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TopIntroduction
Computer and digital technologies, associated with a higher diffusion and development of Information and Communication Technologies, have led to profound changes in the field of architectural survey and representation. In particular the use of representative digital 3D models has acquired an inescapable role.
An architectural digital representation conceptually cannot be limited to its surfaces – as far as conducted at the highest level of photorealism – or to the problem of measurement’s metric accuracy – as far as necessary –, but inevitably it must also include the issue of understanding, representation and communication of historical and aesthetic characteristics, interpreted in the broadest sense of the terms. Consequently the contents are influenced by: building characteristics (for example a ruin of classical age, a medieval castle, a renaissance palace, a baroque church); specific representation aims (such as geometrical-dimensional surveying, degradation analysis, communication addressed to non-expert users, etc.); last but not least, level of definition (scale or, for a 3D model, the Levels of Details).
Digital technologies favor the representation of architecture by the definition of virtual 3D complex models (Figure 1). In particular these models have to contain not only dimensional and geometrical building’s aspects, but they also have to represents architectural and constructive ones, describe transformations, be a core for the aggregation, organization, analysis, and management of the vast and heterogeneous number of information associated to an architectural heritage – such as surveying and design drawings, historical documents, scientific data (Centofanti & Brusaporci, 2012) .
Figure 1. 3D model of a block of buildings of the historic center of L'Aquila city (Francesca Cerasoli)
TopBackground
An Architecture is a complex organism, synthesis of spaces, surfaces, volumes, materials, made with specific constructive systems, result of processes of transformation and modification over time, expression of interventions and of architectural cultures that have occurred since its construction to the present day. Each building has its own quality of “individual,” for this reason it is often used the term “handmade” (or “artifact”), to highlight how a historic building can be seen as a product of human activity.
Digital technologies have fundamentally altered techniques and tools of surveying and drawing, basing the representation on the three-dimensional model. The debate is concentrated on issues related to the problems of modeling and rendering, necessarily involving disciplinary fields such as computer graphics and topography. A broadly interdisciplinary approach is necessary (for example Cigola, 2012), however, remaining the same problems and objectives set by the critical historical study of architecture, and in particular the need of the use of architectural surveying for the analysis, acknowledgment and communication of historical and aesthetic values (Docci & Maestri, 2009).
In recent years many researchers have been interested in cultural heritage digital representation, in particular focusing on computing issues, often without distinguishing between cultural and architectural heritage.
The themes of cultural heritage survey and 3D modeling have found a place in many international conferences, and are the subject of several associations (http://cipa.icomos.org/; “IEEEXPLORE”; Digital Agenda for Europe of European Commission; Remondino & El-Hakim, 2011; Boehm, Remondino & Kersten, 2013). However, in such cases, specific building heritage’s representation problems are not studied autonomously, but they are analyzed according to those aspects and issues that architecture has in common with other kinds of cultural heritage, such as archaeological ones.
Key Terms in this Chapter
Architectural Virtual Museum: Favors the dissemination of knowledge and the heritage enhancement, correlating, reporting and showing architectures, even distant from each other. In some ways the digital museum can be seen as specific declinations of dedicated digital archive, i.e. of a more general database. In most cases it collects photographs and architectural drawings. The greatest potential is in teaching and tourism. Their capacity is expressed even more in the case of archaeological sites where the models can represent reconstructive hypotheses. Thanks to virtual applications and ICT, perhaps the museums’ encyclopedic approach of the nineteenth century can find a new raison d'être, in particular according to cultural contents of the digital age.
Interpretative Architectural Model: The architectural 3D digital model is the mediator between intellect and tangible reality, and it takes the form of a digital replica of the observable phenomenal reality. Thereby the model expresses – i.e. contains – the history of the building and its passage through time. It’s an interpretable document, but also a genuine critical-historical text, expressed with the figurative language of the virtual dimension. Presupposition of this methodology for historical analysis, it’s a careful architectural surveying, a wise modeling project and an intelligent and critical use of the digital model.
Historical – Critical Analysis: The historical-critical method refers to a set of criteria for the historical and philological study of the architectural heritage: the building it’s intended as a synthesis of modification and transformation that conduced it to the current configuration, results of architectural cultures and interventions that have taken place over time.
Architectural Surveying: The understanding of building characteristics and their appropriate graphical documentation, made by the analysis, selection, synthesis and representation of the architectural event. The survey is formed by the succession of the following steps: a preliminary study and acquisition of documents; the survey design; the measurement; the restitution with interpretative models of reading and communication of the architectural heritage. Only the measurement phase can be considered objective, the others are subjective as influenced in their outcomes on the skills, culture and experience of the surveyor.
Architectural Graphical Analysis: Starting from the Fifties, the use of drawing has been coded for the graphical analysis, that is, referring to the structuralism lesson, drawing is regarded as a meta-language, i.e. a graphical language able to analyze another language, the architecture’s one. Similarly, complex 3D models, thanks to their characteristics of interaction, browsing, inquiring and decomposing, are useful instruments to study and represent structural, figurative and functional aspects of architectural heritage.
Representation of Architectural Heritage: Architectural heritage 3D representation is conceptually related to knowledge, because it’s required the values understanding and their appropriate documentation and representation. Digital models have to describe the buildings, namely a complex system made by spaces, surfaces, materials, constructive technologies and degradation, with modification and stratification processes witnesses of events and cultures that have occurred over time. Therefore, the term “representation” takes a critical widest sense and all-encompassing than the terms “modeling” and “rendering.”
Architectural Heritage Values: The UNESCO 1972 World Heritage Convention, indicates as cultural heritage monuments, group of buildings and sites, outstanding universal value from the point of view of history, art or science. In the modern theory of restoration are identified as values of cultural heritage historical values and aesthetic values. The purpose of the restoration is that of heritage values maintaining (to give them to future generations); therefore necessarily the first act of a restoration consists in the recognition of the values. The values, and in particular the historical values, can be recognized in any historic building; evaluation of the quality of historical and aesthetic values is referred to a critical act of the scholar.
Architectural Artifact: This expression is used to highlight that a historic building can be seen as a product of human activity. This becomes even more important for an historic building, built with artisan technologies and stratified during of his life. Therefore, its material consistency takes on a specific testimonial value of the cultures and transformations that have generated and modified it over time. Additionally, the material characteristics can be used as chronological indicators for dating parts of the building. Hence it follows that it is necessary to put special attention in the study of construction system also in digital modeling.
Architectural Informative System: An instrument for data management and elaboration. GIS have been developed in urban planning, while the first applications to cultural heritage have been made in the field of archeology. The first uses related to architecture were realized by applying the traditional GIS to two-dimensional drawings (plans and sections). Subsequently information systems have been developed using models as a three-dimensional interface: either importing 3D models within GIS or using Building Information Modeling software. The main potentialities of information systems consist of performing correlation and analysis of vast amounts of data that, especially for buildings, have heterogeneous characteristics and different scale of representation. Since this data is related to architecture, the model – in its three-dimensional nature – favors a reinterpretation in terms of space and time.
Architectural Digital Archive: A virtual space in which correlate data, services and users in order to the preservation, use and sharing of information. Digital archives for the architecture collect written / graphics documents, usually dispersed in different collections, according to a strategy as of conservation – for the fragility of the original documents – as of smart access. In particular, digital archives favor historical research and comparative analysis. 3D models can be used working alongside traditional metadata, as an aid to historical-critical analysis of the works – both realized as only planned – and assisting the study of the authors and of architectures in relation to the historical context.