Technology & Innovation

Defining the dimensions of BIM

3D. 4D. 5D. And, yes, even 6D.

Walk into a room where a discussion of building information modeling (BIM) is happening and you’re sure to hear these “Ds” peppered throughout the conversation. These dimensions make up the lingo defining BIM’s main processes. Together they aim to improve decision-making and problem-solving throughout the building lifecycle.

So, if you were quizzed on the meaning of these terms today, would you score high, or low? Many professionals in the construction industry wouldn’t have a clue beyond the 3D aspect of BIM. Yet, understanding these processes will be key as BIM continues to make its way into the construction industry.  Let’s take a closer look:


At the core of building information modeling is a 3D representation of a building or other built environment. A 3D model helps you see things that are not apparent on 2D drawings such as whether a wall is slanted. The intelligence built into the model also can identify constructability issues. For example, the model can detect pipework running through a steel beam. Because of its visualization capabilities, including animation and walk through, a 3D model is often used to better communicate a project’s scope to building teams and owners.


Apply timelines to a model and you have 4D BIM. This allows construction planners to run simulations to assess how proposed design features will impact the construction schedule and workflow. With 4D BIM, planners can determine appropriate resource scheduling, identify potential bottlenecks, develop phasing plans, communicate and track milestones, and find opportunities to improve the schedule overall.


Cost estimating is the next process layer added to the BIM model. Known as 5D BIM, it allows estimators to quickly provide the cost impact of different design and schedule scenarios. Using 5D BIM tools and methods, estimators can explore cost saving strategies and conduct cost risk analysis in much less time.


BIM doesn’t stop once construction ends. With 6D BIM, facilities managers use as-built information gathered from the design and construction process—as well as updated details from ongoing maintenance—to support decision making throughout a facility’s operations cycle. Use of 6D BIM can lower maintenance and renovation cost as well as lessen disruption to building occupants.

7D and beyond?

Mentions of 7D and 8D BIM are also beginning to surface. As of yet, however, there isn’t agreement on exactly what BIM processes these dimensions will help define. One thing is certain though: BIM still has room to grow.

Getting your arms around all the aspects of BIM can be a bit daunting. The dimensions I’ve mentioned are designed to clarify the ever-evolving facets of BIM. I hope this post gives you a better idea of how you can incorporate BIM into your construction process.