New Dimensions in Modelling

31 July 2006 (Last Updated July 31st, 2006 18:30)

Chris Mugan reports how 3D modelling is increasingly being used to ensure coordinated planning and information sharing.

New Dimensions in Modelling

Long a pipedream of IT-conscious architects, 3D modelling has finally come of age. In recent months, we have seen a much more wide-ranging use of the programs that allow designers to create 3D building plans.

This goes beyond simply visualising a project. Instead, architectural firms are using it to facilitate more efficient forms of collaboration. Designers and engineers can work on their own parts of a model, adding to it and sharing information with others.

This is useful for complex schemes, such as HOK's £700m Bart's Hospital in London, the largest health-related redevelopment under the UK Government's Private Finance Initiative, with floor space of two-and-a-half million square feet.

Designers have drawn up a 3D model using the established Architectural Desktop (ADT) system. When architects change one parameter, the software applies it to all relevant areas. This really speeds up the design process, says CAD manager Miles Walker.

"It means you can be more flexible," he explains. "One block is a multi-storey building, but to change the height of a level by 300mm is quite easy. Once you have the dimensions of the rooms, ADT generates ceiling slabs for all of them, and there are
6,000 of them in Bart's."

COORDINATED PLANNING

On the Bart's project HOK shares its 3D models with structural engineers Skanska Technology and Yolles. Working to a scale of 1:100 means there is not enough detail to plan the deployment of hospital equipment, but designers can still create a
structural model. "We can use this to drive the construction and end up with coordinated documents for our clients," adds Walker.

Now the firm is migrating its users from ADT to AutoDesk's Revit Building, a more intuitive product, thinks Walker: "ADT works well, but Revit is easier to pick up. I wanted to make sure designers used it first, rather than CAD technicians, and they've
been pretty receptive. The transition is more painful if you have a grounding in AutoCAD, though it's better if you have that foundation."

NEW PLANS FOR TERMINAL 5

Coordination is also important in the design of Heathrow Airport's Terminal 5. Planner and design manager Arup is working with a range of partners that include Richard Rogers Partnership and HOK.

The technical complexity of a project featuring a
control tower and transport links led to the client, BAA, and its contractors creating a single CAD system in which to create, store and share data. This is known as the Single Model Environment (SME).

Designers create 3D graphics in ADT that are divided into easily identifiable layers covering areas such as ductwork and flooring, so that each discipline retains ownership of its information while accessing that of others. The SME converts these
files into another format using NavisWorks, which allows clash detection software to detect any anomalies between parts of the model.

"It is not just the largest firms that are investing in 3D."

One activity that requires special attention is site logistics, especially in the interchange plaza, where teams for the multi-storey car park, main building and rail station work in close proximity. Here, Arup has used 3D models to facilitate what it
calls 4D construction planning, where time is added as a fourth dimension to programmes with CAD data.

Visual communication of the construction sequence can enable early and ongoing coordination. 4D planning means contractors can compare phasing options and report progress more easily. On the Terminal 5 project, the detailed plan indicated that six
months of efficiencies could be gained against the initial master programme, as well as highlighting clashes that could have cost £2.5m in delays.

THE MODEL SCHOOL

It is not just the largest firms that are investing in 3D. The medium-sized Bristol-based practice Stride Treglown used Revit for the design of the £25m Richard Lander School in Truro, Cornwall. Stride Treglown associate Stewart McDowall
believes the software is now more accessible to medium-sized firms, especially those looking to use parametric modelling to create a complete model of a building and pull out plans and elevations.

With 3D modelling, McDowall could quickly see how new ideas would affect the overall design: "Using Revit we could try out different ideas and immediately see how they affected the building's dimensions."

"The software makes it easy to adjust and
experiment with a design, as its parametric technology automatically updates all the associated data – there's no need to make calculations or manual adjustments. We could keep track of the changing floor space as the design progressed, and thus
retain control."

McDowall found he could respond more quickly to design changes. His firm had to adjust wall thicknesses when new acoustic regulations came into force, and the school's IT requirements changed as the project progressed. Originally, only 10% of
classrooms had interactive whiteboards, but now all of them are to be equipped in the same way. As a result, the network hub room has grown from 10m² to 70m² and the amount of cabling and cable ducts required has grown accordingly.

Once again, Revit ensured changes could be made quickly and were automatically co-coordinated throughout the model. There was also the challenge of designing a high-profile building. The school for 1,350 11–16 year olds shares its website with a
public library and other community buildings, and so public consultations and discussions with teachers were an integral part of the design process.

"With this technology, when architects change one parameter, the software applies it to all relevant areas."

MAKING IT REAL FOR THE CLIENTS

Stride Treglown had to show staff what their rooms would look like, something laypeople would not necessarily understand from examining plans.

"3D modelling made the process a lot easier," says McDowell, "We could have shown teachers where their blackboards were with pen and paper, but that would have taken ages and there are 400 rooms. With parametric modelling we could just pull out 2D plans from the model."

The software has also been used to export schedules for doors and other fittings. "For such a large building this is quite a task," explains McDowall. "Also, £1.5m worth of furniture has been commissioned and we have been able to send the
designers exact dimensions to ensure a perfect fit."

These cases show that business information modelling is more than just a gimmick. When introduced with care it brings quantifiable efficiencies in terms of cost and time. Ultimately, though, the point of 3D modelling is more control for everyone, from architects, engineers and builders to, ultimately, the clients themselves.