Marco Giorgio Bevilacqua

Frescoed Vaults: Accuracy Controlled Simplified Methodology for Planar Development of Three-Dimensional Textured Models

In the field of documentation and preservation of cultural heritage, there is keen interest in 3D metric viewing and rendering of architecture for both formal appearance and color. On the other hand, operative steps of restoration interventions still require full-scale, 2D metric surface representations. The transition from 3D to 2D representation, with the related geometric transformations, has not yet been fully formalized for planar development of frescoed vaults. Methodologies proposed so far on this subject provide transitioning from point cloud models to ideal mathematical surfaces and projecting textures using software tools. The methodology used for geometry and texture development in the present work does not require any dedicated software. The different processing steps can be individually checked for any error introduced, which can be then quantified. A direct accuracy check of the planar development of the frescoed surface has been carried out by qualified restorers, yielding a result of 3 mm. The proposed methodology, although requiring further studies to improve automation of the different processing steps, allowed extracting 2D drafts fully usable by operators restoring the vault frescoes.

A knowledge-based approach for the structural assessment of cultural heritage, a case study: La Sapienza Palace in Pisa

The full knowledge of the morphological evolution of an historical masonry building, defined more as ‘structural aggregate’ than as ‘single construction’, together with the analysis of the architectural, structural, geological and geotechnical aspects, allow the assessment of the static safety and seismic vulnerability of the complex and the design of retrofit interventions. In the present paper, a Knowledge-Based-Approach is applied to the historical building ‘Palazzo La Sapienza’ in Pisa, allowing to provide reliable results concerning the actual structural condition of the building avoiding the strong computational effort usually associated to the execution of refined numerical analyses. In case of complex buildings, characterized by a high heterogeneity of materials, structural typologies, geometries and so on, the adoption of a global model is not always useful to represent the effective structural behaviour. The proposed approach shows how a deep multidisciplinary knowledge of the construction can limit the use of cumbersome numerical modelling and analysis, however reaching reliable and accurate results usable also in the current practice.

Digital Technology and Mechatronic Systems for the Architectural 3D Metric Survey

Over the last decade, we have seen the widespread use of digital survey technologies that have made the three-dimensional (3D) metric survey within reach of all. In the past, lengthy training was needed to use total stations and classical photogrammetry. Today, laser scanning and “new photogrammetry” allow operators with little training to produce 3D models with high spatial density in real time. These systems have therefore made 3D metric survey available to a wide audience of professionals, and have also allowed surveys to be performed with little economic investment in instrumentation. Although this evolution in survey methodologies has certainly brought great benefits, the use of these methods by operators with limited training poses some risk. The proliferation of imprecise processed 3D data, however, constitutes a digital archive of documentation which, by its nature, should be semi-automatically integrated. Issues related to reference systems, scale of representation, accuracy, and related metadata therefore become highly relevant. This paper aims to describe, by means of several case studies, the laser scanner and “new photogrammetry” survey methodologies in light of the aforementioned issues. In addition, the use of “new photogrammetry” in combination with UAV systems will be presented. The integration and miniaturization of positioning systems, attitude measuring systems, and survey instruments (cameras, laser scanners, thermal and multispectral cameras, etc.) allow, by drone flight, the creation of 3D surveys, something that was impossible several years ago without a substantial budget for the use of conventional aircraft.

Orbetello, a fortress on the water. A research for the valorization of the city and its bastioned front.

Orbetello is located in the Southern Tuscany, at the centre of a lagoon. Founded by the Etruscans, its strategic position it has been disputed for centuries by the major European powers until 1559 when it became the capital of the small Spanish State of Presidios. From that moment, the urban fortifications were continuously subjected to modifications and updates, until the final layout in the 17th century. The current state of general neglect and the recent urban expansion of the city have greatly compromised the integrity of these fortifications. This paper intends to report the results of a research that, starting from an in-deep historical analysis, aims to define some guidelines for the recovery of the city walls and their historical value in a wider project of urban regeneration.

The Triangular Fortress of Butrint, Albania. New studies for the conservation and the valorisation

An important programme of valorisation of the architectural heritage involved the Triangular Fortress in Butrint, in Albania, nowadays UNESCO World Heritage Site. The little knowledge on this supposedly 15th-century Venetian fortress represented a stimulating task for a research, which started with the architectural survey of the structure. Finding information on the time of construction was challenging, the few written books and essays being hardly compatible and lacking confirmation. Therefore, a research was carried out in the State Archives and the Museo Correr Library in Venice, which unveiled unpublished manuscripts and drawings, casting new light on the fortress. On the base of this study, it is now possible to suppose that the Ottomans erected the fortress after 1655. The archive founds, together with the results of the survey analysis, helped also to depict a plausible sequence of the historical phases of construction until its damaging in 1798.