Innovative Digital Environments for Knowledge, Diagnosis, and Management of Low-Accessible Architectural Heritage.

Low-accessible Cultural Heritage, such as hypogeal structures, sites at risk, or fragile architectural systems, poses a considerable challenge to conservation practices, especially in terms of physical documentation, condition monitoring, and stakeholder engagement. These sites often suffer from limited accessibility due to morphological complexity, safety concerns, or conservation regulations. Despite the growing adoption of digital tools for Cultural Heritage management, there is still a lack of integrated and scalable procedures capable of addressing the specific issues related to inaccessible environments. The present research, developed within the framework of the national project DIGIT-ACCESS – Digital Gateway for Low Accessible Heritage Architectures (PRIN PNRR 2022), aims to define a flexible, multi-scale, and interoperable methodological workflow. It has been elaborated to support the knowledge, diagnosis, and conservation planning of hypogeal heritage in low-accessibility conditions. Key objectives include the development of toolkits for remote analysis, the formalization of informative flows between disciplines, and the enhancement of stakeholder awareness through virtual environments. To address these goals, a systematic literature review was conducted, supplemented by a bibliometric analysis using VOSviewer, to identify existing gaps and outline the state-of-the-art in the field. The outcome was the creation of a structured knowledge base collecting international case studies, digital platforms, and diagnostic techniques. In this scenario, the methodological workflow integrates: i) advanced surveying techniques (UAV photogrammetry, terrestrial laser scanning, mobile mapping systems); ii) digital models (image/range-based models); iii) spatial analysis (GIS-based systems); iv) automated interpretation tools (Machine Learning, Reverse Engineering); v) immersive technologies (VR/AR), and vi) collaborative platforms for knowledge sharing (web-based systems). The defined methodology is applied and validated on a representative hypogeal site in the rock-cut architecture of the Unesco site of Matera (Italy). The case study demonstrates the potential of digital tools for managing inaccessible assets, supporting remote collaboration between experts and institutions. Expected outcomes of the general research project include the creation of a digital toolkit for scalable and replicable applications on similar sites, an integrated information system for managing multiscale and multidisciplinary data, and the definition of innovative workflows for preventive conservation. The research work also promotes sustainable and inclusive strategies for heritage management, enabling digital access and participation, and contributing to the development of resilience policies and digital heritage infrastructures.