FORWARD THINKING

The idea of the building information model (BIM) was first advanced in the mid-1990s, as part of the Egan report on remaking the construction industry. The idea was that designs for disparate elements could be brought together in one place, and information for all phases and aspects of a project fused, allowing better coordination of designs, better construction planning and detection of errors and conflicts.

But a decade on, the industry is still only beginning implementation. "To tell the truth we are just scratching the surface," says Laing O’Rourke design IT manager Sam Collard, which is gradually rolling out BIM on major projects. Other major contractors, including Skanska and Bovis LendLease, have similar roll-out programmes, as do the big multi-disciplinary consultants, but much of the industry still works with traditional CAD tools and, even where they do not, the design deliverables are traditional drawings taken from the 3D model of a building.

Collard sees a gradual evolution of design and construction models in three phases. First is the use of 3D models by the structural engineer into which information from services, M&E and H&V subcontractors, can be added. Drawings in 2D from traditional CAD can be merged into that model. Second is the full 3D model, which is becoming more common as designers become versed in 3D design and acquire software to do it. The third phase – not yet reached – is the intelligent 3D model that has components that "know" what they are, where they fit and how they affect other elements. This comes about with an object orientated model providing a digital representation of the building.

For Bovis LendLease CAD systems manager Daryn Fitz this last definition is key. "Many people think the BIM is a 3D visual model you can fly through," he says, "but that is not so. It is the digital interconnection that matters, which may not even appear as a visual representation at all." Fitz believes AutoDesks’s Revit is one of the few software tools around that give this capacity.

Problems with take-up are not simply due to lack of available software, but are also contractual and economic. A large part of the industry still works in 2D, and is not motivated to change. Architects and structural designers do not see what’s in it for them, and are paid a fee to do a job and produce a certain output, usually in the form of drawings. Who, for example, is going to produce the software for building components that fully specify them as objects with intelligence?

There has long been a hope that electronic catalogues would become available from manufacturers, with parametric software definitions of products that could then be slotted into models. "People already have libraries they have built up for conventional working," says Collard. "That is a problem, as they don’t want to waste past work."

BIM benefits accrue mainly to the contractor, as modelling a project allows the contractor to spot potentially costly problems on site and to improve scheduling and avert safety problems. "It can save a lot of cost and grief on site, but designers will not thank you for raising problems with designs and finding errors, particularly as it could stray into litigation territory," says Fitz.

Collard bemoans the fact that the burden is on contractors, and believes designers should be producing clash detected and checked drawings. Despite these difficulties, things are moving forwards. Laing O’Rourke has been learning major lessons about BIM since using it on major projects since 2004. Younger engineers, brought up on computer games, take to the technology more quickly, says Collard, and are happy to do setting out from models. He thinks substantial steps towards BIM will happen in the next 18 months, and that "full BIM" might be achievable in the next five years or so.

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