Glyn Shawcross, engineering and design director of engineering solutions provider Boulting Ltd explains how future advances in BIM will continue to enhance control for contractors and clients

The Crossrail project, also known as the Elizabeth line of the London Underground, is the largest construction project currently underway in Europe. Building Information Modelling (BIM) is already being used to improve efficiency throughout the project life cycle of the 73-mile railway line, and the value added by BIM will increase as technology advances.

BIM, an evolution of 3D computer-aided design (CAD), is a collaborative way of working that facilitates the efficient design, delivery and maintenance of buildings throughout their entire lifecycle. It provides an integrated approach for design and coordination of complex components and systems, cutting out waste and reducing errors through the decision-making process.

One of the newest iterations of 3D modelling, BIM provides a complete visualisation of the entire project. Using BIM, all attributes can be added to one federated model linking/combining all different discipline models with clashes identified and reworked at an early, pre-construction, stage.

There are several levels of BIM, each more advanced than the next, and each level can be carried out in a number of dimensions. Each level changes the method of working, while every dimension adds a new feature or benefit to the process.


At level zero, two dimensional BIM is the simplest and can simply be a 2D flat computer-aided design (CAD) drawing. Increasing to three dimensions, level one and two BIM involve 3D drawings, with level two requiring a level of collaboration.

Level 2 BIM is perhaps the most commonly used level, in part because it is the current minimum standard required by the UK Government for its public-sector work, a standard introduced in 2016.

Gold standard construction

Now we have reached the minimum standard of BIM, where a shared three-dimensional model is used for collaboration, we can begin looking to the future.

Staying in three dimensions, BIM Level 3 is the current gold standard that the industry is working towards. Its 3D single model is shared across all collaborators. This model contains all the functional information needed about each building asset, throughout the design, build and maintenance stages.

The 3D model is crucial to all levels of BIM above Level zero. When working on an existing project, such as a retrofit or refurbishment, it can be very difficult and time-consuming to generate an accurate BIM model.

Instead, many teams are choosing to employ 3D laser point cloud scanning, which can very quickly provide a highly accurate 3D map. This map can then be integrated into BIM software such as Autodesk Revit and used as a starting point to be combined with attributes for new components.

In addition to the three-dimensional model, other dimensions can be added to the BIM visualisation: time management (4D), budget calculation (5D) and facilities management (6D).

Four-dimensional BIM

The depth of data included in the BIM attributes associated with a component means it is possible to use the tool to manage time. Time data can be included in each attribute, including its lead time, installation time and even the sequence in which components must be installed.

This allows planners to develop an accurate project programme. The accumulation of data linked to a visual representation of components makes it easy to understand and query project information, as well as demonstrating to clients how construction will develop over time.

This programme is one way in which work can be managed to ensure it is safe, logical and efficiently sequenced before it begins. Through the virtual representation, planners can assess how assets will come together before the ground is broken, allowing for early-stage feedback and avoiding wasteful and costly on-site changes.

In addition, the visual timeline can be presented to clients, helping to explain plans and ensure expectations are communicated in a clear manner.

Five-dimensional BIM

5D BIM builds upon the visual time representation. By combining assets and their schedule data with cost-related information, 5D BIM can allow the client to visualise the cost of a project over time and manage the cash flow throughout a project.  In addition to not allowing for any unwelcome price changes, 5D BIM can improve and plan overall management and delivery of projects of any size and complexity.

This is particularly important as projects become more complicated, perhaps with additional modules, extensions or additions to the original structure.

“The quality of your cost estimate is directly linked to the quality of the data produced by the rest of the project team,” .

“In the BIM process, cost managers are engaged right from the outset and are an equal player in the project team,” Fred Mills, co-founder of The BIM.

Six-dimensional BIM

Unlike 4D and 5D BIM, which are possible at any level above Level two, six-dimensional BIM can only be carried out at Level three. This is because six dimensional BIM uses a cloud-based model, allowing it to incorporate facilities and plant management, including component information, such as product data and details. The cloud-based system means contractors working on different aspects of the building can each access the system throughout the facility’s life cycle.

6D BIM functions primarily by linking attribute data together to support facilities management. For example, details about manufacturers, install dates, maintenance schedules and data including operating temperatures and lifespan can all be included.

The use of 6D BIM can aid facilities managers, maintenance engineers and the client when working together to produce an effective maintenance schedule. From a planned predictive maintenance (PPM) schedule of machinery within a facility, to routine maintenance such as light refurbishment and replacement, 6D BIM can consolidate attribute information. Bringing all data into one plan is the best way of producing an efficient and effective maintenance schedule throughout the facilities’ lifecycle.

As BIM becomes more advanced, the value it can add to projects continues to increase. In addition to providing a visual representation of a project, it is becoming an essential collaborative tool, which is invaluable to cost managers, contractors, designers, facilities managers and the client alike.

Although BIM is already adding value to many large-scale engineering projects such as Crossrail, as the technology advances it will become even more valuable and essential. This will mean we see BIM used across more projects, ranging from large-scale public-sector projects where BIM is mandated, to smaller independent builds and refurbishments.


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