PortalCam Recreates Sacred Heart Cathedral of Lourdes with SLAM+3DGS Technology for High-Precision Digital Preservation

When the vibrant stained glass of a century-old religious building meets cutting-edge 3D technology, the preservation and transmission of cultural heritage take on a whole new possibility. Tianbaonet’s PortalCam 3D space camera, with its groundbreaking SLAM+3DGS fusion technology, was first applied to the digital archiving project of the Sacred Heart Cathedral of Lourdes in Shamian, Guangzhou. This allows the historic building to achieve "immortality" in the digital world and sets a new technological benchmark for the protection of religious cultural heritage.

The Sacred Heart Cathedral of Lourdes is located in the Shamian Island architectural complex in Liwan District, Guangzhou. Built in the 16th year of the Guangxu era (1890), it was reopened in November 2010 after renovation, and now has a history of over 130 years. Its architectural details carry rich historical information: Gothic-style facades, pointed arch doors, spire windows, colorful stained-glass windows, and the Lourdes Virgin statue in the back courtyard, which together form a unique cultural symbol. However, traditional heritage preservation methods face three major challenges:

• High Physical Restoration Costs: The 2010 renovation project cost over 7 million RMB, covering eight major tasks, including the restoration of the Virgin Mountain and electrical system upgrades.

• Limited Monitoring Tools: Manual inspections can’t capture real-time changes in the structure of the building.

• Limited Outreach for Cultural Transmission: Visitors can only experience the architectural beauty through on-site visits, limiting the scope of cultural dissemination.

PortalCam combines SLAM and 3DGS technologies, collecting laser and visual data simultaneously to generate 3D models that are both structurally accurate and photorealistic. Equipped with a high-speed laser scanning module of 856,000 points per second and four fisheye + front-facing camera matrices, it can achieve 360° full-angle coverage, finely capturing details like the vaulted ceilings and stained-glass windows.

The operator walks around the church holding PortalCam. Using SLAM technology, real-time positioning and mapping are carried out while simultaneously capturing:

• Building Facade: Geometric features of the pointed arch doors, spire windows, and small corner towers.

• Interior Space: Ribbed decorations, pointed arch ceilings, and the light and shadow effects of stained-glass windows.

• Core Landscape: The spatial relationship between Virgin Mountain and the Lourdes Virgin statue.

• Surrounding Environment: The layout of the priest dormitory and workers’ living area.

The collected data is processed through the LCC Studio software, automatically completing three optimizations:

• Detail Enhancement: Gaussian pruning and merging for small structures like earthen textures and stained-glass mosaics.

• Structural Correction: Using laser data to correct modeling errors caused by tree obstructions.

• Model Lightweighting: Compatible with multiple platforms, such as web browsers and VR headsets, ensuring high fidelity, measurability, and cross-scene usability.

The generated 3D model supports multi-terminal roaming interaction. Users can freely switch perspectives and explore every corner of the cathedral across various devices. It also offers a measurement feature for precise dimension data, providing a scientific basis for future repairs and protection. The model can be directly imported into mainstream platforms like UE and Blender for secondary editing, easily enabling virtual exhibitions, digital studies, and other diverse applications.

As a leading provider of 3D visualization product solutions in China, Tianbaonet has been deeply involved in the spatial digitalization field for over 20 years. The successful implementation of the Sacred Heart Cathedral project not only demonstrates the adaptability of PortalCam in the digitalization of religious architecture but also highlights Tianbaonet’s leading advantages in technological transformation and scene applications. In the future, we will continue to iterate product technologies to provide "low-cost, high-efficiency, and high-precision" digital solutions for more religious buildings and historical relics, ensuring that cultural heritage is preserved and passed down in the digital age.