It would be nice if gbXML / Trace used something other than the space name/id as the unique identifier/key. I thought this is what the intent of the CADObjectId was within the gbXML schema - at least this is what ABS uses it for. Unfortunately Trace doesn't seem to use it this way and so the engineer/designer is forced to use static space/room names if they wish to maintain any previous input within Trace. I'm probably preaching to the choir since this seems to be something that CDS would have to address and not Autodesk. I've also sent an e-mail to CDS, but thought I'd post here as well.