The Sumerian city of Uruk was one of the largest metropolises in the world around 5,500 years ago; its ruins are now a UNESCO World Heritage Site. In order to preserve it and research it better, archaeologists have now created the first digital twin of Uruk. Unlike a mere 3D model, the Uruk VR also makes it possible to include and display real-time data in the digital model. This can help, among other things, to plan future excavations.
One of humanity’s earliest advanced civilizations emerged in Mesopotamia, the Sumerian Empire. One of the centers of the Sumerian Empire was the city of Uruk. More than 50,000 people lived in this metropolis on the banks of the Euphrates as early as 3500 BC. In addition to residential buildings, workshops and palaces, it also included several large temples. “The archaeological remains of Uruk today cover an area of more than five square kilometers and contain the material evidence of one of the first cities in the world,” explains Max Haibt from the German Archaeological Institute.
Digital twin: More than just a 3D model
This makes it all the more important to preserve these unique relics, which are now part of the UNESCO World Heritage, as intact as possible and to research them in a non-destructive manner. To make this possible and at the same time monitor the condition of the ruins, Haibt and his team have created a digital twin of Uruk for the first time. “Such a digital twin differs from a purely geometric digital model because, in addition to the 3D model, it also includes real-time data from sensors,” explains Haibt. This VR version of Uruk enables virtual, high-resolution exploration and exploration of the ruins of Uruk and their surroundings and also facilitates the planning of excavations and sampling.
But for Uruk’s digital twin, the team had to overcome some technical challenges. In order to map the ruin field with high resolution and georeference, Haidt’s archaeologists used a remote-controlled long-range drone that has a range of more than 100 kilometers and can carry a kilogram of payload. For six days she flew over Uruk in a narrow search grid and created around 32,000 aerial photos of Uruk and the surrounding area. Each shot was precisely geotagged and assembled into a single georeferenced model using 3D photogrammetry software. This 3D model was based on 9.3 billion mesh polygons and 1,024 texture layers.
Only possible thanks to gaming technology
The problem, however: “Even advanced graphics software like Blender or 3DsMax can typically load and render a maximum of 15 million polygons,” explains Haibt. For static 3D models, this could be avoided by rendering in sections, but the digital twin must be rendered in real time. The team found the solution in state-of-the-art gaming technology. The Nanite technology integrated into a gaming engine makes it possible to combine the polygons into virtual clusters for rendering and thereby stream and visualize the extensive data set in real time.
The result is a virtual image showing the ruins of Uruk and its surroundings over an area of 40 square kilometers and at 8k resolution. “The spatial resolution of the first prototype is still below the target at 27 centimeters and a texture resolution of around three centimeters. Nevertheless, the quality is already sufficiently high to use the model as a general context for the integration of further spatial data,” says Haibt. The virtual flight over Uruk makes visible for the first time what and where was excavated, examined and uncovered in a century of archaeological research in the Mesopotamian city.
The archaeologists see their model as a first step towards an even higher resolution VR twin of Uruk, supplemented by further data. The digital twin can already be used by researchers to plan and evaluate their projects. There will also be “guided tours” in summer 2024. Uruk-VR will then also be publicly accessible for independent exploration.
Source: German Archaeological Institute; Specialist article: International Journal of Digital Earth, doi: 10.1080/17538947.2024.2324964