Drones are becoming essential in the field of heritage surveying, especially for large-scale archaeological site. The precision offered by the new survey tools (UAVs, sensors, processing software, etc.) should make it possible to obtain enough information to complete the plan of a site on an urban scale.This paper shows the use of two types of sensors embedded simultaneously on a UAV with the aim of highlighting information that is often difficult to detect on the ground. By crossing RGB and thermal data, certain built-up limits seem to appear. Thanks to this new information, hypotheses of the urban structure are proposed. In other words, the aim is to bring out circulation hypotheses within a large complex archaeological site. Unlike the field of architectural survey where thermography is widely used, for example, to identify certain building pathologies, in archeology this technique does not seem to be part of the traditional survey pipeline and even less on large-scale sites. The possibility of using a third type of sensor is also sketched. The aerial-GPR would in fact make it possible to confirm the presence of a buried structure without having to go through systematic excavation and could provide a three-dimensional image of the ruins.

A survey, defined as a succession of stages ranging from acquisition to representation, has historically an ambition of analysis, understanding, and knowledge representation of architectural artefacts. However, there is a paradox. While for many years this discipline has seen a development in digitization methods and techniques, the purpose of the survey seems to mainly focus on the metric representations of building, and on the production of beautiful (or figurative) images. Acquisitions by lasergrammetry or photogrammetry bring in a quantity of data that are qualified as massive, but appears to be too often underlooked. The present paper attempts to consider work acquisition beyond the ambition of the acquisition of measurements, which investigates new methodological approaches for the characterization of architectural shapes according to different scales of observation. To understand whether the data resulting from the acquisition work can assist "beyond the visible" in the study and analysis of built heritage, this paper addresses three methodological avenues, which relates to the morphological / semantic characterization of architectural objects according to different nature and scale, to consider new methods of analysis by using further massive data.

Cet article a pour objectif d’apporter une réflexion méthodologique sur l’exploitation des numérisations d’un site archéologique de grande échelle. Basées sur un grand volume de données issues de relevés photogrammétriques et GPR aériens, ces numérisations sont bien souvent utilisées pour l’enregistrement de l’état du bâti au moment de l’acquisition ou la prospection archéologique. Notre approche propose d’étendre l’exploitation de ces types de données massives afin d’enrichir la connaissance des logiques de conception urbaine d’une « cité » dont il ne reste que certaines parties monumentales encore visible aujourd’hui. En outre, les méthodes d’analyse urbaine s’appuient largement sur une compréhension occidentale de la ville qui est parfois très éloignée de celle que l’on rencontre en Amérique du sud avant l’arrivée des conquistadors. Au-delà des enjeux de connaissances spécifiques au terrain d’étude, l’ambition première de cet article est de comprendre comment l’apport et l’exploitation des technologies présentes et futures en matière de numérisation patrimoniale pourraient nous aider à accroître notre connaissance du passé. En somme se projeter dans le futur pour opérer un retour vers le passé.

By articulating terminology, functional logics and geometrical logics, the semantics of an element can be considered as an architectural concept. In many ways, architectural semantics is one of the foundations of architectural theory, essential for understanding stylistic evolutions in time and space. At the crossroads of architectural theory, art history and even survey practices, architectural vocabularies offer efforts to provide semantic standardisation that might be revisited today, in the light of recent scientific advances in the field of the built heritage. This article aims to reconcile the cognitive issues specific to the semantic study of architectural elements and the exploitation of big data resulting from building digitisations. It is necessary to compare the geometrical characterisation of a corpus of elements (resulting from the examination of the geometrical similarities shared by this corpus) with the description given by four architectural vocabularies. The challenge is to observe the encounters, but also the points of tension between a semantics proposed by the history of art and a semantics resulting from fine geometrical observations. By highlighting the contradictions between the vocabularies themselves and the geometric model, this article discusses the contribution of methods of analysis coming from computer graphics for the development of architectural knowledge.

By articulating terminology, functional logics and geometrical logics, the semantics of an element can be considered as an architectural concept. In many ways, architectural semantics is one of the foundations of architectural theory, essential for understanding stylistic evolutions in time and space. At the crossroads of architectural theory, art history and even survey practices, architectural vocabularies offer efforts to provide semantic standardisation that might be revisited today, in the light of recent scientific advances in the field of the built heritage. This article aims to reconcile the cognitive issues specific to the semantic study of architectural elements and the exploitation of big data resulting from building digitisations. It is necessary to compare the geometrical characterisation of a corpus of elements (resulting from the examination of the geometrical similarities shared by this corpus) with the description given by four architectural vocabularies. The challenge is to observe the encounters, but also the points of tension between a semantics proposed by the history of art and a semantics resulting from fine geometrical observations. By highlighting the contradictions between the vocabularies themselves and the geometric model, this article discusses the contribution of methods of analysis coming from computer graphics for the development of architectural knowledge.

Le patrimoine culturel recouvre une realite complexe. Il capte l’ensemble des problematiques de son epoque. Il est le lieu ou ne cessent de s’articuler des enjeux normatifs, sociaux, politiques, epistemologiques, ou se reconfigurent en permanence les rapports entre passe, present et futur et ou les echelles varient, du local au global. L’ere numerique, avec les transformations qu’elle induit dans les processus de patrimonialisation comme dans l’etude des patrimoines, accroit cette complexite tout en appelant de nouveaux regards critiques. Telle est la perspective du present ouvrage, qui deplie et deploie deux grandes thematiques. Il aborde d’abord les historicites, les spatialites et les reconfigurations temporelles du patrimoine, puis sa production sociale et enfin les mediations, appropriations et ressentis auxquels il donne lieu. Il traite ensuite de l’articulation entre materialite, immaterialite et dematerialisation, en etudiant cette derniere et ses effets, l’evolution des connaissances sur la materialite des oeuvres, les usages du numerique pour l’acces au patrimoine et sa mediation. Nourri d’un travail collaboratif d’ampleur, il met en lumiere les nouvelles pollinisations entre le monde academique et les institutions culturelles patrimoniales et l’accroissement qualitatif qu’elles constituent. Il montre egalement que l’interdisciplinarite, si elle est concue comme un processus de co-traduction et de co-construction, constitue un formidable levier pour l’avenir de la recherche sur les patrimoines

This paper offers a first methodological look at representing the non-visible in a large scale archaeological site, Pachacamac (Peru). Digitization based on aerial photo-grammetry and ground-penetrating radar (GPR) using an unmanned aerial vehicle (UAV) results in a large volume of data. This data is often used to record the state of a site at the moment of the capture (photogrammetry) or for archaeological prospective (GPR). Our approach proposes to extend the use of such types of big data to gain better knowledge about the logic of urban planning in the context of a heritage study.

L'arrivee du numerique dans le champ des pratiques architecturales et particulierement dans celui de l'etude et de la documentation du fait bâti a engendre ces trois dernieres decennies d'importants bouleversements. A travers une mise en perspective historique et une definition etendue du releve d'architecture, cette recherche vise a discuter et mettre en tension la dimension cognitive propre a sa pratique avec les enjeux technologiques auxquels elle fait face. Sur cette base, un constat s'impose : les empreintes numeriques issues de l'application des methodes d'acquisition les plus recentes (photogrammetrie & lasergrammetrie) expriment une forte exhaustivite (visuelle et metrique) avec les artefacts releves mais produisent egalement d'importants volumes de donnees. Cette surcharge d'informations ne permet pas ou peu de renforcer la representation architecturale dans son role de vehicule de connaissances.Face a ce deficit d'intelligibilite, l'ambition de cette these est de fournir une reponse epistemologique permettant de considerer ce besoin d'intelligibilite sans tourner le dos a la richesse des numerisations produites. Nous proposons ici une approche originale de bas niveau (non-interpretative), ou la signification des elements (structure semantique et geometrique) provient de l'etude des similarites morphologiques observees au sein d'un corpus de formes. L'analyse statistique et le recours a differents descripteurs morphologiques ont permis de formaliser des signatures caracteristiques du corpus etudie ; il s'agit ni plus ni moins de l'expression formelle d'un nombre determine d'attributs geometriques. De maniere plus profonde, notre demarche fournit une solution methodologique pour le traitement de donnees massives. En s'appuyant sur le cumul de donnees, ce travail offre une reponse analytique complementaire aux approches traditionnelles de haut niveau (interpretatives) ou la caracterisation de la forme s'appuie sur les connaissances pre-structurees du domaine. Si l'un des enjeux consiste a appliquer les methodes d'analyse geometrique aux donnees massives, l'autre est de confronter, par l'etude comparative, les observations de haut et bas niveaux. A travers cette recherche, notre souhait est d'affiner la comprehension des propagations stylistiques dans le temps et dans l'espace. Afin d'experimenter cette approche, 31 colonnes du cloitre de l'Abbaye de Saint-Michel-de-Cuxa ont fait l'objet d'une analyse morphologique approfondie.

For nearly thirty years, the digital phenomenon has integrated many disciplines. Those involved in the image processing and analysis took advantage of this major technological breakthrough to revisit the tools and methods of their discipline. In this context, the architectural field, and more specifically the one of heritage analysis and documentation, have greatly benefited from the development of acquisition and visualization techniques. Today, it is no longer unusual to document a building with millions of three-dimensional spatial coordinates. Whether in the context of archeology, history of art or architecture, digital documentation of built heritage is becoming a major contemporary challenge1. AlICe laboratory (Computer Laboratory for Image and Conception in Architecture) from the Faculty of Architecture of the Université libre de Bruxelles (ULB) investigates this field for many years through a research and education program. In terms of architectural design, the practice of graphic representation firstly involves the definition of an idea by drawing exclusively relevant information. The architect draws only the lines he considers necessary for the transmission of the idea of its project. This “graphical economy” is therefore for the benefit of didactic quality. But what does this issue become when the matter of representation is not the prescription but the description of an architectural object? Until the last century, documentation by drawing corresponded to a work of reverse engineering in which it belonged to the architect to understand the object and to represent its key feature. Today, 3D data acquisition technology promotes an increasingly “figurative” representation of architecture. In this paper, we will try to consider some epistemological avenues for the integration of those new approaches to the requirements of architectural representation through the lens of student’s works.

Over the past few years, advancements in the field of 3D digitizing has increased the fidelity of geometric models. So far and despite of this acuity enhancement, a gap remains between the growth of collected data and its uses as vehicle of knowledge. New challenges have emerged to handle massive content of a 3D footprint. Considering those un-interpreted data as starting point for further investigations, the hypothesis is to rely on a "low-level" analysis of geometric features aiming to enrich informative and scientific value of "high-level" semantic studies. This article describes an approach using discrete curvature assets to link morphological identification and semantic characterization. The mean curvature has been parametrized to highlight it use as an eloquent shape description. At this point, a comparative analysis within an architectural collection composed of similar entities would be led according to the remoteness degree compared to an average geometric reference model. The introduced principle explores the construction of curvature-based signatures so as to reassess the conceptual articulations of 31 Romanesque columns from the cloister of the abbey of Saint-Michel de Cuxa.

ALICE -Laboratoire d'informatique pour la conception et l'image en architecture -est une unité de recherche et d'enseignement de la Faculté d'architecture La Cambre-Horta de l'Université libre de Bruxelles qui traite de questions relatives à l'analyse et à la représentation architecturale par les moyens graphiques numériques.Le laboratoire, qui émerge au beau milieu de l'enthousiasme débridé des années 1990 pour l'avènement du numérique en architecture, se positionne dès le départ en accord avec cette avantgarde qui cherche, dans la spatialité du bit et la cyberculture naissante, une suite logique aux formes fracturées et aux théories de la déconstruction.Le solipsisme dans lequel cette tendance dite « numérique » tendra à se cantonner amènera ALICE à prendre peu à peu ses distances avec les questions de conception, pour se focaliser sur une approche innovante de l'analyse architecturale.Le leitmotiv de cette approche sera une compréhension critique de la représentation graphique, tant par les médias traditionnels que par les médias numériques, et ce, dans un contexte profondément ancré dans la théorie, l'histoire et l'épistémologie.ALICE prend alors le contre-pied de la plupart des laboratoires d'architecture et d'informatique qui investissent généralement des questions exclusivement formelles ou performatives.Son champ d'expérimentation se focalise désormais sur l'analyse, pour la simple raison que cette dernière peut être entendue comme une forme de rétroconception 1 , mais vierge -dans une certaine mesure -d'idéologies architecturales.Au moyen de la représentation graphique, un tel cadre de travail permet ainsi de questionner, de manière détachée, la forme, le contexte, ou encore le processus de conception, ainsi que la représentation graphique elle-même.Ce postulat constitue aujourd'hui la charpente d'une recherche en plein essor et d'un enseignement à la fois éprouvé et innovant, dont les productions font l'objet de publications régulières et dont la renommée internationale est établie.Illustré de quelques exemples, cet article propose une rétrospective sur vingt ans de construction d'une réflexion architecturale originale, dont l'enjeu n'est pas le développement de méthodes instrumentales, mais bien un processus réflexif sur la dimension graphique du discours architectural.

Over the past three decades, the introduction of digital technologies in the field of architectural documentation has profoundly changed tools and acquisition techniques. Most of the developments concern metrical and colorimetric characteristics of the objects studied. These developments, surrounding the practice of architectural survey, tend to respond primarily to the requirements of completeness. In this context, it seems necessary to assess the impact of these instruments on the cognitive value of architectural representation. With a strong technological presence, the study of the built heritage is facing a problem of “information overload.” Indeed, this strong technological presence fails to strengthen representation in its role as a vehicle of knowledge. Confronted with the intelligibility deficit, this article proposes an original approach for reading morphological features of an artifact by using a bottom-up approach: the meaning of elements (i.e., their semantic layouts) come from a statistical analysis of the major shape discontinuities of a collection of instances. The idea is to rely on data accumulation to render apparent high-level semantic structures from the comparative analysis of common low-level geometric features. The principles introduced are illustrated by the study of 31 columns of the cloister of the abbey of Saint-Michel-de-Cuxa. To summarize, the first objective is to understand how digital technologies can help us in the analysis of artistic and technical production of Romanesque columns. The second objective is to automatically identify the common semantic articulations of the entire collection to build a reference model for the future assessment of each artifact.

Three-dimensional representation is becoming an effective support for the documentation of the state of conservation of heritage artefacts, for the study of its transformations and for cultural diffusion. 3D digitization technologies now offer effective means to observe and analyze historic buildings with more accuracy, completeness and timeliness. Nevertheless, this produces a real problem of information overload. The growing mass of un-interpreted data make emerge a need for innovative methodologies assisting data processing, sorting and analysis by researchers who want to use it for advancing the knowledge of cultural heritage. Exploring the informational value of these new representation systems allows introducing new approaches to the analysis of artefacts so distant in space but so close in features typologies, styles, compositional rules, etc.. This chapter presents some research avenues for defining a geometric/semantic description model of architectural elements in order to integrate the informative value of 3D digitization in intelligible representations.