Archicad 25 elements not converting properly in IFC conversion to Revit

[David Larrew]

I've tried all IFC Translator settings with no luck. Archicad 25 elements (walls, slabs, roofs,...) do not translate to their proper element types in Revit. The direct .RVT file conversion also doesn't work correctly. The elements show as unusable "general model" types. My architectural clients are getting backlash from Revit consultants, they are unable to use the converted model files effectively. And the Graphisoft Revit plug-in doesn't seem to help either.

One of my largest local clients just bought their 1st Revit license to help us figure out what is going on. Unfortunately, we have not found a solution on the Archicad side.  There are growing rumblings of converting to Revit completely just so they can work with consultants (100% Revit users). I'm running out of ammo to defend Archicad as their best BIM solution. It is a shame, because I've been using AC since 1997 and always thought I was using the best BIM solution. Come on Graphisoft, you need to step up your game if you want to compete.

[NandoMogollon]

Hi David,

IFC is intended for a very good Information and Geometry exchange, but not for round trips (it was never intended).

Nevertheless it is possible to achieve a very good rate of conversion with the correct translation settings in BOTH Archicad and Revit. 

This means that even if your translation out to IFC is perfect, Revit needs to read the IFC just as good. I work regularly helping my clients doing this and still achieving a good rate of success within the limitations of - have to be said - of Revit when it comes to translate the files to internal Revit geometry and tools.

A few recommendations:

• By all means have a purpose built translator out
• Use Extrude and Parametric geometry when possible instead of BREP. This will write an IFC with better instructions for Revit to rebuild the main elements
• Include 2D lines and Symbols in the translation
• Do not exclude materials that do not participate in collisions
• Consider limiting the additional data to be included as they may not need all PSets. Perhaps limit it to attributes and PSet_Common properties
• Consider reviewing and validating the exported IFC in a viewer before sending it out. That way you will have peace of mind that the model has the information you need.

Hope this helps /it should.

[David Larrew]

Thanks for your reply and encouragement.

We are not trying to use the IFC round trip, we only need the IFC model elements to be converted correctly in Revit. We have tried the settings you listed numerous times, and inserted the IFC files into Revit (the copy they bought for this). The Walls are converted as "general model", Slabs are converted as "general model", Columns are converted as "general model", etc.

The consultants need the converted Walls to be actual "Walls" so they can attach/associate their Revit Family elements, which is impossible with "general model" elements. We are currently working on the Revit side to see if we can fix the conversion issues. I'll report back if we find anything. Thanks again.

[stefan · Accepted solution]

I've had the experience that the IFC import in Revit is often falling back to Generic Models whenever anything in Archicad makes more complex geometric connections. Solid Element Operations don't translate that well, so the geometry is often flattened down to Boundary Representations, which will often lead to Revit importing them as "Generic Models". Try to see if it it makes it easier to disable roof/wall connections. It may even be helpful to have separate exports for walls, slabs and roofs (which are the primary "system families" you'd want to reconstruct at the Revit side).

[David Larrew]

Thanks, Stefan, we've had to do that in the past just to keep the IFC file size down, but now it looks like we will have to split the IFC file up just to get clean AC-Revit conversions. Once again, us AC users have to jump through hoops to work with Revit users. I think GS needs to include a license of Revit to allow for true collaboration with consultants. Yes, I know that is a joke, but that is the way I feel right now.

[stefan]

Define "collaboration". In a recent large project, while primary exchange was IFC-based, the team using Archicad exported an RVT file as well, which seemed to be more convenient for one of the other teams. But that was for "coordination" purposes.

For "design transfer", you'd have to jump to such tricks to get the maximum out of it. This is not for frequent coordination, but for a one-time transfer, where some reconstruction work at the receiving end can be expected and which is more or less acceptable, to get more performing and conforming results, the way e.g. the team in Revit expects their model to behave.

[Eric Milberger]

I am facing this as we will have to make Archicad or Revit our choice on our next project.  One or the other.  I’ve played and Archicad will still need a polished template for me to use but it is the winner or Revit hands down EXCEPT.  I have no Engineers to work with.  None.  And the time to for me to make the Revit files in my model and update daily to monthly is too costly.  The problem here in the US is there are literally no Engineers to work with.  Remember even though we are remote it is necessary to meet in an office at least monthly and flying for that is not an option.  We work by internet with Engineers and have for over 25 years.  But you still can’t build local work if all your works goes to companies in other regions.  So a better marriage with Revit is mandatory not just necessary.

[David Larrew]

This current consultant is an MEP engineering firm. They are using the AC-Revit converted BIM model to place their MEP elements and document.

My client requires all design team members to work in BIM. In the past, they were having 3D coordination issues with consultants not using BIM. Most structural engineers are using the AC-Revit converted model as a reference to coordinate their Revit model elements, and we reference the structural models into AC to coordinate on our side. We haven't had much luck actually using the Revit converted models in our project models. We have found that MEP/civil engineers tend to be the last to utilize BIM, so we are having to work a little harder to pull them into the BIM workflow.