You may be unfortunate enough to have to translate a BIM model from ArchiCAD into Revit. I have done this in the past (with limited success) using IFC.
However, I was browsing the AUGI Forums today and came across this post, which recommended the use of Solibri IFC Optimizer. This is a free Java utility that launches from your browser (you do need to register first). You then feed your IFC file into it, and it, well, optimizes the file.
I gave it a go and it reduced an IFC I recently worked on from 21.6 mb to 13.7 mb – so it actually does work.
Check it out if you are using IFC…