Space the final frontier?

This is the promised land of 3D modelling. It has already been in use in other industries, such as the petrochemical industry, for more than a decade and is slowly but surely finding its way into construction.

Revit Technology, a US-based software manufacturer, launched its web-based 3D system in the UK in September (see opposite) and among those to sign up is engineer the Waterman Partnership. Pressure from clients drove Waterman to look for a 3D modelling system, says Lee Barnard, CAD manager at Waterman. "Clients have been asking for a 3D modelling system for a long time. We have been impressed by what we have seen of Revit so far. We are training our staff to use it at present, and plan to really start using the package in December."

Other construction companies have been developing their own 3D systems. Contractor Laing has been looking at the use of 3D modelling since the 1970s, but it is only in the past three years that the technology and expertise has really moved things forward. In 1998, Endeavour House at Stansted Airport was used as an Egan demonstration project and Laing received funding from the DETR to research the use of 3D modelling on the scheme. "We demonstrated savings of 10% could be made on that project using modelling," says Mervyn Richards, Laing's CAD manager. "And we came to it late, so those savings were made off the back end. There is the potential for 20% savings if modelling is used early enough."

As well as cutting down on administration costs by eliminating the need for sending drawings back and forth, 3D modelling also saved Laing money by identifying potential problems before work started on site. It estimates £600 000 alone was saved this way.

Laing is currently using 3D modelling on a £128m project to redevelop Basingstoke town centre for Grosvenor Holdings, its most ambitious and comprehensive use of modelling to date. "With the model at Basingstoke, we are working towards zero defect construction information, and virtual construction," says Richards.

Ensuring zero defects

One way of ensuring zero defects is clash detection. This is where the model alerts you to any design clashes in the structure of the building. But advances in object-based technology mean even clashes inside the building can be identified. "Clash detection is a big benefit of 3D modelling," says Richards. "But what we are finding increasingly useful is proximity checking, which detects how close an object is to another, and won't put two objects in one space. For example, you can only put a window in a wall if you make a hole for it."

And 3D modelling is helpful not only as part of the construction process. It can also be sold as a benefit to the client after the project is complete. "We build and manage the model for the client during construction, but we can pass it on to them once the job is finished and it can be used for maintenance," says Richards.

Managing costs

Building and managing a 3D model is not cheap, but costs are falling all the time, according to Richards. "Two years ago we built and managed a model for £85 000 on the £6m Endeavour House job. The model on the Basingstoke job has cost the same, but it is 16 times bigger and the project value is much greater, at £128m."

Engineer Whitby Bird and Partners has been developing its own 3D modelling system since 1994, inspired by the use of modelling in the steelwork industry.

Whitby Bird produces a 3D steelwork model, which is recorded on to a CD, and sent directly to the steelwork manufacturer so that fabrication can start. The manufacturer can then add data to the model, which makes life easier on site.

For instance, tags can be added to the drawings, which schedule loads, so the steelwork is loaded on to the lorries in the sequence they will be needed on site.

For its work on the Toyata headquarters in Epsom in 1998, Whitby Bird estimated the number of requests for information was cut by 20% because of the use of 3D modelling. "Using 3D modelling cuts down on the paper loop," says Richard McWilliams, an associate with Whitby Bird, who has been developing the system. "A lot of queries that might otherwise have been asked are already answered by using a 3D model. Each query costs at least one hour – someone estimated it costs the project as much as £1000 per query."

Supply chain management

3D modelling can also help with supply chain management, by improving communication and relationships. "If there aren't any queries," says McWilliams, "you don't have to constantly send bits of paper back and forth, which is time consuming and can create misunderstandings. It is also very low risk to send out a 3D model to the fabricators, if they send us back a detailed version, so there is no confusion over changes that need to be made. Also, many potential problems will already have been identified."

For those still attached to 2D, such as subcontractors on site, the model can be cut into sections and 2D drawings taken from it, but McWilliams says this is not really necessary once you have confidence in the use of the 3D version. "We originally used 2D drawings as backup for the 3D model, but we found it was hampering the process as they quickly became out of date. It was easier to constantly update the model."

As well as being a useful maintenance tool for a client once the project is complete, a 3D model can also help to give an impression before it begins. Management consultant Gleeds has had a good response from clients to its use of 3D modelling. "We produced a 3D model for Scottish & Newcastle Breweries' headquarters building, and we got a very enthusiastic response," says Graham Robinson, head of management consulting at Gleeds. "They could get an idea of how to plan space, even the view out of the chairman's window. And they can then use this model to serve their needs for years to come.

"We are now looking for enlightened clients who will see this as a benefit," says Robinson. "It's a mindset change more than a technological one. Change management can sometimes be a painful process, but this is a powerful approach and can save 10s of percents."