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Structural health monitoring of Cultural Heritage (CH) is a key topic in research, as well as damage identification and failure assessment. Hence, it is mandatory to have a proper documentation as basis for further analysis.3D models from photogrammetric and laser scanning surveys usually provide 3D point clouds that can be converted in meshes. These models can be used for different purposes, from documentation to visualization to structural analysis. The point clouds usually contain noise data due to different causes: non-cooperative material or surfaces, bad lighting, complex geometry, and low accuracy of the instruments utilized. Noise not only deforms the unstructured geometry of the point clouds, but also adds useless information and reduces the geometric accuracy of the mesh model obtained and, consequently, the results of any analysis performed on it. Point cloud denoising has become one of the hot topics of 3D geometric data processing, removing these noise data to recover the ground-truth point cloud, adding smoothing to the ideal surface. These cleaned point clouds can be converted in mesh with different algorithms, some automatically processed by photogrammetric software and then turned into volumes, suitable for different uses, mainly for structural analysis.The paper wants to analyse the geometric accuracy of few automatic processes available into commercial and open-source software for the conversion of superficial 3D meshes into volumetric models that can be used for structural analyses through FEA process.DOI: https://doi.org/10.20365/disegnarecon.32.2024.15

Si presenta un aspetto dell’attività di ricerca condivisa con gli studenti che hanno approcciato il tema di studio Analisi Comparative e Ricostruzioni Certificate per una corretta archeologia sperimentale delle artiglierie romane. L’occasione è sembrata utile per riflettere sulla tangibilità dei modelli in cui disgregare, alla luce delle attuali tecnologie, i confini tra valori materiali e immateriali. Allo scopo si presentano rilievi di prototipi fisici di catapulte di epoca repubblicana imperiale, ricostruite sulla base di tre tipologie di fonti e testate nel funzionamento. Passando dall’interpretazione delle acquisizioni fotogrammetriche al controllo numerico dei modelli “basati sulla realtà”, si guarda alla tensione dialettica che s’istaura tra opposti paradigmi passati e presenti: rilievo/progetto, analogico/digitale, tangibile/intangibile. Gli aspetti trasversali dei fenomeni legati alle ontologie che caratterizzano la commisurazione delle componenti e ai sistemi costruttivi, ovvero materiali, culturali e quindi storici, si prospettano come vettori multidimensionali potenzialmente in grado di indirizzare politiche culturali. Visualizzazioni avanzate, fondate sulla riscrittura di antiche storie ossidionali, promettono nel caso studio, di diventare volani per la riqualificazione di aree archeologiche anche di notevole fama.

Proper documentation is fundamental to providing structural health monitoring, damage identification and failure assessment for Cultural Heritage (CH). Three-dimensional models from photogrammetric and laser scanning surveys usually provide 3D point clouds that can be converted into meshes. The point clouds usually contain noise data due to different causes: non-cooperative material or surfaces, bad lighting, complex geometry and low accuracy of the instruments utilized. Point cloud denoising has become one of the hot topics of 3D geometric data processing, removing these noise data to recover the ground-truth point cloud and adding smoothing to the ideal surface. These cleaned point clouds can be converted in volumes with different algorithms, suitable for different uses, mainly for structural analysis. This paper aimed to analyse the geometric accuracy of algorithms available for the conversion of 3D point clouds into volumetric models that can be used for structural analyses through the FEA process. The process is evaluated, highlighting problems and difficulties that lie in poor reconstruction results of volumes from denoised point clouds due to the geometric complexity of the objects.

To better address mechanical behavior, it is necessary to make use of modern tools through which it is possible to run predictions, simulate scenarios, and optimize decisions. sources integration. This will increase the capability of detecting material modifications that forerun damage and/or to forecast the stage in the future when very likely fatigue is initiating and propagating cracks. Early warning outcomes obtained by the synergetic implementation of NDE-based protocols for studying mechanical and fatigue and fracture behavior will enhance the preparedness toward economically sustainable future damage control scenarios. Specifically, these early warning outcomes will be developed in the form of retopologized models to be used coupled with FEA. This paper presents the first stage of calibration and the combination of a system of different sensors (photogrammetry, laser scanning and strain gages) for the creation of volumetric models suitable for the prediction of failure of FEA software. The test objects were two components of car suspension to which strain gauges were attached to measure its deformation under cyclic loading. The calibration of the methodology was carried out using models obtained from photogrammetry and experimental strain gauge measurements.

Cultural heritage’s structural changes and damages can influence the mechanical behaviour of artefacts and buildings. The use of finite element methods (FEM) for mechanical analysis is largely used in modelling stress behaviour. The workflow involves the use of CAD 3D models and the use of non-uniform rational B-spline (NURBS) surfaces. For cultural heritage objects, altered by the time elapsed since their creation, the representation created with the CAD model may introduce an extreme level of approximation, leading to wrong simulation results. The focus of this work is to present an alternative method intending to generate the most accurate 3D representation of a real artefact from highly accurate 3D reality-based models, simplifying the original models to make them suitable for finite element analysis (FEA) software. The approach proposed, and tested on three different case studies, was based on the intelligent use of retopology procedures to create a simplified model to be converted to a mathematical one made by NURBS surfaces, which is also suitable for being processed by volumetric meshes typically embedded in standard FEM packages. This allowed us to obtain FEA results that were closer to the actual mechanical behaviour of the analysed heritage asset.

In the presence of architecturally significant ruins, restoring and disseminating the idea of a testimony that has survived the destructive work of time is a cultural and social necessity that the use of advanced methods and tools allows to communicate in a timely and comprehensive manner. The integration of 3D surveying techniques and digital information production and management processes (graphic and alphanumeric, i.e., geometric information) makes it possible to put in place multifaceted and effective strategies. The article aims at describing the process of data acquisition (using applied photogrammetry) of the remains of a medieval cloister located on the outskirts of ancient Oppido Mamertina (RC, Italy). The use of the acquired point cloud, cleaned and optimised, made it possible to extract suitable orthophotos from which to derive the matrix profiles of the vaulted roof system. The information organisation of the model, which can be queried on time despite the generic level of detail, leads us to meditate on the change taking place in the field of documentation for urban environmental design and maintenance.

Redesigning the ichonographiae carved in the marble table kept at the Archaeological Museum of the Umbrian capital, has a double meaning: (1) to collect what has been examined by experts of Roman topography on a cartographic practice already recurrent at the death of Augustus, (2) observe with a renewed spirit a document of fundamental interest for the history of survey and architectural drawing. There are in fact three horizontal sections meticulously quoted in Roman “feet”: the ground floor of a funerary monument with an outdoor triclino (scale 1:84), the plan of a vegetable garden serving the rustic villa (scale 1: 140) inhabited on the upper level by the caretaker (1: 230).Proceeding from the mathematical analysis to the planimetric vectorization of the monumental complex, the contribution illustrates the reasons and the path that informed the 3D reconstruction. In compliance with a digital practice shared by the scientific communities; the unprecedented interpretation represented an opportunity to explore its potential uses in terms of a renewed communication paradigm.The objective in progress is aimed at raising a frame of meanings around the memory of Imperial civilization, to guide strategies that do not fail to fall on the policies of protection and enhancement of the property studied. The immersive use of models and adequate spaces for collaboration, which have become collectors of information, thanks and by virtue of dedicated servers, lead to the generalization of issues, which, by affecting a wider audience of users, encourage socio-economic programs as well as cultural technicians.DOI: https://doi.org/10.20365/disegnarecon.27.2021.2

The use of 3D modelling, computer-aided design (CAD), augmented reality (AR) and virtual reality (VR) for the acquisition and virtual reconstruction of Cultural Heritage is of great importance in the analysis, study, documentation and dissemination of the past [...]

Thanks to recent technological developments in 3D surveys, computer graphics and virtual reality, new scenarios have been opened for the documentation and enhancement of ancient sculptures. When not totally preserved, sculptures can be digitally reproduced, modified and visualized to simulate their physical or virtual reconstruction in a non-invasive way for specialists or for dissemination aims. The virtual sculptural reconstruction process starts usually from the 3D survey of real fragments, and then continues by integrating missing parts with 3D modelling techniques by means of source evaluation. Along with primary data sources (reality-based model), secondary data sources (photos, drawings and 3D models of similar sculptures) can be directly used in the reconstruction process. This approach has a double advantage of making the reconstruction activities easier and less arbitrary, contributing to a decrease in the degree of uncertainty for the sculptural reconstruction work, also thanks to many iconographic comparisons to ancient copies. Moreover, virtual reconstruction can be easily visualized alongside a scalable rendering system using open-source Web3D apps and platforms, accessing information, 3D models and descriptions in order to enhance the experience of artworks. Inspecting theoretical and technical approaches, this work aims at establishing how primary and secondary data sources can be effectively used in sculptural reconstruction workflows, and how 3D outputs can be applied to implement digital sculptural heritage exploitation for museums and cultural institutions. The statues of Aesculapius and Hygeia from the sanctuary of Isis in Lilybaeum (Marsala, Italy) were chosen as a case study.

Through a non-contact survey methodology, based on image-based techniques, the authors digitally ‘build’ a three-dimensional hypothesis of a monumental complex carved on a first-century AC marble tombstone. Guided by the mathematical rationality recognised in the artefact, the paper illustrates the reasons for the reconstructive choices and then proposes a reflection on the architectural contents. The ultimate goal focuses on the potential use of the digital product, which, thanks to and by virtue of the use of dedicated platforms, promotes strategies that include identity values by superimposing technical, social, and economic aspects. The setting up of collaborative spaces programmed with different strategies can effectively support the cognitive experience by verifying the possibility of “remedying” contents that, in our case, direct the study, dissemination, and protection of cultural heritage according to the most recent UNESCO recommendations.