M. Ioannides et al. (Eds.): EuroMed 2014, LNCS 8740, pp. 290–299, 2014. © Springer International Publishing Switzerland 2014

Between the Fragment and the Atlas: A Device for the Visualization and Documentation

of the Cité de l'Architecture et du Patrimoine in Paris*

Fabrizio Gay1 and Matteo Ballarin2

1Università IUAV di Venezia, Department of Architecture and Arts, Dorsoduro 2196, 30123 Venice, Italy

fabrizio@iuav.it 2Università IUAV di Venezia, Department of Architecture, Preservation, Construction,

Dorsoduro 2206, 30123, Venice, Italy mballarin@iuav.it

Abstract. Cultural Heritage is always a project (even in reference to the past) and could be specifically expressed in the form and manner of the use of display interfaces for the visualization and documentation located by heritage sites. in fact, well-established techniques of visual representation in the history of visual media are part of our Cultural Heritage as well: from drawings to movies, and including the form of iconographic atlases. The legacy of these practices of representation can be embodied by augmented reality devices in the heritage sites: this approach requires a visual interface -and the order of its inte-ractions- to be organized through subsequent levels of spatial, morphological and semantic competence of its final user. Here we propose some guidelines for the design of an integrative display device conceived in connection with the case study of the cité de l' architecture et du patrimoine in Paris, France.

Keywords: Augmented reality, Atlas, tablet, representation, Visual semiotics.

1 Introduction

Premises. Starting with the topic, we soon decided to clarify its cultural features ra-ther than focusing on the the many technical aspects that the issue implies. We would hereby like to discuss the essential features of an interaction device consistent with the legacy of the cultural representation of architecture and the city.

Cultural Heritage is not merely a collection of individual assets of tangible or intangi-ble cultures – text, places, practices, rituals- physically stored and preserved for the bene-fit of future generations; it is, above all, a series of relationships established every day between these different objects: between texts and places, places and practices and so on. This happens in order to actualize their memory, their value, uniqueness or specificity.

* Although the result of common reflections, paragraphs 2 and 3 are by Fabrizio Gay, 1 and 4

by Matteo Ballarin.

Between the Fragment and the Atlas 291

Cultural Heritage is always a sort of “design of memory”, a “retrospective project” for a cultural identity that grows and redefines itself day after day. It is a vast semiotic process [1] whereby values are translated into texts, objects, practices and rituals while, in paral-lel, a different translation from one medium to another happens. Material artifacts, pictures, inscriptions, digital models, movies: a translation between images stored on different physical stands and intended for different practices of reception

For the above mentioned reasons, it is helpful to understand Cultural Heritage from the point of view of the Anthropology of Images [2] and organizational semio-tics, studying concrete practical situations in which it is actually implemented and perceived, observing the specific devices and display interfaces installed at a given site, the techniques of representation and the semantic organization of information. For example, each interaction-design for display interfaces in museums and archaeo-logical sites appears as a valuable opportunity to define both a theory and a practice for cultural heritage.

The effectiveness of the transmission of cultural heritage depends on the practice of its reception. The design of display-interfaces is thus not a matter of engineering, but a sort of bricolage, a kind of stage-direction; it relies on an ad hoc design, in which cognitive and cultural instances are more important than the technological ad-vancement of the subtended devices. This kind of design demands a qualitative shift in order to act as a substantial “retrospective project” which corrresponds to the double -and contradictory- urge for memory and unavoidable oblivion pushing for a new destination.

Case Study. For various reasons, the Cité de l' architecture et du patrimoine in Paris offers us an example of an institution where different visible forms of the transmis-sion of a specific cultural heritage can be compared

1 ) It has been the place devoted to the institutional representation of French arc-hitectural heritage in its relations with the visual arts for more than A century;

2 ) Its location -the Palais de Chaillot- in front of the Tour Eiffel plays a meaning-ful role in the Parisian urban scene;

3) It displays a stratification of different representational media: (architectural models, full-scale plaster casts, drawings, building material samples... );

4) It is the subject of the succession of different projects of transmission of archi-tectural culture and offers a unique layering of different museum forms (collection of plaster-casts, maquette gallery, library, archive...);

5 ) It addresses a manifold audience showing different skills, from professionals to amateurs;

6) It has the explicit institutional function of “actualizing” a constant representa-tion of assets and, therefore, the invention of an image of an architectural and urban “tradition”. Whilst inventing a tangible image of the built heritage, the Cité de l' Architecture et du Patrimoine in the Palais de Chaillot connects the expressive values of given representational media with expressive architectural and urban values. It is an ideal laboratory in which to study and experiment with different forms of transmission of the national architectural and urban culture. Therefore, the opportunity to define guidelines for an integrative exhibition-project through simple devices of augmented

292 F. Gay and M. Ballarin

reality allows us to explain -in the frame of an an action research- a theory of the re-presentation of architecture and the city. Thesis. The design of an augmented reality interface for the cité allows us to stratify different traditional representational practices for space and the built environment in a single tool. To be efficient and effective this interface must correspond to the cogni-tive skills and cultural needs of its various users. We propose a sequential order of skills from the user (spatial orientation of the body to semantic categorization of forms) for the device's activities. These skills should relate to the traditional genres of representations of architecture and of the city. it is fundamental to reconstruct the dif-ferent layers of media -fragment, object, digital model, drawing, painting, movie, broadcasting, video game...- through which an idea of the city is built. The success of the project depends on its capacity to respond both to specific cognitive (natural) de-mands and cultural (semiotic) issues, thus offering the user a new image for Cultural Heritage.

2 Place as a Visual Device

The main aspect of the aura of a place is represented by the mythologies that inhabit it, especially those that create A universally recognized visual device. The Trocadero area is a paradigmatic case, as Roland Barthes remarked on the Eif-fel Tower: in his Mythologies (1964): “Like man himself, who is the only one not to know his own glance, the Tower is the only blind point of the total optical system of which it is the center and Paris the circumference [...] the Tower acquires a new power: an object when we look at it, it becomes a lookout in its turn when we visit it.” [3] The effect of this mythical device of visuality is amplified with the arrangement of the Musée national des Monuments Français (later transformed into the Cité de l' architecture et du patrimoine) in the adjacent Palais de Chaillot, which, in turn, pro-vides an overview of the architectural history of the city and France.

2.1 A Museum as a Monument of Monuments

The Musée national des Monuments Français (MMF) was born after the French Rev-olution in order to "bracket" all the whole monumental iconography of catholicism and of the monarchy. the fragments of the monumental architectural model–displaced and exhibited in a museum space- became simple case studies in AN architectural and sculptural morphological timeline, as in the occurrence of the original Musée de sculpture comparée, conceived by Eugène Viollet-le-Duc - among others- and opened in 1882 in the current location. The previous building for the 1878 World Fair WAS doubled by the Palais de Chaillot's Carlu wing in 1937 [4].

What was left from the previous exhibition-concept was conceived by the direc-tor of the 1930’s, Paul Deschamps, as a small "architectural compared to sculpture" museum. The new conception of MMF as a permanent exposition of sculpture and wall-paintings – understood as the figurative and plastic complements of an architec-tural space – is the result of this 80-year long interpretation of the museum.

Between the Fragment and the Atlas 293

The new name of Cité de l'Architecture et du Patrimoine in 2007 established the completion of this conversion in which the notion of "monument" – a device related to the definition of a figurative national identity – is overtaken and makes room for the definition of Heritage (patrimoine) understood as a sort of “Gross National Prod-uct” of the architectural national culture throughout its history.

The oldest form of plaster casts repository - seen as a theater of architectural ma-quettes, as a wunderkammer consisting of hyper-realistic copies of frescoed walls- constitutes a legacy of the current assets. This happens through the widespread read-ing of a philological principle that understands historical collections as works in themselves, endowed with documentary evidence for History to come.

The MMF is now conceived as a "museum of the museum" [5]; its spaces have been quite reduced in its current architectural and exhibit format (Jean-François Bodin architect, 1995-2007) to make room for a gallery of modern and contemporary archi-tecture (second floor of the Carlu wing). The exhibits in this new galley run from the model of 1850's London Crystal Palace (carefully matched by the view of the real Eiffel Tower, framed by the museum's windows) to more recent architectural achievements.

The museum still retains its character of a 'monument of monuments', in prosecut-ing its aim of describing the monuments of French architecture from the 12th to the 20th century in the form of a sesquipedalian anthology atlas of life-sized plaster casts, copies of sections of monuments and their respective architectural models (in differ-ent dimensional scales and degrees of abstraction), thus constituting a crowded inte-rior landscape, covering more than 20,000 square meters. Any integration within the exhibit project must therefore face itself with the main stake of MMF: its persistent updating as a "monument of monuments." Its main strength from this point of view lies in its theatrical character that involves the visitor within exhibition galleries seen as a kind of “contended space”: ghosts of cathedrals, chapels, abbeys, churchyards, fortified towns, old neighboUrhoods, design studios (atelier) are exposed in a sort of modern Wunderkammer.

2.2 A Museum as an Atlas of Architectural Models

The enhancement of MMF towards the integration of new sections and different kind of exhibits has been its main museological goal. As a museum of architecture, the question is raised of how to deal with dimensional and scalar issues, considering the wide array of fragments and scale models on display.

Architectural models thus became a sort of common ground for the museum's ex-hibits: especially after the opening of the new gallery of twentieth-century architec-ture showing the collections of the Centre d'Archive from the Institut Français d'Ar-chitecture, arranged in a long line of tables arranged through various kinds of objects and display media (drawings, scale models, pictures, interactive 3D models, books and documents...). This collection of recent scale-models is contiguous with the oldest collections of maquettes in plaster and wood that were partially exposed since the Nineteenth Century primarily as didactic supports to the adjacent classes of the Ser-vice des Monuments Historiques and the École du Chaillot.

294 F. Gay and M. Ballarin

The attention to the display and presentation of scale models was then improved during the following years, according to the trend to create stronger links between the two didactic sections of the École (painting and sculpture) and the didactics of archi-tecture. This tendency is based on an idea of Paul Deschamps’ and was meant to es-tablish a common background for visual and geometrical correlation between carto-graphic representations, photographs and maquettes [4].

However, the display of these historic architectural model collections never mate-rialized in the way desired both by Deschamps and by all succeding directors, in par-ticular by Philippe Chapu, whose dream in the 1980's was to create sequences of models at the same scale.

Chapu wanted to exhibit the full corpus of architectural models in large compara-tive series, as was the case of the Nineteenth Century collection of plaster models, in a uniform 1:133,33 scale [6] relating this approach to the great typological exempla of diocesan French architecture from the 11th to the 16th century that Anatole de Baudot had put together, to the collections of wooden structural models ranging from the 12th to the 16th century that Henri Deneux made between 1916 and 1929 [7], and to the series of plaster models expressly manufactured for the MMF until 1970 [8].

Forms of the geometric interrelation between models of the same building at dif-ferent scales were made instead. In particular, one should remember a small plaster scale model of the old mural painting gallery, in the gallery itself,,showing the posi-tion of the paintings in the 1:1 room.

Both reproductions – at 1:1 and reduced scale – were neatly parallel with each oth-er. The scale model and the real room – showing copies of original frescoes – were similar and in similar places – one should say homothetic – and allowed for comforta-ble viewing in a double register: a direct view of the wall paintings and an indirect vision of the full, reduced, gallery.

3 The Introduction of a Device for Augmented Reality

The problem of controlling the orientation of an observer in relation to the maquettes on display could be faced through the use of augmented reality devices, providing tablet computers that allow a geographically positioned exploration of a given historic building. This happens through a digital model linked to the plaster cast or fragment shown in the museum galleries, without having the current display of the whole Cité de l'architecture et du Patrimoine changed.

3.1 Visitor's Spatial Competences and Skills

The visitors’ inherent cultural skills (one has to consider the ways in which geome-trical and physical forms are oriented) are particularly important in the design of inter-faces. The risk involved in producing “decreased reality” tools starts when the viewer (observer) is deprived of the sense of his own body in relation to the material objects he/she is experiencing in their optical and tactics values.

Between the Fragment and the Atlas 295

The anthropological point of view shows how the experience of exploring the opti-cal and kinetic issues of exhibition spaces occurs in defined practical set-ups, accord-ing to given cultural protocols. Moreover, this experience is based on a specific inter-est of the museum-visitor who – according to his/her personal interests – enhances the space and the path in different ways. A classic model for a similar issue – although applied to a different context – has been developed by the semiotician Jean-Marie Floch to the typologies of travellers and their behaviour in the Paris Metro system [9].

Four extreme “types” [9] were investigated: i) "sleepwalker", ii) "professional", iii) "flaneur" (a sort of slacker), iv) '"explorer", depending on the respective ways in which the space is enhanced in terms of: i) continuity, ii) non-discontinuity, iii) non-continuity and iv) discontinuity. These models of personal behaviours correspond to different ways in which the traveller is mapping his/her space, privileging topological rather than topographical issues; continuity or fragmentation; analogies with geo-graphical rather than anatomical spaces.

These considerations play an explicit role in the case of a Museum of Architecture such as the Cité de l'Architecture et du Patrimoine; the observer is constantly pushed to negotiate his/her "inner orientation" in its rooms, in a space replenished with dispa-rate objects. In our case, the visitor must be understood as a kind of flaneur who may change his/her interest when moving freely through the exhibition galleries. His/her explorations must necessarily start from a "zero degree", where his/her physical body happens to be at the same scale of the exhibit. Starting from the construction of a triple coincidence between exhibited fragments, their digital reproduction, the body of the observer, every visitor (even inexperienced ones) can then access richer contents via the device, achieving an exploration of a real iconologic atlas.

One must therefore distinguish three subsequent situations and modes in the inter-

face use: mode 1) a situation in which the visitor/observer moves through the gallery space

using the tablet as a potentially empty frame, observing a given physical model; mode 2) a situation in which a motionless visitor/observer explores a 3D digital

model, delegating his/her point of view to an avatar, using the tablet as a desktop en-vironment;

mode 3) a situation in which the visitor/observer navigates all the linked informa-tional content in a large hypertext meant as an iconographic atlas

3.2 The Structure of the Interface

Although the emphasis here seems to be exclusively on the tablet computer, this de-vice would act as a simple display showing the source of A few input and commands transmitted to a server. In this case, the actor playing the most onerous role is the set of connected servers transmitting a continuous stream of information to the tablets supplied in the museum.

This server 1) interprets the commands sent from the visitor's tablet, 2) detects the position of each tablet in relation to a given exhibited object, 3) processes the images and data sent to each tablet. The server system should thus be able to detect the position

296 F. Gay and M. Ballarin

of the observer (ie. the tablet) in real time (about 15/20 times per second) and to relate IT to a series of digital models. It is thus possible to combine part of the real environ-mental image - detected from the tablet device- with a synthetic counterpart imagery merged in a virtual space matching the same point of view.

The software on the tablet would only be responsible for a) transmitting any re-quirement from the visitor to the server, b) the management of images taken from its camera and, c) displaying an HTML page with a graphic content from the server.

Fig. 1. A schematic articulation of the proposed device. The example refers to the cast of the Tympanum of Saint-Pierre Portal of the Moissac Abbey Church (Tarn-et-Garonne, 11th C.).

Mode 1. In the first situation the observer, through a QRcode positioned on the exhibit, 'hooks' onto a digital model: screen data and visualizations are limited to that particular model, until further notice. This model is perceived as geometrically "congruent" with the displayed fragment or cast. In this case the visitor/observer moves around two overlapping fixed objects (the fragment and its geometric virtual model). A perspectival view depends on the precise location and orientation of the tablet device and it is calibrated to an average focal distance.

When the distance between the body of the observer and the 1:1 scale digital model perspective is not altered, one would have the opportunity to explore virtually the building and a small piece of the surrounding city as well. She/he can move a section plan and then watch the models as if the buildings themselves were subjected to an

Between the Fragment and the Atlas 297

axial tomography. The motion of a virtual section could also relate to time issues, producing images related to the assumptive past and future states of A given built environment.

The situation changes only by varying the focal distance; in that case one gets into a different (critical) situation perceived by the observer as a departure from the virtual model, not connected anymore to the physical exhibit via a series of focal points. In this circumstance, the digital model is perceived as geometrically homothetic (incongruent) according to a real -not colliding- fragment (the eye is the center of this homotety).

Mode 2. At a later (and opposite) stage of exploration, a switch to a dissociated mode of view from the observer's position is expected: the mode becomes entirely interac-tive. The viewers delegate their gaze to an avatar, they begin an exploration of an "anatomical" kind, using the skills that this sort of representation involves at least in two ways:

- the representation of the given building is necessarily taken according to the ref-erences in the observer's body (frontal, sagittal, medial, distal, and from a close-up)

- the representation of the building is conceived so as to describe a referent body that is only partially observable, as in traditional anatomical representations. This kind of representation filters different objects through similarities by other means, such as: a) the scale of reduction, b) the degree of abstraction or detail, c) its fictive colouring and the way in which the object is dissected and ‘flayed’ in the layering of its succes-sive levels of constitutive units.

Mode 3. In the above mentioned alternatives, the perception of A mutual arrange-ment of observer and object does not substantially change as in the previously quoted homoteties. Nevertheless, the setting of hotspots at various locations in the exhibited object (scale model, plaster cast, drawing...) can provide access to further information in different formats: audio, video, texts or images. Here the situation changes drasti-cally and allows access to three different performative areas.

a) a possible comparison with other models in the museum, thus creating a virtual expanded exhibition and marking the access to a mode of exploration that can be de-scribed and arranged in the form of an iconographic and/or iconological atlas (in the wider sense);

b) the interaction and collaboration between visitors, allowed to share images and conversations (including lectures and guided tours);

c) a reuse of already used multimedia products for internal or domestic use; this is possible through the saving and sending of information.

3.3 Digital Models and Image Formats

The same digital model is thus acting as depository of all the possible information (images, sounds, databases...) but the screen format still constitutes an essential ques-tion for the overall direction of the project. A photo-realistic image could not be the best option for visualization, if compared to a wireframe model or a textured surface and, of course, the degrees of iconicity of the image should be negotiated with the exposed object, without disturbing a certain economy of overall 'hallucinosis'

298 F. Gay and M. Ballarin

These considerations are not meant to evaluate the standard formats of 3D model display: one could for example conceive of a hybrid solution, in which the optical image is directly embedded or superimposed on synthetic images from the model.

This can facilitate the passages from an "anatomical" exploration to an "environ-mental" one, using:

- a section of the model with a section plane moving in a given direction; - a selective translucency of surfaces that have been ordered according to a given

paradigm, such as: building typology, architectural order, structural issues... - the combination of direct analogical and optical images with default backgrounds

such as cylindrical or semi-spherical panoramas. It is clear that the issue of image size is quite relevant in every case: as an example,

a complete image of a virtual building (always exceeding the area of the real frag-ment/cast) will be continuously visible even if largely out of the screen-window.

It is necessary that the average focal length can provide reasonable overlaps of the stimuli; we believe that only this difficult, almost illusionistic, condition can provide additional degrees of freedom to the visitor/observer. She/he will be thus able to dele-gate his or her point of view towards an avatar in anatomical or iconographical explo-ratory modes.

The modes of iconographic and iconological exploration turns the tablet computer into a veritable atlas in which the semantic organization of information follows a cat-egory order that is similar to the one adopted by Aby Warburg in his Bilderatlas Mnemosyne [10]. Here the categories assume the status of "family resemblances" (us-ing the definition of Ludwig Wittgenstein).

4 Conclusion

These overall choices – responding to the “stakes” of the museum - will determine the characteristics of the model; such decisions will, of course, have some repercussions in the concrete economic possibilities of technical surveys and staging of physical models. An ergonomic, cognitive and semiotic economy of output must match the inherent input economy, according to the wider range of available techniques.

The Parisian case-study thus requires that one starts from the last issue, laying down the requirements of different outputs and choosing the most efficient inputs, according to the issues of historic building survey and digital modeling. This paper is intended to exemplify the particular decisions always required in the processes of integration of augmented reality in traditional museum environments.

Of course, the design of interaction-oriented devices in museum environments has been one of the main focuses both in Museum studies and in Digital Humanities in the last decade. It acts as a sort of counterpoint to the extensive spreading of museums in Europe and to a wider interest from increasingly specialized audiences.

This spreading of new devices for augmented reality visualization involves: 1) a higher level of ambivalence between the practical and social statuses of "museum" and "theater", 2) the simultaneous presence of images and shapes in a different, coex-istent and enhanced “mode of presence” 3) a museological project and the design of display interfaces overlapping each other.

Between the Fragment and the Atlas 299

In conceiving new visualization devices applied to museums one can follow two opposite paths; the first understands new media as advocates of a totally “new” image [11], bodiless and storyless; the second considers all the images as equipped with body and story: a body in which ancient and modern media and their protocols of use are layered over each other. We adopt this second point of view, according to the pre-cepts of Anthropology of Images [2]. Augmented reality here incorporates video-games, movies, photography, painting, drawing;

Therefore we somehow try to reconstruct the link between the current tablet com-puter and the wooden panel (tavoletta, in italian) Filippo Brunelleschi introduced as a device for representation in the Western visual arts. [12].

The use of these new devices requires skills that are traditionally associated with conventional media: the ability to produce its own avatar, a proper "audience posi-tion", the self-orientation through the production of reference models, the ability to recognize different kinds of figuration and images underlying different geometrical statuses.

References

1. Fontanille, J.: Pratiques sémiotiques. Presses universitaires de France, Paris (2008) 2. Belting, H.: Bild-Anthropologie: Entwürfe für eine Bildwissenschaft. W. Fink, München

(2001) 3. Barthes, R.: A Barthes reader. Hill and Wang, New York (1982) 4. Pressouyre, L.: Le Musée des monuments français: Cité de l’architecture et du patrimoine.

N. Chaudun Cité de l’architecture et du patrimoine, Paris (2007) 5. Cogeval, G.: Une révolution de Palais (1995) 6. AA.VV.: Exposition universelle de 1900, à Paris (Palais du Trocadéro). Catalogue des ex-

positions des monuments historiques (ministère de l’instruction publique et des beaux-arts) et de l’exposition des édifices diocésains (ministère de l’intérieur et des cultes). Impr. de Chamerot et Renouard, Paris (1900)

7. Mayer, J.: Henri Deneux un précurseur. Les Charpentes du XIe au XIXe siècle: typologie et évolution en France du Nord et en Belgique, pp. 279–335. Éditions du Patrimoine, Paris (2002)

8. Mayer, J.: Les maquettes en plâtre du Palais de Chaillot. Monum. Rev. Sci. Tech. Sous-Dir. Monum. Hist. 54–59 (1998)

9. Floch, J.-M.: Sémiotique, marketing et communication: sous les signes, les stratégies. Presses universitaires de France, Paris (1990)

10. Didi-Huberman, G.: Atlas ou Le gai savoir inquiet. les Éd. de Minuit, Paris (2011) 11. Manovich, L.: The language of new media. MIT Press, Cambridge (2002) 12. Gay, F.: An objectual Theory of the representation between Tabula and Tablet. In:

Carlevaris, L., Filippa, M. (eds.) Praise of Theory. The Fundamentals of the Disciplines of Representation and Survey, Gangemi, Roma, pp. 89–94 (2012)