Il BIM per gli edifici storici, potenzialità e criticità. Il caso del Duomo di Parma

L’articolo descrive una ricerca in itinere relativa alla realizzazione di un Historical BIM del Duomo di Parma, finalizzato al restauro e alla manutenzione programmata della fabbrica. Partendo dal rilievo integrato laser scanner e fotogrammetrico, attraverso l’analisi di dati esistenti (geometrici, storici, fotografici, etc.) è stata effettuata la realizzazione di un sistema informativo alla scala architettonica. L’approccio al problema è gestito in ottica BIM, dal momento che questi strumenti si stanno oggi sempre più diffondendo e, grazie anche alle recenti norme nazionali (UNI 11337/2017) e internazionali (EUPPD 2014/24), sono destinati a diventare lo standard di riferimento obbligatorio per tutti i progetti pubblici. Tuttavia, il loro reale utilizzo nel campo dei beni culturali è ancora scarsamente diffuso e i diversi aspetti legati al contributo della geomatica in tale ambito rappresentano grandi opportunità di ricerca. Nel descrivere quindi la metodologia adottata, verranno messe in luce le criticità connesse alla realizzazione di un modello BIM relativo ad edifici storici, cercando di delineare un workflow applicabile anche in altri contesti simili

Integrated survey for architectural restoration: A methodological comparison of two case studies

A preliminary survey campaign is essential in projects of restoration, urban renewal, rebuilding or promotion of architectural heritage. Today several survey techniques allow full 3D object restitution and modelling that provides a richer description than simple 2D representations. However, the amount of data to collect increases dramatically and a trade-off between efficiency and productivity from one side and assuring accuracy and completeness of the results on the other must be found. Depending on the extent and the complexity of the task, a single technique or a combination of several ones might be employed. Especially when documentation at different scales and with different levels of detail are foreseen, the latter will likely be necessary. The paper describes two architectural surveys in Italy: The old village of Navelli (AQ), affected by the earthquake in 2009, and the two most relevant remains in Codiponte (MS), damaged by the earthquake in 2013, both in the context of a project of restoration and conservation. In both sites, a 3D survey was necessary to represent effectively the objects. An integrated survey campaign was performed in both cases, which consists of a GPS network as support for georeferencing, an aerial survey and a field survey made by laser scanner and close range photogrammetry. The two case studies, thanks to their peculiarities, can be taken as exemplar to wonder if the integration of different surveying techniques is today still mandatory or, considering the technical advances of each technology, it is in fact just optional

From survey to analysis for Cultural Heritage management: a new proposal for database design in BIM

The thesis work presents the implementation of a BIM system aimed at maintenance, conservation and restoration of Cultural Heritage. Its main goal is to give a concrete answer to the lack of specific tools required by Cultural Heritage documentation: organized and coordinated storage and management of historical data, easy analysis and query, time management, 3D modelling of irregular shapes, flexibility, userfriendliness, etc. BIM methodology, providing an information system at architectural scale and making it possible to manage semantically enriched three-dimensional models, represents an effective solution for supporting scheduled maintenance and conservation activities (which are an increasing important instrument for safeguard and conservation of Cultural Heritage), on condition that suited tools and functions are made available. The application developed in this thesis started from a BIM system and enriched it with functions to address these goals. In particular, a specifically designed database was implemented, where all data about the historical building can be stored. A tailored database is necessary to organize historical data that generally are not standardized, have a complex structure and are fuzzy in their description. The database is compliant to the currently in-force Italian regulations and allows storing and retrieving information useful for maintenance purposes. The application was implemented with the specific aim of providing tools also for non- AEC experts: it gives user-friendly graphical interfaces to access the data and makes available tools for data entry, element modelling, attribute query and thematic mapping. It works standalone or can be integrated into the main commercial BIM software (at the moment the experimentation has been limited to Revit) or accessed via web. One of the main goals was not to be bounded to a specific software and to make the system usable on a larger scale, by developing a flexible and customizable methodology that can be applied to a wide range of historical assets

Experimental Tests and Simulations on Correction Models for the Rolling Shutter Effect in UAV Photogrammetry

Many unmanned aerial vehicles (UAV) host rolling shutter (RS) cameras, i.e., cameras where image rows are exposed at slightly different times. As the camera moves in the meantime, this causes inconsistencies in homologous ray intersections in the bundle adjustment, so correction models have been proposed to deal with the problem. This paper presents a series of test flights and simulations performed with different UAV platforms at varying speeds over terrain of various morphologies with the objective of investigating and possibly optimising how RS correction models perform under different conditions, in particular as far as block control is concerned. To this aim, three RS correction models have been applied in various combinations, decreasing the number of fixed ground control points (GCP) or exploiting GNSS-determined camera stations. From the experimental tests as well as from the simulations, four conclusions can be drawn: (a) RS affects primarily horizontal coordinates and varies notably from platform to platform; (b) if the ground control is dense enough, all correction models lead practically to the same mean error on checkpoints; however, some models may cause large errors in elevation if too few GCP are used; (c) in most cases, a specific correction model is not necessary since the affine deformation caused by RS can be adequately modelled by just applying the extended Fraser camera calibration model; (d) using GNSS-assisted block orientation, the number of necessary GCP is strongly reduced

HBIM for Planned Conservation: A New Approach to Information Management

HBIM (Historical Building Information System) represents a very promising tool for the management of Cultural Heritage, both for daily operations and for the planned preservation of the asset itself. However, it requires a specific effort to adapt tried and tested tools and methods for new construction to existing Cultural Heritage buildings. First of all, the starting point of the process (new construction projects versus surveys of existing buildings) changes, and consequently the requirements for geometric and informative modelling change. Especially in the field of Cultural Heritage, an in-depth and reasoned design of such (geometric and informative) models is necessary, to respond properly to the needs identified in the processes for planned conservation. To this end, an appropriate semantic classification of the building elements must be carried out prior to modelling, taking into account both documentation and geometric description requirements. The aim here is to propose a system for managing the information component of the model that takes its cue from the internal logic of BIM (Building Information System) Authoring (Autodesk Revit©) software and takes into account the operating practices of professionals in the conservation sector. In particular, a system which no longer takes into account the traditional two-dimensional classification of elements, but which directly affects threedimensional technological elements is proposed. This is the case of the remains of the convent of S. Maria, near Lake Garda, where the geometric modelling was structured according to this new model of management of information content. In this way it was possible to give a complete description of the reality of the building (and its surroundings), making it more usable and readable by the operators

An open-HGIS project for the city of Parma: database structure and map registration

The observation of the structure of the city and its inhabitants, and how such system evolves in time, is essential in almost all land planning and urban development activities, as well as in any historical study. Historical GIS in the last decade proved to be one of the most promising frameworks, that can provide innovative tools and methodological approaches in this field, allowing new research perspective and concept in many fields. The paper describes the early stages of the development of a HGIS that considers different historical periods of Parma (Italy), with particular attention to cadastral documents and associated census data. These data are gathered from the main cadastres of the city: the Sardi Atlas of 1767, the Bourbon Cadastre of 1853, the Post-Unitarian Cadastre of 1901 and the Cadastre of 1940. Other social statistics, conserved in the local communal and state archives, such as census reports, building permits, deeds, transfer of property, wills, etc., were considered in the project, leading to a quite complex database structure. In the hope of making the HGIS as flexible and scalable as possible, and to make the system usable to the widest spectrum of users, an open-source database architecture based on Postgresql/Postgis has been developed. The paper provides information about the database structure and the map registration stages, with particular reference to the first historical period considered in the project, based on the Sardi Atlas (drawn in 1767), which can be considered as the first parcelgeometric cadastre of Parma

Influence of Block Geometry Configuration on Multi-Image Dense Matching

Digital photogrammetry is a widespread surveying technique in different fields of application due to its flexibility, versatility and cost-effectiveness. Despite its increasing automation and simplicity, a proper image block design is crucial to ensure high standards of performance and accuracy. Studies on camera network design have been largely dealt with in the scientific literature with reference to image orientation process, while they are still poor on dense matching. This paper investigates the influence of different block geometry configurations on multi-image dense matching. Starting from the same orientation solution, dense matching was performed considering different combinations of number of images and base length distance between the first and the last image within a strip. The raster Digital Elevation Models (DEM) resulting from each sequence of images were compared with a reference DEM to assess accuracy and completeness. The tests were conducted using different cameras and at various test sites to assess different survey conditions and generalize the findings. The presented results provide some operational guidance on block geometry optimization to maximize the accuracy and completeness