Wow! MASSIS framework seems to do some terrific things with Sweet Home 3D, and the video shown at the home page of MASSIS framework is amazing.
Do you work on this project, or do you happen to use it?

At the moment, there's no support for BIM/IFC in Sweet Home 3D but that would be nice. Some time ago, someone started a project for this purpose but it doesn't look like he went very far [:(]

Converting IFC files to OBJ files should be a solution, but OBJ imported 3D models are considered as a whole object / piece of furniture in Sweet Home 3D, making it difficult to arrange this kind of home.