Product(s):	OpenBuildings Designer (and AECOsim Building Designer)
	Version(s):	CONNECT Edition
	Area:	Import/Export
	Subarea:	IFC

Problem

I've found that the IFC Import tool doesn’t include the ability to map IFC classes to native OpenBuildings Designer component types as well as Family + Parts like the IFCIN keyin does.  We've also noticed that file sizes when using the IFC Import tool are also smaller.  Is this difference in behavior expected? 

Solution

Yes, this difference is expected. The IFC Import tool available from the Backstage serves the same purpose as the File Open and Reference Attach dialogs when the file extension filter set to IFC, both of which were originally introduced in MicroStation V8i.

  

The IFCIN key-in, on the other hand, is the older OpenBuildings/AECOsim IFC Import tool that was available before MicroStation itself had the ability to open or reference IFC files.

This is why the Backstage option results in a smaller file size - it is translating only the graphics. The IFCIN tool brings across those graphics as well, but also maps IFC entities to DataGroup catalog items hence the larger file size. And since IFC is essentially used as a coordination format vs. a parametric model exchange format, the focus in CONNECT Edition is on the MicroStation method since the file sizes are smaller while still maintaining good graphics fidelity.