BIM: A Definition

In the construction industry, Building Information Modelling (BIM) is about developing and operating buildings using digital data that all relevant stakeholders have access to.

Rather than describing the technology used, or just the 3D model that accounts for the ‘M’ of the acronym, BIM refers to the process of all parties involved in the construction and lifecycle management of built assets working collaboratively and sharing pertinent information. 

This information is shared through a mutually accessible online space known as a common data environment (CDE). 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 right through to operation and even refurbishment and renewal.

BIM operates at different levels. Each level describes a different set of criteria which, when met, demonstrate a particular level of ‘BIM maturity’. These levels begin with 0 and go up to 4D and beyond. They are used to gauge how effectively information is being shared and managed throughout the supply chain.

What isn’t always immediately clear is what each level involves and it can be confusing to identify at which level your working and how you can develop your BIM maturity. Here is a brief guide to the first three levels and an explanation of what criteria are involved at each stage. 


The different levels of BIM


Level 0 BIM

Level 0 BIM

If you’re working at Level 0, you will not be operating collaboratively at all. If you’re using 2D CAD and working with drawings and/or digital prints then you’re at level 0. These days, most of the industry are working above this level, although there is still some unease among those who are yet to fully understand the benefits of moving up the BIM ladder.

Level 1 BIM

Level 1 BIM

If you use 3D CAD for concept work but 2D for drafting production information and other documentation then it’s likely you’re working at Level 1. At this level, CAD standards are managed to BS 1192:2007 and electronic sharing of data is carried out from a common data environment (CDE) usually managed by the contractor. A great many businesses are working at this level where there typically isn’t any collaboration and each stakeholder publishes and maintains its own data.

Level 2 BIM

Level 2 BIM

Level 2 sees the emergence of working collaboratively. Since April 2016, it’s also been a mandatory requirement on all publically tendered projects in the UK.  At level 2, everyone uses 3D CAD models but, typically, not the same, single, shared model. However, the way stakeholders exchange information is key to level 2. Information about the design of a built-asset is shared through a common file format. When businesses combine this with their own data of their own they can carry out checks that save time and money of manpower and reworking. Because of the way data is shared, 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

Level 3 BIM

The UK Government is committed to Level 3 being prerequisite for all projects in the future. Many people regard it as a BIM panacea. Instead of each party working on their own 3D model, Level 3 sees everyone using a single, shared project model. The model sits in a ‘central’ place and can be accessed and modified by everyone. This is what is referred to as Open BIM. This means that another layer of protection is added against clashes, adding value to the project at every stage.

Globally, there is a drive to reduce waste in construction. Much of the wastage in the sector currently is attributed to supply chain inefficiencies, aborted work, clashes and reworking. Working collaboratively in a BIM environment makes all of these considerably less likely.

Hailed as the industry’s saving grace, it’s certain BIM is set to stay. It has defined goals and objectives that are clearly of benefit to all those who work their way through the levels. Undoubtedly, the future of construction is collaborative and digital. As BIM becomes increasingly more sophisticated, 4D, 5D and even 6D BIM will start to play a part in the process.

For now, however, it’s enough for most to battle jargon and tech talk in a bid to understand levels 0-3.


BIM Digest


BIM Digest: Volume One
Your guide to the current topics in the world of BIM

To read more musings on the current hot topics in BIM (including sensible contributions from industry experts), download our free eBook; BIM Digest (volume 1).


Download BIM Digest: Volume One

  Downloaded over 1,000 times



Other blog posts you might like


What do people mean by "BIM-to-Field"?

BIM-to-Field is the process of taking the accurate digital data in an information model and using it to inform accurate construction, operations or maintenance out on site. Tools such as the Robotic Total Station (RTS) by Trimble MEP enable you to import model data to a hand-held tablet device in the field.


BIM: Information Overload!

BIM is accelerating the march towards creating and holding increasing levels of detail and therefore data, our ability to produce data is starting to outstrip efforts to successfully process, interpret, organise and communicate it such that it then becomes information.