Export to IFC Units

[seanjames]

When exporting an IFC file is there a way to change the units from metric to imperial? We are working with an Architect using Revit and they are telling me the units for the imported file are metric. All of our templates are imperial and I cannot find a setting to change the units for the IFC file.

I came up empty when searching.

Thanks,

[bradg]

Hi Sean,

We ran into a similar IFC unit problem when working with an architect using ArchiCAD. Even though we're using inches and (they say) they're using inches, our ductwork etc. would come in off scale. What we ended up discovering was that in order for our 3D objects to come in at the right scale, we had to convert our drawing units to mm before exporting to IFC.

Here's the process I use:
1. Copy the files to my local hard drive (so that the originals remain unchanged).
2. Go to Format > Drawing Setup > Units tab and change the Drawing Units to Millimeters
3. When prompted, select the first option to Rescale Model and Paper space Objects
4. Save the drawing (I usually Save As and add a mm suffix to the file name, just to keep organized)
5. Export the IFC as usual

You may need to figure out which units you need to rescale your drawing to. To figure ours out, I had the architect send us dimensioned screenshots of how our IFC imported on his computer. It turned out that it interpreted our units as mm (i.e. 20in = 20mm), and our model was super small. That's why we have to rescale ours to mm.

Sorry for such a long post, hopefully this helps you out; it's kind of a pain (I'm in the process of exporting IFCs as I type this), but it goes quicker over time.

-Brad

[seanjames]

Brad,

Thanks for the Reply.

Ours come in just fine, elevation and size wise, but they are complaining about the units being metric. They want me to come up with an answer that doesn't seem to be documented anywhere I've seen. This is the only thorn in my side with the whole AutoCAD MEP to Revit conversion.

Thanks,

[danielbritt]

i am having the exact same issue. i did a search on here in late april and didnt find much on it, so im glad im not alone. my client keeps asking me to rescale the files that come in as mm; i know their cad person fixes it as needed, but the PM keeps coming back asking for rescaled files.