What are the benefits of adopting Building Information Modeling?
BIM promises that you can work through the entire design of your building to completely constructible levels of detail. This leads to better and more complete design decisions made before the first shovel hits the construction site.
Decisions made during the design phase of a building are much more cost effective than decisions made after the concrete has started curing. Additionally, decisions made during design are typically better, more thorough and carefully considered. Design improves with iteration, and BIM permits that when properly used. Nobody likes to discover design problems on site when there is no time to consider alternate solutions.
While I think most folks would ultimately agree with the definition above, many still think of BIM as a class of tool that you can just buy and learn how to use to get yourself a fully capable BIM process. Unfortunately, it is a bit more complicated than that.
At its heart BIM is a methodology, not a tool. 3D modeling (detailed or conceptual), energy analysis tools, drafting automation and parametric object definitions all have their place in a BIM process. But BIM is defined essentially by none of them. You can do very effective constructible simulations of a building using many diferent applications. Some people do so using only a spreadsheet.
If there was one defining characteristic of tools that support BIM processes, I think it would be their ability to carry non-graphical attribute data on objects in the model. In other words, if you make a model which displays a set of columns, those columns should both look like columns (graphically) and know that they are semantically of a ‘column’ type. Typically, this means that they carry non-graphical classifications and attributes like type (“Corinthian”), height, weight, manufacturer, material, fire rating, &etc. arrayed in some pre-arranged schema like IFC.
Models with attributes can be used for analysis (cost, schedule, energy use, code compliance, etc.) that supports detailed design decision making… ultimately allowing the building to reach that fully constructible level of detail before construction begins.