To be honest, My Navisworks experience is limited, though growing daily. I have to deal with a few collaboration packages and Revit would be a nightmare if it weren't for dwf/dwfx. Revit is basically a 3D extrapolater for a relational database. This is why there are absolutely no translators for .rvt files (you can open an .rvt file wrapper with things like 7-zip which shows some of the underlying structure...). dwf is a 3D file format, which exposes the geometry and associated parameters without the intelligent relationships.
The heirachy I am talking about is basically identical to the heirachy one meets in revit through visibility/graphics, or in the project browser under families (both system and loadable). I am told that the same is true for all other packages that export to dwf.
When opened in Navis this heorachy is maintained allowing isolation of any particular type of element, or by drilling down to a sub level family, all conveniently listed by name and type/subtype. Unless specifically included, only basic parametric information, i.e. Name, GUID, length, material and width are included to keep the model light. Nested Shared Families are also included as separate entities with their own parameters.
I could sing other praise about dwf (which amazingly is native to Autodesk!! Yep you heard right, NOT BOUGHT BY AUTODESK!!?!) though this is not the correct forum. There are 3D exporters for CATIA and Pro steel (I think) to dwf and I am sure the number will grow. It would be advantageous for GS to look at this as I have a sneaking suspicion (IMHO) that this may be the future collaboration format (sorry IFC). It is not being groomed as this, though it definitely has the potential and credentials.
