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3D printing has seen a recent massive diffusion for several applications, not least the field of Cultural Heritage. Being used for different purposes, such as study, analysis, conservation or access in museum exhibitions, 3D printed replicas need to undergo a process of validation also in terms of metrical precision and accuracy.<br> The Laboratory of Photogrammetry of Iuav University of Venice has started several collaborations with Italian museum institutions firstly for the digital acquisition and then for the physical reproduction of objects of historical and artistic interest. The aim of the research is to analyse the metric characteristics of the printed model in relation to the original data, and to optimize the process that from the survey leads to the physical representation of an object. In fact, this could be acquired through different methodologies that have different precisions (multi-image photogrammetry, TOF laser scanner, triangulation based laser scanner), and it always involves a long processing phase. It should not be forgotten that the digital data have to undergo a series of simplifications, which, on one hand, eliminate the noise introduced by the acquisition process, but on the other one, they can lead to discrepancies between the physical copy and the original geometry. In this paper we will show the results obtained on a small archaeological find that was acquired and reproduced for a museum exhibition intended for blind and partially sighted people.

In recent decades, 3D acquisition by laser scanning or digital photogrammetry has become one of the standard methods of documenting cultural heritage, because it permits one to analyze the shape, geometry, and location of any artefact without necessarily coming into contact with it. The recording of three-dimensional metrical data of an asset allows one to preserve and monitor, but also to understand and explain the history and cultural heritage shared. In essence, it constitutes a digital archive of the state of an artefact, which can be used for various purposes, be remodeled, or kept safely stored. With the introduction of 3D printing, digital data can once again take on material form and become physical objects from the corresponding mathematical models in a relatively short time and often at low cost. This possibility has led to a different consideration of the concept of virtual data, no longer necessarily linked to simple visual fruition. The importance of creating high-resolution physical copies has been reassessed in light of different types of events that increasingly threaten the protection of cultural heritage. The aim of this research is to analyze the critical issues in the production process of the replicas, focusing on potential problems in data acquisition and processing and on the accuracy of the resulting 3D printing. The metric precision of the printed model with 3D technology are fundamental for everything concerning geomatics and must be related to the same characteristics of the digital model obtained through the survey analysis.

This research is focussed on the analysis of the potential of a close range aerial photogrammetry system, which is\ud accessible both in economic terms and in terms of simplicity of use. In particular the Go Pro Hero3 Black Edition and\ud the Parrot Ar. Drone 2.0 were studied.\ud There are essentially two limitations to the system and they were found for both the instruments used. Indeed, the frames\ud captured by the Go Pro are subject to great distortion and consequently pose numerous calibration problems. On the\ud other hand, the limitation of the system lies in the difficulty of maintaining a flight configuration suitable for\ud photogrammetric purposes in unfavourable environmental conditions.\ud The aim of this research is to analyse how far the limitations highlighted can influence the precision of the survey and\ud consequent quality of the results obtained. To this end, the integrated GoPro and Parrot system was used during a survey\ud campaign on the Altilia archaeological site, in Molise. The data obtained was compared with that gathered by more\ud traditional methods, such as the laser scanner. The system was employed in the field of archaeology because here the\ud question of cost often has a considerable importance and the metric aspect is frequently subordinate to the qualitative and\ud interpretative aspects.\ud Herein one of the products of these systems; the orthophoto will be analysed, which is particularly useful in archaeology,\ud especially in situations such as this dig in which there aren’t many structures in elevation present. The system proposed\ud has proven to be an accessible solution for producing an aerial documentation, which adds the excellent quality of the\ud result to metric data for which the precision is known

Commission V, WG V/2 KEY WORDS: laser scanner, multi image photogrammetry, UAV, point cloud, cultural heritage, earthquake. ABSTRACT:The last few years have marked an exponential growth in the use of electronic and computing technologies that opened new possibilities and new scenarios in the Geomatic field. This evolution of tools and methods has led to new ways of approaching survey. For what concerns architecture, the new tools for survey acquisition and 3D modelling allow the representation of an object through a digital model, combining the visual potentials of images, normally used for documentation, with the precision of a metric survey. This research focuses on the application of these new technologies and methodologies on sensitive areas, such as portions of the cities affected by earthquakes. In this field the survey is intended to provide a useful support for other structural analysis, in conservation as well as for restoration studies. However, survey in architecture is still a very complex operation both from a methodological and a practical point of view: it requires a critical interpretation of the artefacts and a deep knowledge of the existing techniques and technologies, which often are very different but need to be integrated within a single general framework. This paper describes the first results of the survey conducted on the church of San Geminiano in San Felice sul Panaro (Modena). Here, different tools and methods were used, in order to create a new system that integrates the most recent and cutting-edge technologies in the Geomatic field. The methodologies used were laser scanning, UAV photogrammetry and topography for the definition of the reference system. The present work will focus on the data acquisition and processing whit these techniques and their integration.