What is BIM,

An Article
Jason Howden

Jason Howden is an expert on a new digital technology known as Building Information Modelling (BIM). Jason is the Technical BIM Manager at architecture firm Warren and Mahoney where he has made significant contributions to the Christchurch rebuild in New Zealand. He will also be a guest speaker at the inaugural Asian Revit Technology Conference in Singapore 10-12 September 2015. 

One data platform,
one common language,
one 3D Design.

Building Information Modelling, better known as BIM, is the future of the construction industry. In basic terms, a building is digitally designed from the ground up into a 3D model of the building and information about how the many parts of the building all fit together.

The major players including designers, architects, engineers and contractors, work together using one data platform, one common design language, to make one cohesive 3D design of a building. All the information is able to be shared and the design of the project can be worked on simultaneously and in real time.

Having a complete 3D digital model has enabled many technological advances to be made in the construction industry and has changed the way we build for the better.

For example, many of the basic building blocks across buildings are the same even if the way those building blocks are put together in each building are different. Think of it like gigantic virtual Lego pieces; at the heart of our BIM system, we have a series of very common Lego blocks which form the core of the design. Then, like Lego, we also have sets of specialist blocks we use with the common blocks to design and build, say a hospital, office tower, airport or prison.

A hospital set is healthcare focused so elements like light and air quality will have priority; a prison set will focus on security and safety; an airport set will have inbuilt systems for retail opportunities and information areas.

And it’s not just the design process that has been digitised; BIM has also changed the way that contractors construct buildings. Builders on site can use a tablet computer to view the BIM plan as a digital overlay on top of what they are physically seeing, similar to ‘augmented reality’ but with a construction focus.

A laser grid that is accurate down to the millimetre is projected on the area being worked on and the tablet computer is able to pick it up and use it to show the BIM model overlaid on a live picture feed so that workers can see exactly what the project is supposed to look like and work precisely to plan.

For instance, we were recently working on a project which required fixtures on a concrete wall and ceiling. Traditionally those fixtures would require a lot of work drilling into the concrete, but because we were able to visualise the project using BIM tech, the building contractor was able to install them in place before the concrete was poured with confidence that they had been placed accurately. Having a comprehensive 3D plan that is geospatially correct makes following the plan much easier, and can reduce installation time in this way by up to 50%.

With BIM, there are better options to pre-manufacture. When you have certainty on how the building is going to fit together digitally, you can manufacture complex parts of the building in a controlled factory environment. When the entire piece can be assembled in a factory, out of rain, sleet, hail, then brought to site and screwed into place, that’s a good thing for the project’s efficiency.

Using BIM also helps businesses get a return on their capital by allowing them to monitor and assess the performance of their facility from energy usage through to operational efficiency before it is built. For every $1 that’s spent on design, another $10 is spent on construction, and another $100 is spent on the running of the project over its lifetime. So, if you can be more efficient in the operations of a building, you’ve done something magical. BIM is a long-term investment, not just a short term fix.

The first working example of this in our part of the world will be the Sydney Opera house. A comprehensive BIM model is being developed to track everything from bookings to mechanical equipment. A lot of people underestimate the componentry hidden behind the walls and ceilings that go into making a theatre facility work. The servicing of machinery is a big task and traditionally a paper and email based system has been responsible for thousands of individual parts. It’s a mental mind field making sure that each has been serviced, isn’t faulty, and none of the components need replacing. The last thing you want is for people to turn up on show night and find that the AC is not working properly because a filter has not been replaced. Even the roof tiles are bar coded and scanned so that if anything happens, they should be able to replace any tile with one of the right size as easily as a light bulb.

Using computational models to monitor energy efficiency has been around for a while amongst technical specialists, but BIM has started to socialise these things with the lay person so that they can understand it by visualising it as a 3D model. For example, if the Sydney Opera House were to install new air conditioning they would use computational fluid thermodynamics to choose the optimal position, and they can use the BIM model to visualise air tunnels in 3D and see that air flows will function as intended.

Building Services BIM Christchurch Acute Services Building, including HVAC, Electrical, Plumbing and Drainage design models

Combined Christchurch Acute Services Building BIM, including Architecture, Structure and Building Services design models

01 + 02

What businesses need to know is that the world is changing. The way contracts and projects are being procured is changing. The construction efficiencies that can come from BIM are exponential. For building and design, it’s really adapt or fold. It’s like Kodak – they were making money for hundreds of years in camera and film, then digital technology came along, and they didn’t embrace it, they didn’t adapt. Now they’re gone.

In New Zealand, the Christchurch Rebuild has been a catalyst for the adoption of BIM more widely within the construction industry. Warren and Mahoney projects in the rebuild that have made use of BIM include:

Canterbury Arts Centre

As a result of the 2010 and 2011 Canterbury earthquakes, 22 of the 23 heritage buildings at the Arts Centre sustained significant damage and were subsequently deemed unsafe. The restoration and rebuild of the Arts Centre is taking place in phases due to its complexity as one of the largest heritage restoration projects in the world. Laser scanners were used to assist the capture and creation of a digital 3D model of the original buildings, these models were later used as background to the 3D design documentation. Physical 3D models were also printed from the digital models.


Short for Canterbury Engineering the Future is a refurbishment project at the University of Canterbury due to be finished in 2017. The existing buildings will be stripped back to their structural frame, before being recreated. Instead of the present ‘defensive’ layout, with fixed barriers between departments, the new design will be more fluid with a central connecting hub that will link the departments and provide both formal and informal shared teaching space supportive of modern teaching methods. 3D design documentation was prepared using BIM authoring software allowing for enhanced design visualisation throughout the design process.


King Edward Barracks is a $150 million plus office and apartment complex around a central square that will be built to replace Christchurch’s old police headquarters. Up to 1500 workers will eventually occupy the site, including 350 public servants. With up to four commercial buildings, walkways, car park building and row of apartments, the development will take up the entire riverside block between Hereford, Cashel and Montreal Streets and Cambridge Terrace. 3D design documentation was prepared using BIM authoring software allowing for enhanced design visualisation throughout the design process.


The new building, to be known as The PwC Centre is centrally positioned near to the developing business centre, retail and justice precincts, as well as to transport links. The building is lightweight but strong and designed to 130% of the current building code (IL3). With a high level of energy efficiency and a distinctive façade that embraces its surroundings, the PwC Centre will be a landmark. 3D design documentation was prepared using BIM authoring software allowing for enhanced design visualisation throughout the design process.

Christchurch Justice and Emergency Services Precinct 

An estimated 2000 people will work in or use the 42,000m² precinct daily. At the peak of construction 500 people will work on the project. Warren and Mahoney has used BIM technologies to assist the Fletcher construction team onsite to check Bill of Material and Schedule of Quantities, to digitally set out building elements, and to test prototype building elements for manufacture in the BIM environment.

Christchurch Hospital Acute Services Unit

Major construction will begin later in the year on this 62,000m² project. The design has been worked on by Katoa – a consortium of W&M, Chow:Hill and Thinc  Health. 3D design documentation was prepared using BIM authoring software allowing for enhanced visualisation throughout the process.

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