A Brief History – and the Future – of BIM
Four Generations of BIM
The growth of BIM over the past decade has continued due to the benefits of using 3D virtual models to guide real-world processes. To understand where the technology is likely heading, it’s useful reviewing how the value of BIM has evolved. I trace the progress of BIM over the last 20 years in terms of key shifts and leaps in its capabilities over four major generations that we can call: BM, BM+I, BIM, and BI(m).
BIM has gradually grown from its origins in BM (Building Modeling) into BI (Building Information) with various combinations of model and data in between. A Building Information model can be viewed as a collection of BIM "atoms" of information in a context of project information. Over the generations, the composition of the atoms has changed but the essential nucleus of information is preserved. We are now entering the phase where BIM is valued as much for the information it can contribute beyond design and construction, and there are clear use scenarios, such as COBie where the information within the model is transferred even when the model itself is not.
1st Gen: BM
Today’s BIM movement originated from a simple premise: since buildings are three-dimensional, 3D models are a valuable tool for predicting aspects of the design and construction effort. The technology to create such models started to become a reality in the early-to-mid 1990s, as larger, digitally sophisticated firms began employing 3D modeling for various uses. We call this solely 3D-modeling effort (without data) Building Modeling or BM.
The value proposition of BM alone is to understand the relationships between purely physical, geometric components – beams and ducts or walls and stairs, for example. The “information” that exists in the BM model is simply spatial – where things start and stop, how they are arranged – which while valuable, is really just graphical information.
In the first pure BM phase, an atom of BIM was simply a 3D object. There was no other data, no opportunity to create schedules of components or arrange them on a timeline or count them for cost estimating. It was simply geometry. To do any of those other things, we would have to add data tags to the objects. This is largely what happened in the next stage of evolution: BM+I.
2nd Gen: BM+I
In the first advance, data tags were added to 3D objects. The geometry object dataset was simply expanded to contain fields of data that were attached to the geometry. The tags were added without much architectural “context," i.e., the objects did not understand that they were parts of a building. They were simply digital 3D objects with data fields. They could just as easily have been parts of a farm machinery model or an automobile 3D model.
However, for those computer-savvy users who could pluck the data from the 3D objects, arrange them into a spreadsheet and add the necessary context – often in their head – it would be possible to get some useful findings, like an equipment schedule.
The data transfer was not bi-directional, however. Once a design change was made, the data fields – again, without context – would be exported and manipulated again. Autodesk’s Architectural Desktop, Bentley TriForma, Graphisoft’s ArchiCAD and BricsCAD from the late ‘90s exemplify this approach where often quite comprehensive datasets could be attached to 3D objects like doors, walls, roofs, etc.
BM+I atoms, therefore, were 3D objects with data attached to them in a “pin-cushion” configuration. The “pins” containing object data were jabbed into the 3D objects but were not automatically related to each other.
3rd Gen: BIM
Before too long, a new breed of software – originating in the manufacturing world – was taking a totally new approach where 3D modeling was embedded in a construction context. Software like Parametric Corporation’s Pro-Engineer could emulate manufacturing processes. The CAD objects, however, were not the centerpiece of this software, but fabrication management and process simulation were. This bold new direction in digital design soon made its way to the AEC industry where similar software soon emerged – particularly Revit in 2000, which had a database at its core. In this new arrangement, the “information engine” was at the center of the software, and both graphical representations and schedules were driven by data contained in the engine.
In addition, data objects were clearly situated in an architectural context; walls for example, were “hardwired” to have certain behaviors, such as hosting doors and windows, gridlines and floor levels were understood as they exist in the construction world – as major determinants of building layout. Every component “knew” which floor level it belonged to, and all manner of architectural objects were capable of being scheduled.
At this stage, contextualized building-related data was born: atoms of 3D objects with embedded data floated in a further data context, what Victorian scientists might have called an “ether.” This heralded the arrival of BIM: BM linked to information management. This is roughly where we find ourselves today, with 3D objects in a context that also creates linkages among object data. But that is not where the evolution of BIM ends.
4th Gen: BI(m)
In this still nascent phase, which we could call BI(m), while our current focus is skewed towards the design and construction process – or data-input phases – we are quickly evolving into a new phase where information in the models get transferred downstream to an increasing cast of builders, owners and operations people.
The subset of data from the model is of greater importance than having the whole model, because once a project passes a certain point, the workflow emphasis shifts, and it becomes equally crucial to get that data out as the project enters the Bid, Construction and Operations phases. An atom of BI(M) is just information about 3D objects without the 3D object itself.
Obviously, it is not possible to jettison model geometry completely in the BI(m) stage, but it is information about the components rather than the 3D characteristics of the geometry that provides critical information for comprehensive tracking of construction projects. Some EYP clients, like Penn State, are using their models for operations and maintenance. As the technology continues to evolve, we expect to see more downstream uses... and perhaps a fifth generation of BIM.
- adapted from atomicBIM, originally published by AECbytes