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ABSTRACT:The HBIM of the Basilica di Collemaggio in L'Aquila is part of the restoration project of the building seriously damaged by the earthquake in 2009. The project "Ripartire da Collemaggio", funded by ENIservizi, involves an interdisciplinary group called to work together toward a common goal: the need of security of the structures and the need of conservation of the architectonic value of the Basilica. Starting from the photogrammetric and laser scanning survey, interpretation and modelling were needed to create a detailed HBIM to manage the phases of analysis, simulation of structural behavior, economic evaluation of the project, and final restoration. This paper described the generation of the HBIM and its use in the on-going restoration project with a particular attention to the procedures used to preserve the complexity given by photogrammetric and laser scanning data.

ABSTRACT:The paper illustrates the utility to switch from a 3D content model to a Historic Building Information Modelling (HBIM) in order to support conservation and management of built heritage. This three dimensional solution is based on simplified parametric models, suitable for industrial elements and modern architecture, that can be usefully applied to heritage documentation and management of the data on conservation practices. In this sense, the potentials in starting the definition of an HBIM targeted library are investigated, towards the logic of object data definition, beginning from surface surveying and representation. In order to motivate the opportunity in using this 3D object modelling instruments, some case studies are investigated in the paper. Vault and wooden bean floor analysis show how a HBIM for architectural heritage could be implemented in order to assemble different kind of data on historical buildings, such as e.g. dimensional, geometrical, thematic, historical and architectural information.

This paper presents an innovative procedure to create parametric building information modelling (BIM) objects from point clouds of complex architectural features. BIM technology requires an advanced parametric representation of the geometry involving spatial relationships, constraints and material properties. The aim of the procedure is a BIM-based reconstruction methodology that preserves the level of detail encapsulated in photogrammetric and laser-scanning point clouds, and relies on non-uniform rational basis splines (NURBS) curves. The particular case of architectural objects with irregular shapes is addressed due to the lack of commercial BIM software able to handle such buildings. An actual case study made up of 7Á5 billion points is discussed to demonstrate the use of the proposed procedure with huge point-cloud datasets.

<p>The dissemination of the tangible and intangible values of heritage building represents one of the most important objectives in the field of Digital Cultural Heritage (DCH). In recent years, different studies and research applied to heritage monuments have shown how it is possible to improve the awareness of the architectural heritage through the integration of latest developments in the field of 3D survey, 3D modelling, Building Information Modeling (BIM) and eXtended Reality (XR). On the other hand, this digital workflow requires a huge amount of data sources and a holistic approach to reach a high level of information sharing coming from different disciplines and sectors such as restoration, geomatics, 3D virtual museums and serious gaming. In conjunction with entertainment software and gaming, this research shows the main results obtained during the generative process of digital environments oriented to improve the level of information and to enrich the contents coming from the informative models. The case study is represented by one of the most important Lombard monuments: the Basilica of Sant’Ambrogio in Milan. This study, starting from the 3D survey and the data collection of the historical records of the church, improves the creation of an XR experience that reaches a new level of interactivity for different types of devices (desktop, mobile, VR headset) and users (experts, non-experts).</p><p><strong>Highlights:</strong></p><ul><li><p>Generative modelling requirements and novel grades of generations (GOG) and accuracy (GOA) are presented in order to improve the digitisation of built heritage from the 3D survey, reducing time and costs of the scan-to-BIM process.</p></li><li><p>The holistic value of generative modelling allows experts to create digital worlds able to faithfully and accurately represent the detected reality and improve new immersive environments for Virtual Reality (VR) and Augmented Reality (AR) projects.</p></li><li><p>Immersive environments are created with a mixture of the latest generation software and hardware, allowing users to discover the hidden historical values of built heritage with new levels of interactivity and information.</p></li></ul>

The research presented here is the result of two related theses, carried out in collaboration between PoliMi, (Italy) and NTUA, (Greece). Part of it is carried out within the INTERREG EU project framework, which aims to the valuation and dissemination of the role of the Church of S.Maria di Scaria (Vall' Intelvi) in the international European exchange of skills in the past centuries. It mainly focuses on the Carloni's intervention (XVIII century), a local family of craftsmen, famous across many European cities and regions for the construction of monuments with rich decorations. In this way they managed to send holy gifts and money, but also offered their skills in order to enrich the church of Scaria as a symbol of their success. The laser scanning and photogrammetric surveys have been carried out with the on-site stratigraphic analysis and with the quest for the scarcely available historical documents, in an attempt to study the reconstruction and the main transformations and chronological phases, from the Romanic to the Baroque interventions and to the more recent ones: An integrated BIM approach has been chosen as an experimental way of transmitting a piece of the history of the church life to the local people and also for touristic purposes. In order to disseminate the information on the transformations of the building and on the various decorations in a way that would facilitate the readability and interpretation of the monument by the visitors, a little local museum, co-funded by the EU Interreg programme, is planned to be realized mainly containing the exhibition of the collections of the sacred vessels and furnishings donated to the church in the past. To enhance this aim a 3D object modeling will also be exposed in the multimedia section of the museum. A Heritage Building Information Modeling (HBIM) has been developed, while investigating the potential of an object library specially generated to illustrate the various structural elements, the multiple construction technologies for the walls, the vault system, the roof etc., and the decorative layers (frescos, stuccos and frames), along with the critical aspects faced by standard BIM in a complex geometry shift from Surface approach to Object modeling. The research contributes to the explanation of the sequence and construction technologies adopted for the vault system, the first two vaults of the nave (their interesting texturing and the particular geometry registered by laser scanning related to the hypothesized centering), with respect to the vault covering the altar and the apse. The HBIM approach development is analyzed to help the generation of a vocabulary and an abacus of elements to be geographically referenced across Europe to disseminate typical construction elements and skills.

Abstract:The research presented here is carried out within the INTERREG EU A Historic Building Information Modeling (HBIM) has been developed while investigating the potential of an object library specially generated to illustrate the structural elements, the construction technologies, and the decorative layers, along with the critical aspects faced by standard BIM in a complex geometry shift from surface approach to object modeling. The research contributes to the explanation of the sequence and construction technologies adopted for the vault system, the first two vaults of the nave, with respect to the vault covering the altar and the apse. The HBIM approach development is analysed to help the generation of a vocabulary and an abacus of elements to be geographically referenced across Europe to disseminate typical construction elements and skills.

In December 2012, EniServizi (the Italian multinational energy company), after the Earthquake that occurred at L'Aquila in April 2009, decided to undertake the project BRe-start from Collemaggio^, funding around 14 million Euro to restore the Basilica di Collemaggio. EniServizi, aware of the BIM potential role in the complex building and infrastructure domain in the world, required an advanced HBIM based on laser scanner and photogrammetric surveying to address decisionmaking processes among the different actors involved in the preservation process. The Basilica of Collemaggio has been reopened to the public on December 2017. This paper tries to make a synthesis of the different lessons learnt, in relation to both positive and critical aspects relating HBIM feasibility, sustainability and usefulness to the challenging restoration and preservation field. The theo-retical and practical HBIM approach here tackled overcomes the current BIM logic based on the sequential process adopted by the AIA and NBS Level of Development (LOD), characterized by a simple-to-complexdetailing process, working in the new construction domain and generally following the conceptualizing phase, the preliminary design, the executive design, the construction phase till to the facility management. A complex-mixed LOD approach, able to entail the richness, unicity and multiplicity of each component and to get the maximum degree of knowledge, has been experimented in order to derive informed decisions in terms of preservation, restoration and management since the starting phases of the architectural design. To this aim, a Level of Geometry (LOG) coherent to the Level of Accuracy gained by the high-resolution surveys has been adapted to the specificity of the restoration process of a historic monument and is here proposed through different Grade of Generation (GOG) protocols developed in the object modelling to support the preliminary and definitive design proposal of the conservation plan of the Basilica. Particularly, a NURBS-based parametric generative modelling process (GOG9-10) is here proposed in order to get models BBIM abled^ to describe the complex geometry and to match the related information. Specific Level of Information (LOI) has been introduced to support the preservation process, to document the as-built and the management of the building after the intervention, moving HBIM toward multi-actor domain. Given the effort required by such approach, obtaining a cost-effective HBIM modelling embodying the complexity of each damaged element as acquired by the surveys (i.e. walls, pillars, vaults, beams) represents a challenging issue. The result of the overall process aims to contribute in lowering the initial HBIM modelling costs by deploying a sustainable complexity delivering protocols and specification and by boosting at the same time an interop-erable cooperative HBIM habit among multi-actors across all the phases, spreading its usability after the restoration process. On