A tripod-mounted rotating scanner is silently examining the external sandstone walls. In its sights are the graceful arched entry doors welcoming people to Government House.

This is all part of the work of maintaining the historic and state and nationally significant site of Government House and preserving its history for future generations.

3D Spatial Surveying is the latest technology used by architects, structural engineers and conservationists and, now, being employed at Government House.

A historic site the size, scale and featuring the intricate Gothic Revival architectural detail of Government House benefits from 3D scanning as it captures far more accurate profiles and dimensions of each nook and cranny than can be achieved through physical measurement. It is an important way of identifying areas for maintenance, informing decisions on everything from repair work to lighting requirements. 

While the state-of-the-art scanner is doing its work, 3D Spatial Engineer, Thomas, from contracted firm Veris, explains the process.

The 3D laser scanner, a Leica P40 Scanstation, will capture over a billion points and 19000 images in the next two to three days in a 360-degree high resolution survey of the external walls, surfaces and features of Government House. The Leica measures a scanned object by emitting laser pulses and recording the subsequent intensity of their return when reflected off it. Scanning can be performed with millimetre precision and is commonly used for heritage documentation.

The Leica Scanstation delivers highest quality 3D data and HDR imaging at an extremely fast scan rate of up to 1 million points per second at ranges up to 270 metres.

This data will then be processed at the Veris studio, where a 3D computer model, known as a REVIT model, will be created from the captured points and imagery. 

There are more than a few hidden stories to these sandstone walls … Estate Manager Dayn comments: ‘To truly know a building as old and significant as this one, dating from 1845, we need to identify areas for required restoration that may not be visible to the naked eye. The 3D model will enable me to prioritise work required on the House and accurately identify the type and scale of restoration needed.’