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3D Model for the documentation of Cultural Heritage: the wooden domes of St. Mark’s Basilica in Venice
No full textTransmission of cultural heritage through time and space by digital 3D models
No full textThe article would refers some interesting experiences of the research team Larifo, BEST Department,
Politecnic of Milan, Italy, in the field of cultural heritage digitalization about the creation of archives and
tridimensional representations which are finalized to the knowledge, the documentation and the fruition of
the artistic and architectural heritage. We will see how it’s possible to create 3D models sculptures of
medium size (i) with the application of laser scanning method and the integration of photographic/
photogrammetric survey to fit out virtual spaces wherewith show rebuilding hypothesis of places or past
events, (ii) to document restoration, allow the reversibility of interventions during the time and (iii) to
realize digital copies which are accessible through web navigation. On the following pages we will discuss
about the acquisition modalities, the modeling and the visualizations used in three different projects that
have significant buildings of Mantua and Sabbioneta, both of them heritage of humanity by 2008, as
intervention sites. The purpose is to demonstrate the applicability of TLS systems and the importance of
digital 3D models in the processes of knowledge, management and valorization
Tecniche di acquisizione e di modellazione di soffitti lignei: conoscenza analitica dei fenomeni di dissesto
No full textIl pavimento musivo della Basilica di San Marco a Venezia: ortofoto digitale 3D a grande scala a supporto dell'attività di tutela, di progetto e di cantiere
No full textProcessi di conoscenza della forma. Il rilievo tridimensionale delle dodici erme di Palazzo guerrieri
No full textA range based method for complex facade modelling
No full text3d modelling of Architectural Heritage does not follow a very well-defined way, but it goes through different algorithms and digital form according to the shape complexity of the object, to the main goal of the representation and to the starting data.
Even if the process starts from the same data, such as a pointcloud acquired by laser scanner, there are different possibilities to realize a digital model. In particular we can choose between two different attitudes: the mesh and the solid model. In the first case the complexity of architecture is represented by a dense net of triangular surfaces which approximates the real surface of the object. In the other -opposite- case the 3d digital model can be realized by the use of simple geometrical shapes, by the use of sweeping algorithm and the Boolean operations. Obviously these two models are not the same and each one is characterized by some peculiarities concerning the way of modelling (the choice of a particular triangulation algorithm or the quasi-automatic modelling by known shapes) and the final results (a more detailed and complex mesh versus an approximate and more simple solid model). Usually the expected final representation and the possibility of publishing lead to one way or the other.
In this paper we want to suggest a semiautomatic process to build 3d digital models of the facades of complex architecture to be used for example in city models or in other large scale representations. This way of modelling guarantees also to obtain small files to be published on the web or to be transmitted.
The modelling procedure starts from laser scanner data which can be processed in the well known way. Usually more than one scan is necessary to describe a complex architecture and to avoid some shadows on the facades. These have to be registered in a single reference system by the use of targets which are surveyed by topography and then to be filtered in order to obtain a well controlled and homogeneous point cloud of the complex architecture.
From the point cloud we can extract a false colour map depending on the distance of each point from the average plane. In this way we can represent each point of the facades by a height map in grayscale. In this operation it is important to define the scale of the final result in order to set the correct pixel size in the map.
The following step is concerning the use of a modifier which is well-known in computer graphics. In fact the modifier Displacement allows to simulate on a planar surface the original roughness of the object according to a grayscale map. The value of gray is read by the modifier as the distance from the reference plane and it represents the displacement of the corresponding element of the virtual plane. Similar to the bump map, the displacement modifier does not only simulate the effect, but it really deforms the planar surface. In this way the 3d model can be use not only in a static representation, but also in dynamic animation or interactive application.
The setting of the plane to be deformed is the most important step in this process. In 3d Max the planar surface has to be characterized by the real dimension of the façade and also by a correct number of quadrangular faces which are the smallest part of the whole surface. In this way we can consider the modified surface as a 3d raster representation where each quadrangular face (corresponding to traditional pixel) is displaced according the value of gray (= distance from the plane).
This method can be applied in different context, above all when the object to be represented can be considered as a 2,5 dimension such as facades of architecture in city model or large scale representation. But also it can be used to represent particular effect such as deformation of walls in a complete 3d way
Generation of a Spatial Information System for architecture with laserscanning data
No full textABSTRACT:
In architectural and cultural heritage documentation, laser scanning technology today offers several opportunities to approach the
object to study and to extract manifold information levels from it. These account for point-clouds, 3-D models, and other data about
the state of conservation. Georeferenced point-clouds can be adopted as the spatial framework of a Space Information System for
Architecture, integrating all spatial information acquired by TLS, photogrammetry, geodetic surveying and direct survey, but also
from other investigation techiques (e.g. GPR, thermal cameras, etc.). Such information system allows to make assessments that are
important for the classification of structural elements or for the determination of the state of decay or preservation of each
architectural element. With reference to the survey of two wooden domes of San Marco Basilica in Venice (Italy), the completion of
the 3-D model of their complex structure is presented here through the description of its main stages, i.e. data acquisition,
registration and modelling. The final 3-D model is then assumed as a 3-D database which clarifies the shape, the composition, the
state of conservation and the structural function of the wooden beams of the domes
scanner analysis and morfological transformation of environmental anthropized sites: the case study of Governolo’s ancient dams
No full textProcessi di analisi della forma: superfici digiali a confronto nel processo della conservazione
No full textLa conservazione degli apparati architettonici e decorativi della "Scala Santa" nel complesso del Palazzo Ducale in Mantova
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