Recently, much of our in-house BIM discussion has been about something that I refer to as modeling philosophy. The first time this came up was about a month ago, when we recieved our first 3D model from an architect (aloft from Fruchtman).
At first, I was thrilled beyond belief, but when I started navigating through model to integrate the construction schedule, I was a little disappointed. The reason? Fruchtman modeled aloft using a different philosophy.
When we model walls (or anything) in-house, we model the building how it will be built. Using the wall example (a block wall with gypsum on both sides): I model each layer (block wall, gypsum laters, insulation, etc.) as separate objects. My reasoning behind this: the block wall is built months before the gypsum is put up. I "model for construction".
Most architects model differently; they model the easiest, most efficient way possible. It makes sense for them, as most contractors don't have the capability to utilize a model. The Fruchtman model (I'm not picking on them here; it's just my only example of an architect-created model) was no different. The same wall (block wall with gypsum) was modeled as one object with several layers. They "model for design".
I'm sure there is probably another way to model as well. Consider the future, when we present owner's with an as-built model instead of as-built drawings. A sophisticated owner might use that model to assist with facilities management; they might want objects modeled a little differently. I guess I would call that "modeling for operations".