Segmentation protocols in the digital twins of monumental heritage: a methodological development

The paper shows an advancement of the research that the authors have been carrying out in recent years in semantic structuring of digital architectural representations field, with a focus on the issue of uncertainty of annotations. The studies carried out in this regard have shown how the domain experts specialization determines a vision and interpretation of the same architectural object that we could define “categorized”. The interest was, then, in verifying which categories of experts have a greater degree of agreement in classifying and segmenting architectural elements, to highlight which specializations contribute the most in enriching the semantic reasoning about such forms. Aiming to broaden this reasoning, the research was deepened with annotation sessions concerning architecture examples that didn’t correspond to the classical orders rule but included wider fields of historical heritage (from sacred to fortified architecture). The aim is to verify whether the uncertainty of annotation is actually ascribable to a specific segment of the historical heritage, for example, the classical world, or whether the question is broader and as such in needs deeper thinking.

The Role of the Graphic Element in the Context of Playful Games for Cultural Heritage

This paper aims to investigate the conditioning that the use of playful games requires the role of graphic element for disseminating and promoting the Cultural Heritage. Within the CHROME project, which has, among the various objectives, the definition of an innovative strategy to promote the three Charterhouses of Campania, it comes up with the idea to plan a playful game placed in one of the three monasteries. Its purpose is to provide a first knowledge, both in relation to the spatiality of a Carthusian monastery and to the life of a monk of the Order, exploiting the playful dimension of the games. Since that the proposed location for the game is a monastic complex whose modeling is gained by range-based and image-based survey processes, the project shows the definition of a methodology to generate digital three-dimensional models, whose geometric genesis is at the same time both topologically coherent and enjoyable on the selected technology platform. Once obtained the scene in which the narration develops, it must qualify as a visual device able to activate the sensory involvement, the share and the exploration. For this reason, some expedients (illumination techniques, framing, distortions, sonorous scenes) have been studied to stimulate the player and to communicate cognitive messages related to the game space using the principle “show, don’t tell”.

Re-contextualizing the standing Sekhmet statues in the Temple of Ptah at Karnak through digital reconstruction and VR experience

Recent trends in the Digital Humanities – conceived as new modalities of collaborative, transdisciplinary and computational research and presentation – also strongly influence research approaches and presentation practices in museums. Indeed, ongoing projects in museums have considerably expanded digital access to data and information, documentation and visualization of ancient ruins and objects. In addition, 3D modelling and eXtended Reality opened up new avenues of interacting with a wider public through digital reconstructions that allow both objects and sites to be presented through visual narratives based on multidisciplinary scholarly research. The article illustrates the use of 3D digital reconstruction and virtual reality to re-contextualise standing statues of Sekhmet in the Temple of Ptah at Karnak, where they were found in 1818. Today, they are on display at Museo Egizio, Turin. The theoretical framework of the research and the operational workflow – based on the study of the available archaeological, textual, and pictorial data – is presented here.

Reconstructive 3D Modelling and Interactive Visualization for Accessibility of Piffetti’s Library in the Villa della Regina Museum (Turin)

This research is realised in the framework of a project recently funded as part of the PNRR (National Recovery and Resilience Plan) in the Accessibility sector. The working team has been established in the framework of the scientific agreement between the Museum of Villa della Regina in Turin, the Department of Architecture and Design at Politecnico di Torino, and the Department of History, Drawing and Restoration of Architecture at Sapienza Università di Roma, and includes knowledge from art history, digital surveying, 3D modelling, and digital solutions for cultural heritage. The research involves the reconstructive 3D modelling of Piffetti’s Library, once placed in the cabinet toward midnight and west inside the Villa della Regina and today in the Palazzo del Quirinale, and its interactive visualisation through augmented reality (AR) and virtual reality (VR) aimed at accessibility.

3D Heritage Data Fruition and Management. Point Cloud Processing for Thematic Interpretation

Technologies and digital tools such as laser scanning and photogrammetry are nowadays widely used in the field of architectural heritage survey, being able of producing 3D models characterized by high metric and morphological accuracy. These databases are becoming essential also for the development of more effective interventions on heritage buildings. Despite the advancement of increasingly automated analytical procedures, the management and analysis of point cloud models can still be quite time-consuming and complex, depending on specific assessments to be carried out. In the direction of optimizing these processing steps, several research is being carried out by applying Artificial Intelligence processes to make predictions based on sample data. The aim of the paper is to analyse point clouds processing focusing on geometric and radiometric features for diagnostic analysis. A specific focus aims at analysing possible in-depth uses of the intensity value as a benchmark for historical surfaces assessment, toward an optimized models’ interpretation and classification of the 3D data points, integrating data and information from different sensors. Point clouds under analysis have been carried out by different acquisition techniques; this provides an interesting opportunity to compare the results in terms of intensity value produced by different sensors. The paper will analyse the State of the Art, also illustrating a set of outcomes obtained by the authors, deepening two specific case studies, in order to outline not only the main background and shortcomings in managing complex database, but also possible innovations pointing out new research questions.

From semantic-aware digital models to Augmented Reality applications for Architectural Heritage conservation and restoration

The paper presents the integration of Augmented Reality and Mixed Reality tools for the built Heritage management and control, both remote and on-site, and real time interaction, starting from a preliminary set of experimentation carried out for knowledge and tourism purposes.
Within the framework of these experimentations, specific data inventories are related to the IFC model, and all these data are collected on a cloud-based platform, allowing the “dialogue” among platform and applications. Therefore, BIM integration is the first step of the procedure, considering a workflow where data capturing, digital documentation, and data modeling and aggregation are the entry level to manage applications able to give an added value in gaining the greatest technical benefit from digitization. Mapping the main features and the state of conservation is the second step, including geometric features, historical knowledge, documents and pictures related to materials, diagnostic analysis, etc.
Starting from AR applications developed on several case studies, including historical buildings, museums and a church, aimed at an immersive on-site navigation thanks to a set of additional information related to the digital model, experimentations oriented to technical uses are presented.
An extension of applications for the analysis and interpretation of architectural heritage and technical uses can be an effective support in restoration, conservation and maintenance of historic buildings, by enhancing the real world through virtual objects and creating a new mixed reality environment for technical users.

NEURAL RADIANCE FIELDS (NERF) FOR MULTI-SCALE 3D MODELING OF CULTURAL HERITAGE ARTIFACTS

This research aims to assess the adaptability of Neural Radiance Fields (NeRF) for the digital documentation of cultural heritage objects of varying size and complexity. We discuss the influence of object size, desired scale of representation, and level of detail on the choice to use NeRF for cultural heritage documentation, providing insights for practitioners in the field. Case studies range from historic pavements to architectural elements or buildings, representing diverse and multi-scale scenarios encountered in heritage documentation procedures. The findings suggest that NeRFs perform well in scenarios with homogeneous textures, variable lighting conditions, reflective surfaces, and fine details. However, they exhibit higher noise and lower texture quality compared to other consolidated image-based techniques as photogrammetry, especially in case of small-scale artifacts.

Visual Programming for a Machine Semi-Automatic Process of HBIM Models Geometric Evaluation

The topic of the relationship between digital restitutive model and measurement can find important development possibilities in machine procedures, in particular in the Historic Building Information Modeling (HBIM) field. In fact, BIM uses parameterized and pre-defined objects in special 3D libraries articulated according to the architectural components, not corresponding to ideal configurations. Moreover, BIM platforms are limited in modeling deformations, damages, and degradations. The paper investigates the advantages of using visual programming to increase the possibilities given by the BIM software, born for new buildings, by carrying out a semi-automatic assessment of the geometric reliability directly in the BIM environment. In particular, the algorithm compares model’s shapes with the cast of the artifact given by the point cloud, and declares it, by automatically filling a dedicated reliability parameter linked to the BIM model element.

A Proposal of Integration of Point Cloud Semantization and VPL for Architectural Heritage Parametric Modeling

Current architectural survey processes utilize point clouds generated by laser scanning and digital photogrammetry. Increasingly, these surveys produce 3D models, particularly parametric models, in what is known as the “scan to 3D model” or “scan to BIM” process. However, the phases of analysis and classification of architectural elements, segmentation and semantization of point clouds, and semi-automatic modeling remain complex and labor-intensive and require an active role commitment of the scholar or modeler. These steps are usually performed manually, resulting in high subjectivity and low reproducibility. This paper proposes a reproducible workflow that automatically segments point clouds, identifies geometric shapes by comparing them with a library of ideal geometries, and extracts necessary points for modeling through mathematical analysis. The extracted information is then processed using a visual programming algorithm, imported into the VPL environment, and used for automated modeling. Initial results from an ongoing experiment on the automated modeling of vaults using point clouds from surveys are presented.