Building Information Modeling is under heavy pressure nowadays, with the BIM world currently shifting from the reality of the construction sector to a “parallel” conceptual world that does not necessarily reflect real engineering, construction and operation of buildings.

There are several weak points that must change to bring back to reality this challenging information system, especially the dividing of BIM into seven  "dimensions." The dimensions threaten to introduce too many vertical silos that fail to reflect the multidisciplinary ideas that shape the building process. These vertical silos make it more difficult to introduce innovations such as digital twins and real-time building monitoring.


The first weakness is in the seven BIM dimensions, which are currently a plan view (2D), geometrical shape (3D), scheduling (4D), estimating (5D), sustainability (6D) and facility management (7D). Although these dimensions are often thought in separate and vertical ways, the construction sector is not neatly divided to fit them. Construction and building management is most often thought of as design, construction and management. This is the reality to which BIM has to return.

BIM dimensions have to be considered on a multidisciplinary basis in each of the three basic stages. Since costs are not separated from scheduling, why do we have a 4D and 5D? And sustainability clearly involves 3D modeling and facility management.


Next, let's think about design dimensions, such as sustainability. In several countries, there are national or international programs with standard parameters to monitor sustainability or general energy consumption and a schedule of parameters which requires static and dynamic simulation, analysis and reports. Each of these parameters is also linked with cost and monitoring.

It makes little sense to have a dimension linked only to sustainability if sustainability isn’t an aspect of design evaluation for both new and existing buildings that may need renovation. Thin of it this way: Why don't we have a dimension for structural calculation or fire safety strategy? Because structural calculations and fire safety strategy are aspects of the design! Each of these aspects is inter-linked and has to be linked with the design stage which collects and produces the information needed in the monitoring and facility management stages.

So, to our way of thinking, sustainability is not a dimension but a design aspect like every other discipline.


Our third major point regards building monitoring and facility management, the longest and most expensive phase of a building that involves the whole life cycle and one that accounts for 70% of the overall costs. Facility management must be conceived and planned in the design phase and be supported by building monitoring. Choices made during design must be evaluated during the building's life, and design choices and actual construction will yield data that helps monitoring and maintaining the building during its lifetime.

So all that data can't come from the seventh dimension alone, unlinked to other aspect of the building's creation. Every  digital analyses of the building's design and construction are linked with the facility stage, and if it isn't done at first, it will be needed in the near future.

The Real-Time Dimension

Today, the average car has sensors which constantly monitor its performance. Real-time building monitoring has to be considered in the BIM digital world. What we now call the facility dimension of BIM shall become, in the near future, the real-time dimension, where the stream of information that goes to and from the building becomes the building's digital twin.


There are already some examples where digital twins and real-time BIM are used successfully, such as in sensor-filled tunnels and bridges. From bridge monitors, the managers get daily reports about structural stresses and special messages with information about critical situations. The same could be done in highrises, museums and hospitals. Facility strategies, including maintenance, will have to be considered in the design phase. Monitoring will  reduce costs and time needed for extraordinary maintenance. 

Reducing the number of BIM dimensions to reflect the actual construction process will provide a deeper, clearer and more realistic link with the construction sector. Assigning the right dimension to the right stage(s) of construction and building operations will be important. While implementing BIM in the ways we recommend may consume more resources initially, the benefits will allow a more efficient use of those finite resources.

Nicola Ianeselli, BIM lead for BEC Industries; Riccordo Coccoluto, BIM coordinator at Ricardo Bofill Taller de Arquitectura; and Massimo Purin, BIM expert for Italy’s LFAGroup and Sebastiano Fabrizio Muscolino, BIM Expert for eFM spa., can be reached at