About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
Rob,
Not sure what export options Lumion has but if imported in sketchup format will be imported as an object that you can then convert to morphs, you will not be able to import it as walls doors windows etc as this is not available in the skp format. Will only really be useful to help trace off and rebuild the model from scratch
Scott