In recent years, advanced digital technologies have driven an outstanding paradigm shift in the field of architectural heritage, particularly for building modelling, historical documentation and touristic promotion. Nonetheless, they show great potentialities in the field of assessment and control of the state of conservation of heritage buildings. In particular, close-range and aerial photogrammetry have increasingly relied on low-cost and user-friendly tools and procedures, with a high degree of automation that makes them accessible to specialists who are foremost involved in architectural diagnosis and conservation, rather than in remote sensing sciences. In this framework, this paper provides a scoping review of 117 publications, based on the PRISMA protocol, from Scopus and Web of Science databases, related to the employment of photogrammetric models and methods, with specific focus on the targets and purposes of the diagnostic process, including decay mapping, structural monitoring and modelling, non-destructive investigation and multi-source documentation. In detail, the results point out that current studies mainly support robust processing of large amounts of information from direct observation of surface alterations, systematic correlation between materials, construction characteristics, visible anomalies and experimental measurements, as well as multi-disciplinary collaborative workflows through remote inspection and harmonized data management. Further improvements were identified, including standardization of acquisition procedures, automatization of elaboration pipelines, integration of real-time data, validation of diagnosis decision-making support tools and scalability to networks of assets.

The digitalization of the historical-architectural heritage for virtual reality (VR) applications is crucial within the contemporary scientific and technical debate for several aspects. In fact, beyond the exploration for education and entertainment purposes, the employment of three-dimensional (3D) reality-based and computer-based models and environments seems to be very promising for performance assessment and risk management as well. Particularly, in order to develop and validate smart, low-cost and user-friendly tools, which might apply even in cases of limited time and budget, the present paper is going to propose a methodological workflow based on thematic virtual tours of 360° scenes, which integrate a variety of informative contents and digital products as external hotspots/switches. The VR tours, where 3D models might play a key role for an accurate representation of relevant parts and/or analytical elaboration of further data, are conceived as flexible and scalable solutions, supporting users, technicians and authorities through remote access, diagnosis of the state of conservation and communication of safety measures. The application of the proposed methods and techniques to a representative case study, the Norman-Swabian Castle of Gioia del Colle (Ba), South Italy, is presented in order to illustrate the achievable results and highlight the benefit of innovative “digital” solutions for data collection, storage and communication, compared to the traditional “analogical” practices. In detail, a Web-GIS platform, developed within a previous research project, is integrated with direct links to three thematic virtual tours that provide added contents for inclusive dissemination (timeline schemes, aerial views, 3D sculptural and architectural details), performance assessment (diagnostic reports, decay maps, 3D reconstructions of technical components) and risk management (exit signs, help instructions, warnings). Thus, the VR tours, while documenting realistically the state of the site, might act as host environments of digital products, at increasing complexity, all displayed according to an intuitive and accessible communication approach.Highlights:• Virtual tours of 360° scenes, linking thematic digital contents, are proposed as intuitive and versatile tools for smart documentation, conservation and protection of historical buildings.• The role of 3D reality-based and computer-based models is discussed toward their integration and correlation within thematic virtual tours of 360° scenes.• The potential of immersive environments for sharing knowledge about conservation issues and training users on safety measures in historic buildings is underlined.

The promotion and dissemination of architectural heritage for cultural enhancement and touristic enjoyment are increasingly focused on innovative ICTs, including 3D Geographic Information Systems, photorealistic models and scenes, and VR/AR immersive digital environments, which enable the interaction of visitors with a variety of informational contents, both educational and specialist. Within the above-mentioned framework, this paper will firstly outline the general objectives of the project “3D-IMP-ACT”, which has been funded under the international cooperation programme IPA CBC Interreg Italy-Albania-Montenegro. In this research, some ICT tools are tested and validated to create “virtual networks” of international ancient architectures and sites, based on the identification of “physical networks” of common historic, environmental and technical characteristics and infrastructural connections, in order to address coordinated strategies and transversal policies for development and management. Then, the paper will describe and discuss some results from the design and implementation of the project WebGIS system, which integrates virtual tours of 360° panoramas, 3D models from photomodelling of pictures taken by drones, multimedia contents, and 2D/3D historic evolution schemes within a single platform, where the users are supported in recognizing and exploring the tangible and intangible correspondences among the project pilot-cases. In conclusion, some remarks will be proposed on the potential benefits of the platform as an expert system which supports the technical assessment and control of architectural heritage toward maintenance, refurbishment and conservation.