Coming soon in 3D

Coming soon in 3D

Architects and engineers are spoilt for choice when it comes to choosing a 3D CAD modelling package. Several drafting packages are available, each offering much the same thing, and there are a multitude of engineer-specific packages for modelling conditions, including airflow, acoustics and temperature. But contractors have been virtually forgotten in the expansion of 3D computing.

Designers are increasingly adopting 3D tools as they enable the creation of a virtual building which is instantly understandable. Contractors can benefit from this, too – a 3D model can be used to detect clashes between components before work begins and can also be used to precisely work out how to sequence the construction process.

Tools exist to do this but tend to rely on existing 3D models supplied by designers. This is fine if such a model exists but many architects still work in 2D despite the readily availability of 3D modelling tools. Design software specialist Graphisoft, which produces the 3D architects design tool ArchiCAD, has spotted a gap in the market and come up with a 3D modelling tool called Virtual Construction, aimed specifically at contractors.

What is unusual is that a single, integrated package will enable contractors to construct a 3D model and use it for tasks including estimating, sequencing and clash detection. It is set to be launched in the UK this month. “Our goal is to take two to three per cent out of the total project cost,” says Graphisoft chief executive officer Dominic Gallello.

The model has a “constructor” and an “estimator” component. The first stage is to use the constructor part to create a 3D model. This is a potentially massive task but Jim Bedrick, the director of systems integration for Californian contractor Webcor, says it is worth it – they are trialling the tool on five pilot projects, including the Renzo Piano-designed California Academy of Sciences.

“We would normally have to do a quantity takeoff from a 2D drawing,” he explains. “That’s a huge effort, creating the 3D model replaces that as you have created all the quantities which enables estimators to focus on real added value, and the model can be used for other purposes, too. It doesn’t take much longer to do than the traditional take-off and it’s certainly more reliable.”

The Estimator part of the tool enables contractors to create estimates based on their specific processes and how long these take. Bedrick says estimates are more reliable as there is less chance of missing something, and it is easier to identify changes when submitting revised estimates. It’s also much quicker.

“Once we have built the model it cuts the time to produce an estimate to one tenth of what it normally takes,” he says. “This means we can do more interim estimates.”

Once we have built the model it cuts the time to produce an estimate to one tenth of what it normally takes

David Strong, BRE

He says this means architect and contractor can work more closely together on designs. The architect can get instant feedback on how much building elements will cost and tailor the design to suit the budget as they go along rather than designing the whole building, finding out it’s too expensive and then having to fudge the finished design.

Construction sequencing is also made easier with Virtual Construction, according to Bedrick. “With Gantt charts you can see the time needed for task but not the spatial relationships. For example, you could have two gangs working on the project but the Gantt charts won’t show they’re working in the same place.”

He also quotes an example where two tower cranes were being used on a project. “We realised if we altered the schedule a little bit we could release one tower crane two to three months early,” he says.

“That represents quite a lot of money.” The software can also be used for clash detection, and the schedule can be linked to the estimator to discover what the costs are at any particular point in the project.

The big question with any new software is, will companies be able to overcome internal resistance to change? Bedrick acknowledges this is a potential problem but says this hasn’t been a problem at Webcor. “With both the estimating and sequencing tools we have had people with decades of experience and they say they have been waiting for a tool like this all their professional lives.”

Mervyn Richards, an IT consultant who was behind the single model environment at Heathrow’s Terminal 5, thinks Virtual Construction is a good tool. “It works and is the sort of thing we need,” he says.

At T5 the information in the 3D models created by the design team has then been used for construction, and ultimately will be used for operation and maintenance. This is the Holy Grail of 3D modelling, as only one model is needed from cradle to grave. “The problem with Virtual Construction is someone has to build the model, which is an additional cost,” he adds.

But the success of single model environments is dependent upon designers, contractors and facilities management teams all sticking to a strict set of procedures to ensure all the information is consistent. The great virtue of Virtual Construction is that it is self-contained and is ideal for contractors who want to use 3D modelling to improve efficiency but are not able or ready to go down the full single model route. Right now, that is most of them.