What is Building Information Modelling

Sarah Lorek: Constructible

BIM model of a bridge built with BIM models only – no drawings

Across the world, BIM (Building Information Modeling) is a crucial and even mandated process to ensure the planning, design, and construction of buildings is highly efficient and collaborative. Read on to discover what BIM is, how BIM is used, and what BIM levels mean.

What Is BIM?

BIM is an acronym for Building Information Modelling or Building Information Management. It is a highly collaborative process that allows architects, engineers, real estate developers, contractors, manufacturers, and other construction professionals to plan, design, and construct a structure or building within one 3D model.

It can also span into the operation and management of buildings using data that owners have access to (hence the name Building Information Management). This data allows governments, municipalities, and property managers to make informed decisions based on information derived from the model— even after the building has been constructed.

From Blueprints to CAD to BIM

In the past, blueprints and drawings were used to express information about a particular building plan. This 2D approach made it very difficult to visualize dimensions and requirements. Next came CAD (Computer Aided Design), which helped drafters see the benefit of plans in a digital environment. Later on, CAD turned 3D, which brought more realistic visuals to blueprints. Now, BIM (Building Information Modeling) is the standard— but it is more than just a 3D model.

BIM Objects

BIM objects (components that make up a BIM model) are intelligent, have geometry, and store data. If any element is changed, BIM software updates the model to reflect that change. This allows the model to remain consistent and coordinated throughout the entire process so that structural engineers, architects, MEP engineers, designers, project managers, and contractors can work in a more collaborative environment.

Example of a BIM object – Optibal W6 ball valve with Actuator – downloaded from the manufacturer and used by plumbing engineers in their BIM models

The “I” in BIM

BIM, as a whole, refers to the process of having all parties involved in the construction and lifecycle management of built assets, working collaboratively and sharing data. However, the true power of BIM lives in the “I” (information). All of the information gathered— from conception to completion— isn’t just stored, it’s actionable.



The data can be used to improve accuracy, express design intent from the office to the field, improve knowledge transfer from stakeholder to stakeholder, reduce change orders and field coordination problems, and provide insight into existing buildings for renovation projects later on.

How Is BIM Information Shared?

This information in a BIM model is shared through a mutually accessible online space known as a common data environment (CDE), and the data collected is referred to as an ‘information model’. Information models can be used at all stages of a building’s life; from inception to operation— and even renovations and renewals.

Now that we’ve covered what BIM is and how it can be used, let’s move on to BIM levels.

What are BIM Levels?

Different levels of BIM can be achieved for various types of projects. Each level represents a different set of criteria that demonstrates a particular level of ‘maturity.’ BIM levels start with 0 and go to 4D, 5D, and even 6D BIM. The purpose of these levels is to gauge how effectively, or how much information is being shared and managed throughout the entire process.

So what does each level involve, and how can you identify the level at which you’re working? Below are brief descriptions of the first three levels and an explanation of what criteria is involved at each stage.

Level 0 BIM: Paper-based drawings + zero collaboration

Level 0 BIM refers to not operating collaboratively at all. If you’re using 2D CAD and working with drawings and/or digital prints, you can safely say you’re at level 0. Today, most of the industry is working above this level, although not every professional in the industry has sufficient BIM training and some projects do not include the use of BIM in contract specifications.

Level 1 BIM: 2D construction drawings + some 3D modelling

Using 3D CAD for concept work, but 2D for drafting production information and other documentation, probably means you’re working Level 1 BIM. At this level, CAD standards are managed to the standard of BS 1192:2007, and electronic sharing of data carried out from a common data environment (CDE) usually managed by the contractor. Many firms are at Level 1 BIM, which doesn’t involve much collaboration, and each stakeholder publishes and manages their own data.

Level 2 BIM: Teams work on their own 3D models

Level 2 BIM begins to add in a collaborative environment. BIM Level 2 was actually made a mandatory requirement in April of 2016 on all publicly tendered projects in the UK. France followed shortly after with their own mandate in 2017.

At level 2, all team members use 3D CAD models but sometimes not in the same model. However, the way in which stakeholders exchange information differentiates it from other levels. Information about the design of a built environment is shared through a common file format. When firms combine this with their own data, they save time, reduce costs, and eliminate the need for rework. Since data is shared this way, the CAD software must be capable of exporting to a common file format, such as IFC (Industry Foundation Class) or COBie (Construction Operations Building Information Exchange).

Level 3 BIM: Teams work with a shared 3D model

BIM level 3 is even more collaborative. Instead of each team member working in their own 3D model, Level 3 means that everyone uses a single, shared project model. The model exists in a ‘central’ environment and can be accessed and modified by everyone. This is called Open BIM, meaning that another layer of protection is added against clashes, adding value to the project at every stage.

Benefits of Level 3 BIM include:

  • Better 3D visualization of the entire project
  • Easy collaboration between multiple teams and trades
  • Simplified communication and understanding of design intention
  • Reduced rework and revisions at every stage of the project

Levels 4, 5, and 6 BIM: Adding in scheduling, cost, & sustainability information

BIM level 4 brings a new element into the information model: time. This information includes scheduling data that helps outline how much time each phase of the project will take or sequencing of various components.

Viewing a 5D BIM model within a common data environment to run a structure sequencing breakdown based on pour numbers

Level 5 BIM adds cost estimations, budget analysis, and budget tracking to the information model. When working at this level of BIM, project owners can track and determine what costs will be incurred during the length of the project.

Level 6 BIM information is useful for calculating the energy consumption of a building before it’s built. This ensures that designers take into account more than just the upfront costs of an asset. Level 6 BIM ensures accurate predictions of energy consumption requirements and empowers stakeholders to build structures that are energy efficient and sustainable.

Benefits of Levels 4, 5, and 6 BIM:

  • More efficient site planning and scheduling
  • More efficient hand-offs between steps in the construction stage
  • Real-time cost visualization
  • Simplified cost analysis
  • Reduced energy consumption in the long run
  • Better operational management of the building or structure after handover

The Future of BIM

Because of the clear benefits, BIM is here to stay.

It has defined goals and objectives that are clearly beneficial to all those who work their way through the levels. Undoubtedly, the future of construction will be even more highly collaborative and digital. As BIM becomes increasingly more sophisticated, 4D, 5D, and even 6D BIM will start to play a part in the process.

More and more, stakeholders are walking through BIM models using augmented and virtual reality. This application can help contractors and manufacturers with clash detection and training, architects to sell their designs, and owners to “see” into their structures and make better decisions for maintenance and retrofitting.

Furthermore, around the globe, there is an attempt to reduce waste in construction. Much of this  is attributed to supply chain inefficiencies, clashes, and reworking. By working collaboratively in a BIM environment, all of this becomes much less likely, setting the stage for a better tomorrow.


This article was published with permission from Constructible.

Posted in General.

Leave a Reply

Your email address will not be published. Required fields are marked *