Towards the Semantic-aware 3D Digitisation of Architectural Heritage: The "Notre-Dame de Paris" Digital Twin Project

The introduction of digital technologies into the practices of documentation, analysis and dissemination of cultural heritage is today an important issue not only in the sphere of computer science, but also in the humanities and social sciences as well as in conservation sciences. New scientific challenges are today at the crossroads of a few trends that shape the contemporary landscape of digital humanities: the democratisation of 3D digitisation means, the emergence of new approaches for the massive cross-analysis of digitised content, the on-going harmonisation of heritage information systems through the formalisation of multidisciplinary knowledge. Whilst recent advances in digital technologies have made it possible to introduce new tools that are making documentation practices evolve within the cultural heritage community, the management of multi-dimensional and multi-format data introduces new challenges, in particular the development of relevant analysis and interpretation methods, the sharing and correlation of heterogeneous data among several actors and contexts, and the centralised archiving of documentation results for long-term preservation purposes. The restoration of Notre-Dame de Paris is today an unprecedented opportunity to gather and analyse the many analytical and documentary resources produced by a large number of scientists and heritage professionals from different backgrounds on the same building. In collaboration with the other working groups of the french CNRS (National Centre for Scientific Research) / MC (Ministry of Culture) task force on the restoration of the cathedral (stone, stained glass, wood, metals, structure, acoustics, heritage emotions, etc.), the "digital data" WG focuses on the introduction of an innovative digital ecosystem - a 'Notre-Dame de Paris' digital twin - to bring together, analyse and correlate the multiple levels of reading that converge towards the production of new knowledge on the cathedral, its transformations over time, its materials, the alterations produced by the fire, as well as towards the restoration project. By combining recent advances in 3D digitisation, knowledge engineering, computer vision and shape analysis, our approach will take into account two complementary aspects. On the one hand, the description of the different steps taken by scientists to move from the observation of raw data to their interpretation in relation to other contextual data from the analysis of typical operating chains. On the other hand, the analysis of the spatial, temporal and semantic overlap of regions of "multidisciplinary interest" based on the correlation of annotations, vocabulary terms, qualitative attributes and morphological features.