Architecture heritage's knowledge is fundamental for historical building's safeguard. In fact knowledge is important to prevent damages, for instance resulting from natural events such as earthquakes, in order to manage maintenance, or to plan conservation projects. The issues related to the knowledge's process are so many, and they increase when the building is under protection laws. The knowledge of an historical building is based on several steps: a careful analysis of the building's architectural, historical and constructive characteristics, of the transformations over time - often linked to varied uses or previous restorations - the materials decay and damages study. As recently focused by the "Guidelines for the evaluation and reduction of seismic risk of the cultural heritage aligned with the new Technical standards for construction (D.M. January 14, 2008)" published by the Italian Ministry of Cultural Heritage, in the process of knowledge an important role is given to buildings' description, based on metrical and geometrical survey, a really efficient base of all subsequent analytical steps. Certainly the use of laser scanners facilitate the measurement's phase; however, in everyday practice, there are some problems: related to the context (for example the difficulty of measurements in the presence of metal scaffoldings, due to the excessive noise due to those devices); related to the procedures of surveying restitution (the phase of data post processing requires skilled professionals); last but not least the high costs of the laser scanner and for its maintenance. At the same time, on the market, there are a wide range of digital photogrammetrical techniques, much cheaper and in many cases of efficiency comparable to the laser-scanning ones. Also there is an important development in software industry with multiple applications in the field of cultural heritage, in particular the open source ones that provide the possibility to perform accurate three-dimensional surveying, in competitive times compared to the laser scanning techniques. The paper presents an architectonical surveying experimentation conduced on archaeological ruins and historical buildings damaged by the seismic event of 2009 that hit L'Aquila. The research unit realised a procedure to achieve a 3D textured model, in particular useful when was diffused some invasive scaffoldings that disadvantaged the use of laser scanners. As digital photogrammetry software, was used the free software Autodesk "123d catch". Surveying data obtained by photo-modelling techniques, before their integration in complex model of the whole building, was post processed with "Meshlab" open source software (developed by CNR's ISTI, Institute of Science and Technology Information of the National Research Council of Italy). In this way digital photogrammetry favoured architectural apparatus and decorative details to the 3D surveying, also related to the materials decay and structural damages. The 3D textured model is itself a tool for building's analysis; in addition it can be imported into GIS to realize Architectural Informative Systems, helpful for a careful knowledge. At the same time it can support the restoration process: virtual restoration can prefigure volumetric re-integrations and works on the macroscopic surface degradation.
Surveying for conservation: test procedures and open source instruments for archaeological artefacts and historical buildings modelling
I Trizio;
2012
Abstract
Architecture heritage's knowledge is fundamental for historical building's safeguard. In fact knowledge is important to prevent damages, for instance resulting from natural events such as earthquakes, in order to manage maintenance, or to plan conservation projects. The issues related to the knowledge's process are so many, and they increase when the building is under protection laws. The knowledge of an historical building is based on several steps: a careful analysis of the building's architectural, historical and constructive characteristics, of the transformations over time - often linked to varied uses or previous restorations - the materials decay and damages study. As recently focused by the "Guidelines for the evaluation and reduction of seismic risk of the cultural heritage aligned with the new Technical standards for construction (D.M. January 14, 2008)" published by the Italian Ministry of Cultural Heritage, in the process of knowledge an important role is given to buildings' description, based on metrical and geometrical survey, a really efficient base of all subsequent analytical steps. Certainly the use of laser scanners facilitate the measurement's phase; however, in everyday practice, there are some problems: related to the context (for example the difficulty of measurements in the presence of metal scaffoldings, due to the excessive noise due to those devices); related to the procedures of surveying restitution (the phase of data post processing requires skilled professionals); last but not least the high costs of the laser scanner and for its maintenance. At the same time, on the market, there are a wide range of digital photogrammetrical techniques, much cheaper and in many cases of efficiency comparable to the laser-scanning ones. Also there is an important development in software industry with multiple applications in the field of cultural heritage, in particular the open source ones that provide the possibility to perform accurate three-dimensional surveying, in competitive times compared to the laser scanning techniques. The paper presents an architectonical surveying experimentation conduced on archaeological ruins and historical buildings damaged by the seismic event of 2009 that hit L'Aquila. The research unit realised a procedure to achieve a 3D textured model, in particular useful when was diffused some invasive scaffoldings that disadvantaged the use of laser scanners. As digital photogrammetry software, was used the free software Autodesk "123d catch". Surveying data obtained by photo-modelling techniques, before their integration in complex model of the whole building, was post processed with "Meshlab" open source software (developed by CNR's ISTI, Institute of Science and Technology Information of the National Research Council of Italy). In this way digital photogrammetry favoured architectural apparatus and decorative details to the 3D surveying, also related to the materials decay and structural damages. The 3D textured model is itself a tool for building's analysis; in addition it can be imported into GIS to realize Architectural Informative Systems, helpful for a careful knowledge. At the same time it can support the restoration process: virtual restoration can prefigure volumetric re-integrations and works on the macroscopic surface degradation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
