Model exchange with Autodesk Revit®

[Szabolcs Miko]

Is there a better alternative for model exchange with Revit® then the IFC workflow? No, there isn't. But there is a way to have a limited, direct connection. Use RFA & RVT Geometry Exchange Add-On to import and export 3D models via native Revit file formats. This Add-on is available on Archicad versions 21, 22, 23 and 24.

What kind of files could we receive from an engineer working in Autodesk Revit®? It has 4 file formats of its own: RTE (template), RVT (project), RFT (family template), RFA (family).

It's unlikely that we should need receive a Revit project template or a Family template, so let's focus on the ones that we need to be aware of:

• Probably the one of the most common scenarios is that the engineers will send an RVT file (instead of an IFC), Revit's native project format
• RFAs, so Revit families are similar to our Objects, they can be loaded into the file or saved externally. A number of BIM libraries are creating GDL object, which are available, we have a summary page on our website, but there are some out there (e.g. BIM Store, NBS Library, MEP content) which mainly focus on delivering Revit families.

RVT and RFA files

The three Revit Exchange functions are described below:

• importing 3D geometry from RFA object files and creating GDL objects. Look for File > Libraries and Objects > Import RFA as GDL Object)
• hotlinking 3D model geometry from RVT project files (RVT format will be available when adding a new hotlink module). Look for File > External Content > Place Hotlink)
• exporting the 3D model geometry directly into the RVT file format. Look for File > Interoperability > RVT Export in a 3D view

You can check the detailed and informative FAQ on our website:

What are the major differences between linking RVT and IFC files?

IFC is a better format if you need more intelligence. Using the IFC format for data transfer you can create native Archicad elements (e.g. wall, slab, grid etc.) from a Revit element by keeping several properties intact. The RVT interface imports geometry information which is very limited for post processing in the Archicad project – with primary purpose being on coordination. Features that IFC can provide over the RFA & RVT Geometry Exchange Add-on:

• Conversion to real parametric BIM elements
• Place associative dimensions on the linked elements
• Carry profile or composite information of a structure
• Carry non-element information (project hierarchy, element assignments etc.)
• Filter the model content during the import process Use the survey point data
• Create native GRID elements

Does the RFA & RVT Geometry Exchange Add-on compete with or set back OpenBIM or the drive for IFC??

OpenBIM is about being open. The RFA & RVT Geometry Exchange Add-on extends Archicad's ability to collaborate with Revit users and solutions. It is not intended to compete with IFC any more than DWG/DXF or Sketchup™ compatibility does. IFC is still the route we encourage users to take if they need full model exchange between any other software.

What type of GDL Objects can be created with RFA & RVT Geometry Exchange Add-on?

Objects, Doors and Windows can be created. These will be determined as best match depending on what Categories they were assigned in Revit

What RVT version can we hotlink?

Currently the RFA & RVT Geometry Exchange Add-on can hotlink RVT versions 2015-2020.

What Revit version can we export to?

Currently the RFA & RVT Geometry Exchange Add-on can export to Revit® 2020. 

How are Archicad elements converted to Revit elements?

Currently the elements are converted to Revit DirectShape interoperability elements, that use a fixed Category based on the Archicad element type.

If we talk about OpenBIM and support the IFC based data exchange, which gives the best interoperability results, we don't have to deal with RVT and RFA files at all.