Civil users do not BIM exactly, what we typically produce, IS later fed into, or up to a GIS network.
Sadly, all of the 'export' modalities that Civil 3D offers, does NOT generate GIS ready information; as one could do with Land Desktop. Autodesk, needs, or must reintegrate MAP, with C3D objects, and allow us direct access to the object, and it's built in intelligence (properties) such that one could SEAMLESSLY use the BIM information that one is already generating in the process.
Not create the intelligent model, then export it in some STUPIFIED format, groom that data to add the intelligence that was just stripped out of it back in and then use the data in our BIM (that would be GIS system; as the 'building' we are building is infrastructure, not houses and buildings)
I already know that I am already doing BIM, now I just wish the software would.