IFC vs 3D DWG

[Eliot Black]

We are about to kick off a highly detail project requiring precise coordination. Our office will be handling architecture and structure using Revit 2011 respectively. We have a MEP consultant that will be using Autocad MEP (I am pushing for them to switch to Revit, but I don't expect to be successful).

What is the smoothest/easiest method to have them send me their coordination model? IFC or 3D Dwg. Our documents are required to be near shop drawing detail level, so speed and smoothness are key, as well as being able to easily coordinate systems and interference check (we will be using Navis for that most likely). Is there another work flow that could work more efficiently?

[brethomp]

I'm surprised no one else has responded to this yet. Anyway I can offer up a little of our experience. I don't know that we have found the best solution, but it is a mostly working solution. We are in a similar situation on one of our projects where the architecture and structure are in Revit and the MEPF is in AutoCAD.

So far we have had the best results with IFC, although it does have it's issues. One being that the files do get huge.

If you have a multi-story building, it is very likely that the MEP engineer will have separate DWGs for each floor and each discipline. This creates dozens of DWGs, which would be a pain to export and import one at a time, each time. So it's helpful on both ends to build a single DWG file for each discipline that xrefs all of the floors together at the correct height, and Export to IFC from that file.

Opening the IFC files in Revit creates a RVT file, that you can then link into your project. The IFC files can get huge, so it's important to put each of these links on their own workset, so you can skip loading the worksets when they are not needed.

Many objects get messed up through this process. I don't know if it's a problem with the AutoCAD export or the Revit import, but you will loose some objects.

None of the object meta data is maintained, everything just comes in as a Generic Model. But the layers color stay for the most part, so if you know what the colors mean it usually isn't to difficult to tell what things are.