Heritage-BIM model to future proof an Opera House

Author:Hazlinda Mohd Nuron

The Saigon Opera House, one of Ho Chi Minh City’s most elegant and historical cultural assets, has a new digital identity to manage, preserve and protect this iconic building.

Built in 1898 by architect Eugene Ferret, and modelled on the Petit Palais in Paris, the much-loved municipal performing arts venue is also a heritage tourist attraction. The building was identified as being at risk because of its location in the heart of South Vietnam’s busy city.

Work carried out on the Metro beneath the theatre might further degrade the historic structure. Accurate digital condition surveys were needed to help the authorities successfully manage future renovations or even a complete reconstruction.

大火几乎摧毁了巴黎的巴黎圣母院大教堂的消息给了该项目的额外动力。

越南Portcoast顾问公司的总主任Pham Anh Tuan先生负责这项工作，组建了一个30人的调查和工程团队来解决该工作。

With vast previous experience of Leica Geosystems products, Mr Tuan chose a fleet of Leica Geosystems’ total stations, GNSS and 3D laser scanners, together with the latest integrated software, to deliver the project’s ambitious goals.

A three-phased approach

工作的第一阶段是构建基本遗产bim模型。由于原始的设计文档和结构图随着时间的流逝而丢失，因此需要两个来自不同来源的数据集。

The raw spatial data of the existing structures was collected using geodetic equipment, cameras, UAV and 3D laser scanners, while the technical, historical information was sourced from national archives and research centres.

The second phase involved the modelling and processing of point cloud data to construct a 3D digital representation of the current status of the theatre. Additional information on colours, materials, patterns, as well as details of origin, history and cultural significance were integrated to create a complete BIM model.

The third and final phase utilised the BIM model to create a precise 3D visualisation, which could be shared with stakeholders, usingLeica TruViewand JetStream Viewer.

Mr. Tuan said, “The digitalised deliverables could only be achieved with cutting edge equipment and software. Using the resulting BIM model we created a precise reality capture visualisation using VR (Virtual Reality), AR, (Augmented Reality), and MR (Mixed Reality) techniques, ultimately sharing this with stakeholders and the public through an impressiveinteractive virtual tour,featuring an accurate 3D model of the Saigon Opera House.”

The extensive Leica Geosystems software portfolio was used in all phases of the project:Leica Infinityfor georeferencing the point cloud data, Leica旋风3dr创建雕像和浮雕的数字模型和莉卡CloudWorxplug-in for Revit to add the top roof frame truss system to the BIM model.

Capturing reality inside and out

Using aLeica Nova TS60,twoGNSS GS18 T, oneiCON iCR80和两个iCON gps70,调查团队设置了350多个地理参与扫描站，以准确捕获从舞台和礼堂到屋顶圆顶，地下室和外墙的点云数据。

As it was not possible to physically climb onto the roof, a crane was used to lift aLeica ScanStation P50三维激光扫描仪position to capture up to 1km of the area around the opera house in High-Dynamic Range (HDR) imagery and survey-grade quality.

For the complex interior geometry, particularly in the narrow attic and basement spaces, where fast scanning time, accuracy, stability and manoeuvrability were essential, theLeica RTC360and theLeica BLK360were ideal.

FourLeica RTC3603D laser scanners were used for the columns, statues, reliefs, patterns, chandeliers and exterior details. The light and compact design of the BLK360 overcame the challenge of scanning the air-conditioning system located in the confined attic space.

“The accuracy of measurement and the density of the measured points was a key factor in our choice of hardware. High efficiency, flexibility and reliability of this equipment saved us time and manpower in every aspect of the project from initial control and georeferencing to the laser scanning and registration process,”said Mr. Tuan.

A priceless return on investment

Confidence in Leica Geosystem’s digital technology amongst Portcoast’s young engineering team has engendered a renewed sense of pride in the history and cultural values the building represents.

Mr. Tuan explains,“In the event of a catastrophe, the entire structure could be rebuilt from the digital record. When necessary in the months and years to come, the digitalised data can also be used to print 3D models needed for high accuracy casting to replicate the original decorative features. Digitalisation has ensured the beauty and majesty of the Saigon Opera House will continue to inspire future generations of residents and visitors to the city.”

Following the success of this heritage project, the municipal authorities now have scope to consider applying digital documentation methods to some 150 buildings of historical, cultural and artistic significance in Ho Chi Minh City.