Some of the biggest buildings of the new-look Christchurch are being put together virtual piece by virtual piece, thanks to remarkable 3D technology.
More than a decade after Building Information Modelling (BIM) made its debut in the construction industry, the concept has been pushed to the point where many of the centrepieces in the rebuilding of Christchurch are being assembled in detail on a computer well before workers set foot on the site.
It comes as the Government starts a BIM acceleration committee, as part of a productivity partnership with the goal of 20 per cent more efficiency in the construction industry by 2020.
BIM expert Jason Howden, who has worked on huge projects ranging from Royal Manchester Children's Hospital to a 1.5km terminal expansion at Jakarta Airport, has returned to his hometown to assist with Christchurch's $40 billion rebirth.
His team at architectural firm Warren and Mahoney is now using the technology to tackle several large-scale operations, including three buildings of 40,000sq m, covering a city block.
Because contractors, designers, architects and engineers all worked from a single three-dimensional design, all of the components of a building - from steel girders down to interior fittings - could be designed and positioned into the digital model in a single process.
Once the design was complete, builders on site could use a tablet computer to view the BIM plan as a digital overlay on top of what they were physically seeing.
"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 a render of the BIM, overlaid on a live picture feed so workers can see exactly what the project is supposed to look like and work precisely to plan."
Mr Howden said this approach allowed construction teams to spot hurdles, make work sites safer, slashed cost and potentially halved construction time.
While New Zealand had lagged behind in its take-up, BIM designing was expected to become more widespread here, and especially in Auckland, said John Walsh of the New Zealand Institute of Architects.
•The easiest way to grasp Building Information Modelling is to picture a set of gigantic virtual Lego pieces.
•A series of Lego blocks form the core of the design, while other blocks are brought in to make special sets, such as a hospital, airport, or prison.
•A prison set would focus on security and safety; a hospital set would be care-focused and designers would prioritise elements such as light.