Badda BIM Badda Boom!
It would seem to me that many forms of BIM are just any implementation of Architectural 3D CAD applications. Autodesk’s REVIT, Architectural Desktop , Bentley Architecture or Graphisoft’s ArchiCAD are in their own right fully functional BIM applications. All of these applications existed before the BIM label was popularized. Clearly, many people ascribe more meaning to the special acronym BIM. Typically the modern buzzword BIM is married to another acronym IFC (Industry Foundation Classes) The IFC ‘standard” is a data standard for describing BIM. Its goal is to form a framework for BIM interoperability.
There are a lot of people smarter than me defining the taxonomy, data structures and applications of BIM, though 3D CAD architectural software, but what interests me is its usefulness as GIS content. The question I ponder as someone interested in GIS and CAD interoperability is, “what does BIM mean to GIS?”
I, like many are still in a wait-and-see mode for many of the details of BIM and IFC’s. However it is my gut feeling that one useful way to characterize BIM/GIS interoperability is as a form of CAD, (with more explicitly defined data schemas and that's a good thing.) Like traditional CAD applications there is a lot of flexibility in the implementation of Architectural 3D CAD applications and their interpretation of what BIM/IFC’s are, and can be.
There are several different ways one could interpret useful GIS and BIM interoperability. The easiest and perhaps most flexible would be the same way in which CAD data is handled. Like a CAD file a BIM could be opened as a Geodatabase where the objects in the BIM are abstracted into a collection of GIS Points, Lines, Polygons, Annotation and MultiPatch features. This type of view doesn’t even have to attempt to resolve all of the possible object hierarchies, collections or other relationships.
Another question worth asking is what type of file do we expect to interoperate with? Should the intermediate file be an IFC file, or the BIM’s directly in their own various flavors ? One might even consider a DXF file or the CAD file itself as the interoperable intermediate data format. If one were to express the BIM as simple CAD entities then the work of GIS is already finished. ArcGIS already knows how to read a CAD drawing… (depending on the entity types).
This topic deserves more of my time and energy; right now I think it may be to early to tell how the markets will respond. Will anyone other the owner-operators customer like federal/local governments be able to coordinate and fund a useful BIM, is that market, enough? Will the IFC taxonomy and data model definitions swell to accommodate all of everything so that the STANDARD becomes like a life size map of the world you keep in your back yard?