively, export it in DWG format. AutoCAD will read it as 3D solids

[mat_hijs]

What I meant with the mapping thing is that I think everything will be mapped as a generic model anyway.

[YannickEnrico]

Yeah, but what I mean about mapping, is that you risk something you drew as a HEB100 profile, being imported as UNP300 profile, because it's table driven. Hence DWG or STEP format is easier to handle, as it just exports the true geometry.

Because of how IFC works, you ALSO risk it not registering miter cuts or rotations of profiles properly.

[James_Willo]

Hi, most architects if they're using Revit won't be able to use a STEP file as only Revit 2025 can import them (from what I understand this was a new feature.) IFC has been supported for ages. 

Also, there were occasional issues with geometry of Inventor created RVT/IFC due to the intermediate file type that we use during translation, this has been fixed in Inventor 2025. I think this is also fixed in 2024.3 and 2023.5 so it might be worth checking you have the most recent updates. 

We were using DWG previously so exporting Inventor to DWG and into Revit might produce the same issue.