What is BIM, anyway?

[Sticky] What is BIM, anyway?


Is it just me, or do some professionals in the industry distrust the term BIM (Building Information Modelling)?

Have you come across any misunderstanding about the meaning of BIM? If so, how did you handle it?


Hi Alex,

BIM is confusing, this form of information is currently used for the public sector and it is supposed to be a collaboration of all the design team to share the information on one 'model'. This incorporates all the information from the architect, structural engineers, M&E engineers, lighting designers, interior designers etc all on one drawing.  The drawing includes all the specifications (NBS), products used etc.  This is to form a more cohesive design and to make the process quicker.

I'm currently on BIM level two (you can check the different levels of BIM on the NBS website), this is where information is exchanged to all parties and is co-ordinated by the lead architect. I work on private projects that are at a residential level and the information is manageable.  I normally check all the work done by others to make sure there are no discrepancies and any changes to design or structure is relayed to all so they can amend their drawings if needed.

I hope that clears it up for you. BIM also uses Revit, so that could be another factor to consider.  I have basic knowledge of Revit so would need to learn it to a higher standard if I want to work on more public projects.


A Scott

I agree, NBS is a reliable information source for BIM. https://www.thenbs.com/knowledge/what-is-building-information-modelling-bim

BIM or Building Information Modelling is a process for creating and managing information on a construction project across the project lifecycle. One of the key outputs of this process is the Building Information Model, the digital description of every aspect of the built asset. This model draws on information assembled collaboratively and updated at key stages of a project. Creating a digital Building Information Model enables those who interact with the building to optimize their actions, resulting in a greater whole life value for the asset.

Through BIM, the UK construction industry is undergoing its very own digital revolution. BIM is a way of working. BIM is information modelling and information management in a team environment, all team members should be working to the same standards as one another. BIM creates value from the combined efforts of people, process and technology.


NBS made also a video for a project built through the BIM process.

YouTube video:

(please log in to see content)


As Naz pointed out BIM is also about maturity levels (or BIM levels) https://www.thenbs.com/knowledge/bim-levels-explained


The concept of ‘BIM Levels’ (and ‘BIM Level 2 compliance’) has become the ‘accepted’ definition of what criteria are required to be deemed BIM-compliant, by seeing the adoption process as the next steps in a journey that has taken the industry from the drawing board to the computer and, ultimately, into the digital age.

The government has recognised that the process of moving the construction industry to ‘full’ collaborative working will be progressive, with distinct and recognisable milestones being defined within that process, in the form of ‘levels’. These have been defined within a range from 0 to 3, and, whilst there is some debate about the exact meaning of each level, the broad concept is as follows:


Level 0 BIM

In its simplest form, level 0 effectively means no collaboration. 2D CAD drafting only is utilised, mainly for Production Information (RIBA Plan of Work 2013 stage 4). Output and distribution is via paper or electronic prints, or a mixture of both. The majority of the industry is already well ahead of this now (source: NBS National BIM Report 2017).


Level 1 BIM

This typically comprises a mixture of 3D CAD for concept work, and 2D for drafting of statutory approval documentation and Production Information. CAD standards are managed to BS 1192:2007, and electronic sharing of data is carried out from a common data environment (CDE), often managed by the contractor.

To achieve Level 1 BIM, the Scottish Futures Trust states you should achieve the following:

  • Roles and responsibilities should be agreed upon
  • Naming conventions should be adopted
  • Arrangements should be put in place to create and maintain the project specific codes and project spatial co-ordination
  • A "Common Data Environment" (CDE) for example a project extranet or electronic document management system (EDMS) should be adopted, to allow information to be shared between all members of the project team
  • A suitable information hierarchy should be agreed which supports the concepts of the CDE and the document repository.


Level 2 BIM

Level 2 BIM is distinguished by collaborative working, and requires "an information exchange process which is specific to that project and coordinated between various systems and project participants" (Source: Scottish Futures Trust).

Any CAD software that each party uses must be capable of exporting to one of the common file formats such as IFC (Industry Foundation Class) or COBie (Construction Operations Building Information Exchange). This is the method of working that has been set as a minimum target by the UK government for all work on public-sector work.

For more information on working to BIM Level 2, see the following guide developed by NBS and BSI:  https://bim-level2.org/en/about/


Level 3 BIM

Level 3 has not yet been fully defined, however the vision for this is outlined in the UK Government's Level 3 Strategic Plan. Within this plan, they set out the following 'key measures' to be secured with further funding:

  • The creation of a set of new, international ‘Open Data’ standards which would pave the way for easy sharing of data across the entire market
  • The establishment of a new contractual framework for projects which have been procured with BIM to ensure consistency, avoid confusion and encourage, open, collaborative working.
  • The creation of a cultural environment which is co-operative, seeks to learn and share
  • Training the public sector client in the use of BIM techniques such as, data requirements, operational methods and contractual processes
  • Driving domestic and international growth and jobs in technology and construction.


With regards to @alex's question, I think it is probably more a matter of the old dog/new tricks problem. People tend to stick with what works for them, especially if it is smaller jobs. Why invest in considerable technology and training when the vast majority of your revenue comes from extension and residential projects?

With that said, I do not discount the confusion that you probably speak of. I had an interesting article saved from Construction Industry. Link here: https://www.constructionnews.co.uk/contractors/lendlease/bim-is-it-holding-back-digital-construction-16-07-2018/


In 2011, the government announced that all central government projects must be BIM (building information modelling) Level 2 compliant, with it being mandated from April 2016. But seven years on from that announcement, many in the industry remain unsure of what BIM is – and what firms need to do in order to be compliant, as revealed in a survey by specification services provider NBS.

Its national BIM survey for 2018 looked into whether the government’s mandate had been successful and whether the industry was increasing its adoption. The findings revealed that only 58 per cent of industry respondents were confident in their BIM knowledge and capability. Around 41 per cent said they were still unclear on what they needed to do to comply with the mandate.

While different interpretations persist, contractors could find themselves in legal hot water. This confusion about BIM is presenting difficulties for the industry, which begs the question: has the mandate proved more of a hindrance than a help?

Why the confusion?

Mr Ingram says the concept of BIM may be too complex for people working in non-technical positions to understand, which is the main reason behind the confusion over what exactly BIM is.

He says engineers, designers and architects within companies are the ones pushing the agenda. But outside of these roles, BIM remains unclear to most.

It is often misunderstood as being a 3D design software tool, when in fact it is more like an initiative to move the industry into a “data-driven world from a document-driven world,” Mr Ingram says. “There’s some really smart technology being used, but if you speak to a commercial director or finance director, it’s kind of lost on them and they don’t know what it is. That’s part of the problem […] BIM has been made too complicated.”


On top of that some firms in the industry oversell their actual capability to being BIM-compliant, in an obvious attempt to get more business. The problem is serious enough that a term was coined for it ("BIM Wash") https://www.bimthinkspace.com/2011/06/episode-16-understanding-bim-wash.html

Of course this adds to the overall hesitation.


But the intent is noble: provide technology and process to enhance collaboration and reduce rework.

And that is what BIM is meant to do.