You know, since everything is going to be CG but you want them to be real and not ACTUAL CG, why not just make detailed miniatures and edit them in? why go through the effort to make them all large scale? Not convinced? go watch Hunt for Red October. All the sub scenes were miniatures (not THAT mini, but still). another? Star wars. LOTR. The list goes on. Miniatures are a great way to add set items that would be too costly/labor intensive to make full scale.