The most common problem when IFC files fail to connect is the total size of the IFC file.
The current version of the model connection in the dRofus client operates in a 32 Bits environment. Which means it can hold, at most, 4 billion (4 000 000 000) BIM objects/references. So what does this mean? This mean that it's actually not the model size in bytes that determines whether the model is too big or not. It's how many objects/references all IFC files in the model consist of. However, out of experience we usually advise our users that total model size should not exceed 300 mb when using the model connection technology in the client.
Suggested solutions to reduce file size
There are several ways to reduce file size of IFC files in BIM projetcs. In this section we will point to two possible ways:
Limit the export in your BIM authoring tool
Most BIM authering tools have functionality for excluding specific objects from the IFC export. One example is Revit's "IFC Options" described in "IFC export from Revit to dRofus" on this page. If you struggle with large IFC files it may be a useful exercise to consider if certain objects can be excluded.