What is BIM?

Building Information Modelling (BIM) is not new; it’s been around for over 30 years. The term relates to an entire process, rather than a product. It is often misunderstood simply as 3D CAD modelling but, while BIM does require software that is capable of 3D modelling, the key is implementing and sharing the information with the model. Collectively BIM represents the first truly global digital construction technology – since BIM issentially a way of thinking, it is possible regardless of project type and size.

BIM is based on the collaboration of designers working on the same 3D model from which all the documentation and data is extracted. It is used from the concept design phase, through to tender and construction. Even after project completion the BIM model can be used for asset management throughout the lifetime of the building, and as such involves all construction industry members.

Critically, BIM has been obligatory for publicly-procured projects since 2016. The implementation is driven and directed by the government, which expected to reduce capital expenditure on projects by 20% by applying this method. With government paving the way, it will soon become standard procedure, including in the private sector.

What are the key benefits?

BIM initially benefits designers, made possible by new modelling technologies. Applying a holistic method of designing provides better collaborative working, information, co-ordination and communication of project development. Other advantages include early cost certainty, predictable planning, better/earlier compliance checking and, because it helps support these benefits, it can reduce project risk and ultimately delivery costs.

Why is non-BIM practice inefficient?

Traditionally different activities during the design process are separated, each consultant working on different software and often different drawings. As such the communication can be inefficient. Here’s why: consultants are working on separate 2D drawings and use a 3D model that is not related to the 2D drawings. Every time a change occurs, all the drawings and the model need to be updated separately, including schedules and visuals. The chance of mistakes and clashes is high in this ‘old school’ environment, but surprisingly still common in many practices.

How does BIM work differently?

BIM produces a coordinated output based on a central 3D model. When changes are made in the central model, they are reflected in every output (views, drawings, and schedules). All the required data derives from one source, which means better integration between the different branches of design and specialists.

All BIM software has dynamic links to other software and so the changes made on the model can be reflected all the way through the project, even when consultants' models are on different platforms. It works with design tools that look and act like real construction elements, e.g. walls, door, windows etc. It also enables the integration of real objects based on manufacturers’ actual construction details. The fact that these elements have real and accurate physical properties makes everyone’s job easier. The designers can detect mistakes and clashes, the clients have a more accurate understanding of what will be built, and the contractor has confidence in the accuracy, reliability and coordination of the design information. Information can be populated into schedules and many of these processes can be automated, reducing the possibility of errors.

A new workflow

The model is developed within the same software from conceptual design through to the final design phase and after. As the design process goes on and the model evolves, it becomes possible to create:

  • Massing studies
  • Façade studies
  • Light studies
  • Design development
  • Value engineering exercises
  • CGI renders and movies
  • Planning and technical documentation
  • Details
  • Schedules
  • 3D fly-throughs for the client to sign-off

The whole team can work on the same model, even with colleagues who are based in different parts of the world.

The information model can be presented and even shared to clients and other members easily via BIMx – an application for tablets and smart-phones. This allows them to see the proposal in 3D before it is built and provides them with sections, plans and schedules, all from the same file.



In a BIM project we can differentiate between existing elements, new elements, and those to be demolished. This feature is crucial in a refurbishment project, where Lees Associates have unrivalled experience. With the BIM model we can even simulate construction and identify possible issues on site before the project even starts. Quantities can be extracted from the model that link directly to other software (typically working with cost management, known as ‘5D solutions’). Once construction is finished, facility managers can use the virtual model for handling and retrieving information, collaborating with architects and contractors for the lifetime of the building. A virtual building interface can be set up that links to mobile devices, thus allowing active maintenance and even automated servicing.


At Lees Associates we have been using BIM software for over 25 years. We work on ARCHICAD – a software package that was developed specifically for the architecture industry. Our clients enjoy the benefits of BIM whenever they work with us. Lees can offer BIM across many levels, from simple in-house project modelling up to full design team BIM integration. If you are interested in the possibilities of the BIM for your project or practice, feel free to contact our studio for a chat about the future.