by Dennis Collin
I was recently asked whether AutoCAD Architecture could open IFC files. IFC (International Foundation Classes) files are an open format designed for users to be able to transfer building Information models (BIM) between different platforms. For example, ArchiCAD to Revit or similar.
The venerable DXF format only supports legacy CAD elements such as lines, text, layers, and generic solids. Whereas IFC understands intelligent element classes such as walls, doors, slabs, beams, and columns etc. Such entities are common in any BIM model file such as Revit.
AutoCAD Architecture is one of AutoCAD’s toolsets and like Revit can create such elements as walls and doors etc. It can also access files from other BIM platforms via IFC but depending upon the document state of the software the option to open an IFC file may not be apparent.
Fig 1. AutoCAD Architecture application menu initially doesn’t seem to support IFC, but it does!
The solution is to start a blank drawing document i.e. have the software in a non-zero document state! Once an existing drawing or a new blank template file has been accessed. The ability to open an IFC file will be apparent within the application menu. (See Fig. 2)
Fig 2. Once a drawing has been accessed, it is possible to ‘open’ an IFC file
To see the open IFC option, start a new drawing and then access the open IFC file command.
Fig 3. Configuring the IFC import process.
AutoCAD Architecture will then ask for the location of the IFC file, where it should save the resultant project drawing and the AutoCAD template from which the conversion process will use. The translation process will use this file for units and style naming purposes.
Fig 4. An IFC now converted to an object enabled DWG file.
Once complete there will be a host drawing, with a multitude of external reference drawings, where levels or storeys from other BIM packages get converted as separate drawings. Linked to the world UCS origin.
Fig 5. External Reference are named according corresponding references in Revit
AutoCAD’s etransmit command illustrates how AutoCAD Architecture sees the drawing, where Xref names are generated from the corresponding level names from the original IFC authoring Revit Project.