BIM Collaboration Format (BCF)
When you exchange BIM data using IFC, you probably also want to communicate about the objects in your model. Doing this over email, or using the phone to comment about 'the 3rd column from the right on the 2nd floor' brings risks and unclarities. This is why the "BIM Collaboration Format" (BCF) was created.
The BIM Collaboration Format (BCF) allows different BIM applications to communicate model-based issues with each other by leveraging IFC data that have been previously shared among project collaborators. BCF was created for facilitating open communications and improving IFC-based processes to more readily identify and exchange model-based issues between BIM software tools, bypassing proprietary formats and workflows.
Further information is here on BIM Communication - No Problem with BCF. Technical information about BCF can be found here (xml) and here (API).
You can learn more about BCF with the user guides listed below.