Digital Twin of Banteay Chhmar and Insights on Cultural Heritage Preservation and Transmission

Sokrithy Im, Director of the Department of Research, Training, and Communication at Cambodia’s APSARA National Authority.

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The ancient complex of Banteay Chhmar is one of our region’s most magnificent yet vulnerable cultural treasures. Our ongoing collaborative initiative, led by the APSARA National Authority of Cambodia under the Ministry of Culture and Fine Arts, focuses on building a living “Digital Twin”—a comprehensive spatial asset designed not just for documentation, but as a dynamic engine for active site preservation, collaborative scientific research, and global cultural transmission.

To understand the urgency of this mission, we must look at the current geopolitical and heritage landscape. The Royal Government of Cambodia is actively preparing a UNESCO World Heritage nomination for Banteay Chhmar. A successful nomination demands two critical things: first, demonstrating the site’s unique architectural and historical value distinct from Angkor; and second, establishing state-of-the-art site preservation frameworks. To answer this call, in March 2025, we forged an international, interdisciplinary collaboration uniting the heritage expertise of the Ministry of Culture and Fine Arts with the technological capabilities of the University of Tsukuba, the University of Tokyo, and Japan’s AIST. Funded by JSPS KAKENHI, our collaborative team launched an intensive campaign to construct a dynamic, highly accurate Digital Twin of the complex.

Banteay Chhmar is a masterpiece of the late 12th to early 13th centuries, built during the reign of King Jayavarman VII. It stands as the fourth largest temple complex of the Angkorian era, enveloping a massive eight square kilometers. Architecturally, it is uniquely significant: alongside the Bayon, it is the only other complex to display those iconic, enigmatic monumental face towers and vast interior perimeter bas-relief walls. However, its geographic reality presents severe challenges. Located deep in the northwest, 110 kilometers away from Angkor and a mere 19 kilometers from the border with Thailand, its remote nature has isolated it. It has historically been one of our least documented structures, and much of its expansive masonry is currently in a profoundly fragile, collapsed state of disrepair, highly vulnerable to structural degradation.

To map an environment that is simultaneously vast and actively collapsing, standard surveying is entirely inadequate. Our team designed a multi-modal “Scan-Process-Upload” pipeline that masterfully balances rapid field acquisition with millimeter accuracy. We deployed four specialized sensors: First, handheld SLAM LiDAR allowed us to cut through dense jungle foliage and rapidly traverse treacherous, collapsed stone piles, capturing over 4.6 billion points in five days. Second, static Terrestrial Laser Scanning was used at fixed stations to freeze highly unstable walls in digital space with extreme precision. Third, we executed extensive aerial and ground photogrammetry—nearly 10,000 images—to wrap our structural models in flawless, high-resolution stone textures. Finally, we utilized Matterport Pro3 technology to rapidly generate real-time spatial scans optimized for web applications.

Data is only useful if it can be accessed and utilized. Traditionally, massive 3D models end up locked away in hard drives or restricted by commercial platforms that compress data or limit file capacities. To solve this, our project integrates these massive datasets—individual files ranging up to 10 gigabytes—into a centralized 3D Database, or 3DDB. Co-developed with Japan’s AIST and powered by the Cesium geospatial engine, this platform enables anyone to stream full-scale, uncompressed point clouds directly inside a standard web browser. Because every single data point is embedded with true GNSS and global EPSG coordinate codes, researchers worldwide can measure distances, analyze angles, and cross-reference geographic locations in real-world space without needing specialized local software.

The Digital Twin serves as a practical, everyday tool for site management across three key areas. First, in Preservation, it gives us structural risk mapping. By comparing scans over time, we can detect stone shifting or wall deformations down to the millimeter before a catastrophic collapse occurs. Second, in Reconstruction, our engineers can design custom emergency shoring and scaffolding perfectly tailored to the irregular shapes of warped walls. Furthermore, it allows for “virtual anastylosis”—our teams can experiment with matching and reassembling fallen stones safely in a digital environment before moving a single heavy block in reality. Third, for Site Operations, it allows us to track invasive vegetation growth patterns and plan visitor wooden walkways that guarantee tourist safety, control crowd flow, and protect vulnerable soil profiles.

As we look to the future, our mission branches into two pathways of transmission. For academia, the Digital Twin provides an immutable spatial anchor where global researchers can pin their papers and field insights directly onto the corresponding stones. For the general public, it opens up immersive, virtual educational tours, allowing people worldwide to experience Banteay Chhmar and see digital reconstructions of its original state. Looking ahead into our upcoming developmental phases, we are integrating AI workflows for automated feature extraction from our point clouds, expanding our boundaries into comprehensive GIS frameworks, and completing scans of the outlying satellite temples.

The Dunhuang Academy has set the absolute global gold standard for digital heritage transformation. By building and deploying shared, open platforms like the 3DDB across the China-ASEAN corridor, we can form a resilient alliance. Together, we can ensure that our shared, vulnerable cultural treasures are eternally preserved in bits, accurately managed through data, and meaningfully transmitted to all of humanity.

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