Modelling Medieval Vaults Abstracts

Modelling Medieval Vaults Symposium July 2016 – Abstracts

 

Keynote 1

Benedikt Ried’s Deconstructive Vaults in Prague Castle – Design, Construction and Meaning

Thomas Bauer – Bauer-Lauterbach GmbH

Jörg Lauterbach – Bauer-Lauterbach GmbH

Norbert Nußbaum – University of Cologne

The most prominent contribution of Middle European architecture to the break-up of the visual arts for early modern times are spectacular vault constructions. For ambitious patrons such constructions served as proof of artistic competence, and at the same time they demonstrated their creator’s share in a new scientifically grounded theory on architecture.

In the last decades of the 15th century the contest of the arts had been all about commenting on new ways of visual space perception in micro and macro cosmological dimensions – from Albrecht Duerers portrait of a piece of turf to models of the earth as a globe. In this context, ambitious architects were well advised to open a position in that contest and to demonstrate architecture’s space defining creativity as one of its core capabilities.

The unparalleled virtuosity of the artefacts frequently focused on the potential of the three dimensionally curved line. Thereby the space designers pointed out the specific expertise that they had gained by generating Gothic form systems, whose linearity was a matter of course. Due to its spherical shape and linear-figurative structure the rib vaulted ceiling offered a perfect laboratory for the creation of space wonders, that would adequately visualize the authority of master masons as learned members of the new knowledge society.

Those who wanted to present something really new – in rivalry with the Renaissance architects, who altogether abandoned the Gothic vault – were well advised to break up and dynamize the standard rib formations in their homogenous and ornamental appearance in favorite of surprising and puzzling effects, thus commenting on the uncertainty of space experience and contributing to the new space discourse. In other words: they had to deconstruct the Gothic design doctrine as it had been handed down over generations.

Especially the vault designs of Benedict Ried talk about the rib vault’s liberation from meeting any constructive or functional obligation for the stability of the building. The vault’s new task is rather to visualize the disengagement of space and its material shell, which can rightly be called an emancipatory idea of Renaissance art theory.

The study of deconstructive vaulting design encompasses traditional measurement methods as well as stadia surveying and terrestrial or hand-held laser scanning of rooms and workpieces. The field surveys aim for the reconstruction of the design and building processes with particular regard on the mason’s stone cutting procedures and the carpenter’s  practice of centering and scaffolding. Comparisons between the built stone work and the contemporary treatises on geometry and building practice allow for reflections about the relation between the theoretical and practical side of vault technology.

Rightly considered, these vaults are invitations to analyze its disturbing forms with an inquiring eye and a mind that recaps their making. The question „What is this?“ is to give way to a „How was it made?“. In this sense we try to perceive the deconstructive vaults around 1500 as epistemic objects that are supposed to demonstrate the predominant knowledge of their builders and awarding authorities.

 

Keynote 2

Cracks and distortions in masonry arches and vaults

Santiago Huerta – Polytechnic University of Madrid

The original geometry of masonry arches and vaults is inevitably distorted after the decentring. For a period of years the foundations settled, the buttressing elements move and the supports of arches and vaults are displaced. The only way for the masonry to adapt to these aggressions is to crack, and different cracking patterns can be easily observed in any kind of masonry vaulted construction. Very small settlements would lead to small movements and the cracking could be impossible to discern: the geometry remains almost unaltered. However, in many cases the foundation settlement (or the settlement of the masonry masses) may lead to movements gross enough to be ascertained easily by inspection. This is the case, for example, of the gothic high vaults. The gothic vaults are supported by slender buttresses and a very small uneven settlement of their foundations would lead to a small leaning of the buttress, say of 0.5 degrees. Such an small inclination would produce a displacement in a typical buttress, say of 20 m height, of 175 mm. If both buttress lean the increase of span would amount to 350 mm, or in a vault of a typical span of 10 m, an increase of around 1/30 of the span. Such a great increase would lead to a visible cracking and distortion of both ribs and webs of the vault. If the gothic vault is being surveyed, either for an architect or engineer in an expertise of its stability, or by an architectural or construction historian who wants to ascertain the gothic tracing methods, he or she would need to know the origin and nature of these cracks and geometrical distortions. Any surveyor working nowadays in historic monuments is well aware of this phenomenon: the analysis of the cloud of points, obtained with a precision of millimetres (scanner laser or digital photogrammetry), would be impossible to interpret without considering the mechanics of masonry arches and vaults cracking. The phenomenon was known centuries ago, particularly in the case of very flat arches. It appears that it was the great French engineer Jean-Rodolphe Perronet, at the end of the 18th Century, the first to attempt a scientific study of the cracking and movements of the arch bridges after decentring. Viollet-le-Duc, ca. 1850, studied also in depth this in the context of his expertise on the vaults of the church of Vézelay, and these studies lead him eventually to his theory of the “elasticity” of Gothic vaults (Viollet-le-Duc applied the word to the capacity of adapting to any small movements). It was only in the 1960’s, when professor Heyman developed the modern theory of masonry structures, when, for the first time, the theoretical frame which permitted a rigorous understanding of the “plasticity” of masonry structures. Indeed, professor Heyman studied in depth the cracking of arches, vaults and domes of many types (including Gothic vaults). Masonry consisted of “rigid” blocks, stones or bricks, bonded in some way. It can withstand great compressions but no tension and can easily form cracks. It is precisely this capacity of forming cracks which gives the capacity of adaption of masonry, the “plasticity”.

The present lecture aims to give a basic knowledge of the principles underlying the way masonry arches and vaults crack and distort, that is, to afford the knowledge which an architect, engineer or architectural or construction historian would need to take into account the normal cracking and consequent distortions which are characteristic of masonry arches and vaults, or of any building of unreinforced masonry.

 

Keynote 3

Mixtec Stonecutting Artistry; Documentation and Visualization of Late Gothic Ribbed Vaults in Southern Mexico

Benjamin Ibarra-Sevilla – The University of Texas at Austin

This presentation shows a digital survey approach that merges 3-D data visualization and the underlying principles of stereotomy found in historic manuscripts. The presentation reveals how information obtained directly from historic structures can be scrutinized and analyzed in order to draw conclusions relevant to the original constructive and historic aspects surrounding the buildings.  The underlying string connecting the dots of this project is stereotomy, the science of cutting solids that mediates between the art of construction and geometry. Stereotomy was applied practically on stone structures such as arches and vaults in order to shape stone pieces that secured the stability of the structures. The presentation departs from the understanding that the relationship between shape and gravity is a key component of stability of vaulted structures. Therefore current methods of documentation supported by digital technologies offer useful geometry-based information that is meaningful to achieve a correct assessment of structures such as gothic ribbed vaults and others.

The research project centers its attention on the ribbed vaults of three outstanding early sixteenth-century churches found in southern Mexico. These three buildings are: the church of Santo Domingo Yanhuitlan, the church of San Juan Bautista Coixtlahuaca, and the open chapel of San Pedro y San Pablo Teposcolula, which are located in the region named “La Mixteca” in the State of Oaxaca. The three buildings are superb examples of ribbed vaulting constructed in the Americas during the XVI century. Following the Spanish tradition of late-gothic stereotomy, the ribbed vaults built for these buildings show complex networks of ribs connected by bosses and other elements that suggest that well versed master builders with sophisticated geometric knowledge were in charge of these constructions. Furthermore, the hexagonal plan of the vault covering the open chapel is a unique example in hispanic-american architecture. In summary, the churches are testimony of the achievement of the indigenous master carvers who transformed European building technology into magnificent late-gothic ribbed vaults built with rigorous and refined stonecutting procedures.

The methodology developed in this research project uses digital information obtained from a laser scanner documentation that has been utilized to identify the constructive solutions, the underlying geometry, and the current state of conservation of the three different ribbed vaults. The presentation emphasizes on the methodology and the results of the analytical processes elaborated through the combination of different digital information processing and formats such as point cloud, NURBS, and other modeling techniques. This investigation gives light to the design procedures applied for the vaults’ conception while understanding the underlying principles of their construction. The sixteenth-century vaults used as case studies for this project provide an excellent environment to study the connections between past methods of depiction and construction combined with current technologies revealing these buildings in a way that has not been seen before. The presentation unfolds the complex constructive and stereotomic solutions and processes exploring forms of visualization that aim to educate the general public through different media and methods. Finally, this presentation proposes how application of digital tools can reveal insightful views of the construction technology of the past providing examples that can be used for effective documentation strategies of the future.

 

Digital processes 1

Technical knowledge transfer in European Late Gothic: multi-star vaults

Enrique Rabasa-Díaz – Technical University of Madrid

Ana López-Mozo – Technical University of Madrid

Miguel Ángel Alonso-Rodríguez – Technical University of Madrid

Rafael Martín-Talaverano – Technical University of Madrid

Gothic vaults construction evolved in a different way in each European region, also regarding what is concerned with the rib network design procedures. Determining the spatial outline of a particular vault just from the analysis of its visual appearance or its plan layout is not possible nowadays, and neither would be for a medieval master builder: an explanation or the availability of the original tracings is needed. Thus, in order to distinguish mere copies of a pattern from a deeper relationship, it may be convenient to take into account a geometrical and constructive spatial analysis. We are currently studying technical knowledge transfer in the context of European late Gothic from the analysis of actual geometry of vaults that appear to be similar.

This paper is part of a research that analyses the dissemination throughout Europe of a specific type of vault based on a plan layout configured by two, four or six stars without inner supports. We have identified at least 11 vaults of this group in Spain and 9 in other European countries, as well as several drawings in late medieval and early modern written sources. They form a single spatial volume whose horizontal layout comprises several modules of simple quadripartite or even five keystones tiercerons vault patterns (e.g. Lincoln cathedral’s crossing vault).

Supported by an automated photogrammetric survey, this paper addresses an approach to the ribs network design process for the Spanish cases. The objective is to be able to establish relationships with the rest of the known examples and contribute to support or criticise the existence of a technical knowledge transfer beyond apparent similarities or the documented presence of a master mason in a particular place and time.

Having used other surveying techniques, our research team is currently facing a critical use of digital photogrammetry, concerning both the process of data acquisition and 3D modelling, as well as the latter geometrical analysis. This technique successfully produces models of vaults whose central boss is placed even 50m over the floor. Carrying heavy measurement devices is not needed, although some reference points are required to establish the orientation and size of the model as well as to check the error margin. Such points may be measured by means of topographical devices (total station), but this paper also provides some alternative methods.

 

Medieval vaults for Renaissance architecture: Modelling the vaults on sheet 10 of Leonardo da Vinci’s Code B

Marco Carpiceci – Sapienza University of Rome

Fabio Colonnese – Sapienza University of Rome

In the early 80s of the XV century, the thirty-year Leonardo da Vinci is preparing to leave for Milan. In the sheet 341 of Codex Atlanticus, Leonardo endorses himself at the Sforza court. He asks to be tested and to demonstrate he can “give perfect satisfaction in comparison of any other in architecture, in the composition of public and private buildings, and in moving water from one site to another.” Its intense planning activity is testified by both the documents linking him with the Fabbrica del Duomo and the amount of drawings made during this period. Relevant autographical evidences are located in the Code B at the Istitute de France, which collects most of his architectural designs. Leonardo, who was probably already a recognized architect, used to draw not only to develop his design thoughts but also to accumulate a repertoire of existing valid solutions, so that his manuscripts can be considered a rich compendium of illustrated gothic and Renaissance engineering knowledge. The eight geometric patterns of vaults on a square base Leonardo drew on the recto of sheet 10 in Code B must be analysed in this prospective. They should be related both to the architectural questions open in the Milan cathedral, and to examples he directly or indirectly knew, as well as to his typical attitude to generalize specific design issues in constructive and geometric repertoires. This paper intends to use new digital technologies to foster greater understanding of those vaults patterns. Thanks to the research and reconstruction methods modelling software made available, those designs can be analysed, reconstructed and modelled according to the shape they would have if built. Starting from the two-dimensional representations, through the careful analysis of the ‘signs’ and with the help of existing graphic techniques, the authors have produces three-dimensional solid models consistent to Leonardo’s representation. Where the signs do not give univocal information, suggestions and hypotheses stimulated by their ambiguity must be compared with the late Gothic architectural context in which Leonardo lived. This method of analysis and interpretation, through which the authors are currently processing the entire corpus of Leonardo’s architectural designs in view of the fifth centenary of his death in 2019, goes beyond the mere philological research to land to the concept of hermeneutics, considered as a desire to “disclose” his “hidden” thought. As for every critical activity, this operation has not only an analytical but a proactive value: it provides a model which, although projectively and philologically correct, is mainly a mental exercise to deepen both Leonardo’s thought and architectural knowledge of his age.

 

Morphological and geometric complexities of built heritage

Danilo Di Mascio – Northumbria Univeristy

Built heritage represents a precious material and cultural resource to be studied and preserved for present and future generations. In recent years, constructions pertaining to cultural heritage are increasingly understood, documented, managed, analysed and disseminated through the application of several digital technologies; this trend has created one of the main research areas in architecture, called Digital Heritage. Digital technologies, such as laser scanner, CAAD and 3D modelling software, open up alternative and new possibilities in the study of tangible and intangible features of built heritage. However, they don’t substitute traditional methods and tools but complement and enrich them. The number, variety and flexibility of digital technologies allow to tackle and analyse the high number of (often unique) features that characterize each construction that pertain to built heritage. Every building is constituted by several tangible and intangible characteristics and one of the most important is represented by the morphological ones. Usually, the first contact with a building is visual. If we are not able to understand, represent and document its general morphology, that means shapes and dimensions, we will never be able to analyze its single elements, or to understand the structures that regulates it. The shape of a building can be regulated by a well-defined geometric structure, such as in Gothic cathedrals, or be the result of an irregular arrangement of elements such as in many vernacular buildings. Researches on two case studies, one vernacular and one polite, showing the use of digital technologies in the documentation, digital reconstruction and analysis of built heritage will be presented. The first one is about the Turchinio’s trabocco. The trabocchi are pile-dwelling vernacular constructions used as fishing machines, located along Abruzzo’s coast, Italy. These wooden structures present an apparently random disposition of beams and poles; the fishermen placed them to face basic structural failures of the trabocchi, but using their practical intuition, hence without having any professional structural knowledge. The presentation will show the digital reconstruction and critical analysis of the Turchinio’s Trabocco as a way of increasing the knowledge of the trabocco and generate a series of information to define and manage its maintenance. The second case study is focused on the facades of one of the most important historical street in Newcastle upon Tyne: Grainger Street. The facades of the Victorian and Georgian buildings along the street represent exactly the opposite situation compared to the trabocco: the elements and their overall arrangement in each façade is also the result of a careful geometrical study based on shapes, dimensions and proportions. Laser scanning technologies were selected as an appropriate way to collect the basic data (in this case point cloud data of the whole street) that are being used as the basis to make a 3D digital model of Grainger Street. The digital reconstruction process, still ongoing, is composed by three phases that will be illustrated during the presentation: the organization of the files and facades; the schematic redrawing of the facades; the modelling of the facades and the street.

 

Wells cathedral choir aisle vaults: digital documentation and analysis

Nick Webb – University of Liverpool

The use of digital techniques offers the opportunity to rapidly and accurately document and analyse historic works of architecture, especially in comparison to traditional manual techniques. With this in mind, the research of the nineteenth century scholar Robert Willis into the design and construction of medieval vaults could be augmented and enhanced. This is particularly relevant as Willis was unable to fully prove his hypotheses based on the limitations of manual techniques, for example the process of surveying medieval vaults across several sites, high up in cathedral interiors requiring access by scaffolding, was not viable. In contrast, new techniques such as digital laser scanning allow us to document medieval vaults from the ground relatively quickly, with seemingly reliable results for later analysis.

As a case study we are investigating the choir aisle vaults at Wells cathedral. These have previously been considered as a repeated single design; however, Alex Buchanan has identified visual variations by eye, and will discuss these in detail later in the symposium. However, the extent of the variations observed visually requires a full survey to be carried out for analysis, hence using digital laser scanning. In addition to investigating these potential peculiarities, the choir aisle vaults also offer an opportunity to explore vault design and construction in relation to the research of Willis.

This paper will discuss the methods used to document and analyse the vaults at Wells, starting with two-dimensional analysis by creating orthographic projections from the point cloud models to reveal similarities and differences between vault bays in plan and section. This investigation was then expanded into three-dimensions by tracing digital mesh models along the intrados line of vault ribs, forming the starting point of a detailed analysis exploring each rib’s radii, number of arcs, apex height and the arc’s centre point in relation to the impost line as discussed by Willis.

The paper will also examine the hurdles we faced and what these could mean in terms of our findings. These include the limitations of scanning from the cathedral floor as well as issues of interpretation such as acceptable tolerances when tracing vault rib curvatures; which became our primary analysis method.

 

 

New questions in 14th-century vaulting

Wells cathedral choir aisle vaults: issues of interpretation

Alex Buchanan – University of Liverpool

Following on from Nick Webb’s paper on the methods of data capture, processing and presentation used in relation to the fourteenth-century choir aisle vaults of Wells Cathedral, the aim of this paper is to demonstrate four ways in which this data can be analysed in order to address questions of chronology, design and construction.

The first method involved tabulating and representing measurements derived from the wire-frame models in order to identify patterns and possible correlations. This analysis suggested that the bays can be considered as four separate sets of 3 bays each.

The second method involved stylistic analysis of the boss sculpture, which confirmed the division into four separate sets and suggested a possible chronology for the vaulting, starting in the eastern bays of the south aisle, proceeding to the north aisle which was vaulted from east to west and finishing with the three western bays of the south aisle.

Based on our understanding that the vaults were projected from a tracing floor, the third method involved creating horizontal projections from the models, which were analysed to try to identify the geometrical processes used to create the two dimensional design of that tracing floor. The differences between the projections reconfirmed the existence of four bay sets and suggested a process of tinkering with the design across the first three sets, followed by a radical revision in the western bays of the south aisle.

Finally, we returned to our table of measurements which we analysed in relation to the visual appearance, structural form and practical construction of the vaults in order to try to ascertain the rationale for the differences. The final solution in particular shows clear constructional advantages over the others, but it seems evident that other factors must also have played a part.

Our findings demonstrate that Wells should be viewed as a site of experimentation, at which different design propositions were tested and improved. These experiments reinforce the position of Wells in the historiography of Gothic as a ‘prodigy building’, in which are found developments of significance to the development of late Gothic across Europe. In particular, Wells shows a pioneering use of ribs of consistent curvature, such that the three-dimensional form of the vault becomes dependent upon a single radius, rather than multiple radii being dependent on an a priori decision that the vaults should have level ridges. A number of other design principles also emerge, which will require testing at other sites.

 

Design changes: the macro- and micro-architectural vaults of fourteenth-century collegiate churches

Andrew Budge – University of London

This paper will review, from a formal rather than a technical perspective, the vaults of macro- and micro-architecture erected in the collegiate churches of England and Wales founded in the fourteenth century. The dataset suffers from some losses, most notably Newarke, but still contains some of the most distinctive vaults of the century: on a large scale those at Ottery St Mary, St Mary’s, Warwick, Arundel and Winchester College; and on a smaller scale, such riches as the tomb canopy at Shottesbrooke, the Aerary porch, the Cobham piscina and the Easter Sepulchre at Warwick.

The review will map the frequency with which the various broad categories of vault design (tierceron, simple lierne, complex lierne, net, and proto-fan) were deployed, in order to gain an overview of the observed changes. From this, a number of challenges to prevailing narratives emerge. These include: the selectiveness which characterises the appropriation of features from the Gloucester Abbey vaults; the decidedly conservative approach taken by many ‘metropolitan’ designs; the diversity of vaults used by William Wynford; and, not normally associated with late-fourteenth-century architecture, a shift towards the use of curvilinear conoids and mouchettes.

The paper will conclude by elaborating on key questions regarding the role of technology in the formal changes to the century’s vault designs, the resolution of which would be of considerable interest to architectural historians. To what extent did the availability of technical skills constrain the diffusion of certain vault types, and what were the factors influencing the pool of expertise available?

 

From Two to Three Dimensions: Drawings and Design Processes in Medieval Vaulting

Sophie Dentzer-Niklasson – Courtauld Institute of Art

Medieval masons did not have Auto-CAD and other programmes to plan the erection of vaults three-dimensionally. Yet much had to be planned for the successful erection of a vault. For instance, the junction of ribs and bosses were planned in advance as bosses, with the correct number of ribs and its moulding profiles, were often carved in advance of the construction. This paper will address issues around the design, planning and construction process of vaults in the Middle Ages in regards to drawings and the translation of the rib pattern from two to three dimensions. The design (when architectural forms and elements are decided upon) and the construction (when those forms are erected) were much more interlinked during the Middle Ages than in modern architectural practice, with no distinct separation between theory and practice. There was a general tendency to work out details on the spot. The vault is probably the largest three-dimensional element of a great church, yet the experimentation and establishment of the rib pattern, the first stage of design, consisted of an exercise in two dimensions. I will show that the thought and design processes surrounding the construction of vaults were primarily two-dimensional. Given the scarcity of architectural drawings in medieval Britain, I will rely heavily on Continental examples and scholarship, principally German, to argue that drawings were used in Britain at each stage of the process and that they were essential in transioning the two-dimensional rib pattern to three-dimensions. The implementation of the two-dimensional pattern on a three-dimensional volume was, of course, site specific, and its process closely linked with the erection itself, first with the preparatory work on the tracing floor and then its final execution on the scaffold. By comparing this Continental evidence to British material I will argue that similar design and construction processes were used throughout Europe.

 

Digital processes 2

The Construction of the Vaults of Mallorca Cathedral

Paula Fuentes – Technical University of Madrid

Rosana Guerra-Pestonit – University of Santiago de Compostela

A recent structural analysis required a detailed survey of the vaults and buttressing system of the Cathedral of Mallorca. The new technique of scanner laser has permitted to obtain a cloud of millions of points, both from the intrados and the extrados of the vaults, with a precision of some millimetres. To interpret this enormous amount of data some knowledge of the Gothic construction technique is needed. The joints between the stones are also of some millimetres (say, 5 mm); the imperfections during the erection processes are one order of magnitude higher and we will measure them in centimetres. The unavoidable deformations of the masonry –mainly due to the yielding of the buttresses– are again one order of magnitude higher, of the order of decimetres (in the case of Mallorca 100-400 mm).

The data referring the vaults of Mallorca should be analysed considering the above mentioned facts. Another set of assumptions refer to probable tracing techniques: we will expect the ribs as circle segments –being traced on the floor– to obtain the form of the centres and the templates of the stones. Probably, these arches would spring with a vertical tangent. Perhaps, the particular form of the ribs would be similar (terzo acuto, quinto acuto, etc.). If the surveyor wants to investigate the probable “original” geometry, he would also try several possible geometrical patterns.

As the vaults have deformed and are actually distorted, the surveyor needs to know something about the mechanics of the cracking of masonry arches, where the “hinges” could appear, etc. The analysis involves, then, some knowledge of medieval construction and the theory of masonry structures.

The last step would be to study the geometry of the masonry webs between the ribs. This aspect has been rarely studied. Now, with a dense cloud of measured points, the surveyor may try again reasonable hypothesis, which may or may not be contrasted with physical evidence; in any case, all these assumptions depend on probable erection techniques. It may be that the geometry of the webs was defined by slender wooden beams between the ribs: an analysis of the curvatures of the surface of intrados would reveal in this case a consistent pattern of points of zero Gaussian curvature.

Our work would present the constructive analysis of Mallorca’s vaults trying to give a probable explanation of the original geometry taking into consideration the above mentioned aspects.

 

Comparison of Digital Documentation Methodologies of Neo-gothic Vaulting System : A Case Study of Dominican Church, Ghent, Belgium

Weiyi Pei – KU Leuven

Lui Tam – KU Leuven

While recording and analysing intricate historic vaulting systems are made more convenient due to the advancement of digital technologies nowadays, some characteristics referring to the specific 3-dimensional composition of vaults remain challenges to tackle. How to select the right tools becomes a critical issue to improve the efficiency and accuracy of the documentation. This paper intends to discuss this issue by assessing and comparing different documentation methodologies based on first-hand field work experience.

The subject of study is the Dominican Church in Ghent, Belgium, a Neo-gothic edifice built in 1854. The listed building is mainly constructed of brick, stone and timber. It has suffered from various degrees of moisture related damages, including several key areas on the timber-framed plaster vault ceiling. A proper documentation of the current condition is critical for establishing the intervention plan for its conservation.

Three methodologies were employed to capture the vaulting system of the church, namely total station documentation, 3D laser scanning and photogrammetry. Each method was put into practice and then evaluated based on efficiency, accuracy, and output format.

Total station is capable of capturing precise spatial coordinates to produce accurate metric drawings. This is particularly useful when recording elements with regular geometry. However, when dealing with more organic shapes and curvatures, total station is likely to lose its advantages. Precision of the outcome is directly associated with the number of points captured. In practice, the level of accuracy is drastically reduced concerning more intricate details such as the ribs of the vaults, due to the distance between the total station and the ceiling, as well as the limit of using total station to capture every detail line of the ribs.

Laser scanning can be used to compensate the complexity in forms and to document the surveyed space in a short time. Moreover, data acquisition doesn’t rely on the lighting condition of the site, which makes the method particularly useful for areas with poor or none illumination. However, the output of monochromatic point cloud data is primarily metric, with limited visual information of the building material. Even if RBG data is assigned to each point using the camera embedded in the laser scanner, the resolution of the image is not high enough to produce pathological records.

Photogrammetric point cloud model generated from high-resolution photographs reflects both metric and visual quality of the surveyed components. Unlike laser scanning, the data acquisition process of photogrammetry does reply on the lighting condition of the space. However, quality of the photographs can be guaranteed with the usage of a tripod in combination with proper ISO and aperture. With the control points captured by total station to control the critical dimension of the model, the accuracy of the final model is comparative to laser scanning. Orthographical image generated from the Photogrammetric point cloud is applicable to both dimension extraction and pathological analysis.

In conclusion, in the particular case of the Dominican Church, photogrammetry in combination with total station is the most cost-effective and efficient method to generate both metric and visual record of the site.

 

Role of the “Horizontal ribs” in late gothic vault constructions in Hungary

Gergely Buzás – King Mathias Museum in Visegrád

Balázs Szőke – Pazirik Informatics Ltd

Balázs Szakonyi – Pazirik Informatics Ltd

The examination of several late gothic Hungarian vaults and vault fragments was possible within the framework of the SziMe3D project. The whole laser scan surveying of the Recollect church in the Szeged lower downtown area has been completed. The measurement data could be used for the examination of the geometry of the nave vault, as the vault also suffered damage with the tumbling of the southern wall in Szeged. The combined white light and laser scan surveying of the vault fragments of the former Virgin Mary provostry in Székesfehérvár and the Basilica of Pécs could be included in the programme from among the perished structures. The surveying authenticated the theoretical reconstruction models created beforehand by Balázs Szőke. A virtual tour has also been created from the research results with the work of Pazirik Informatics Ltd. – the company participating in the project. The surveying of stone sculptures of the former Basilica in Eger is also in progress for the research within the framework of the project aimed to display the castle of Eger with the contribution of Pazirik Informatics Ltd. We have digitalized the stone material with 3D photogrammetry technology. The theoretical reconstruction of the vault of the Basilica in Eger has also been created. The projects about to be presented have a common point, these are computer generated reconstructions of late gothic vaults from the end of the 15th century and the beginning of the 16th century that were created with a such a special design procedure, where the master masons had used the composing of “horizontal vault ribs” into the structure. The most significant still standing monuments of this vault type are the nave vault of the Franciscan church in the lower downtown of Szeged and the nave vault of the church in Pukanec /Bakabánya/, Slovakia. The appearance of this vault type in Hungary can be originated from the southern German late gothic architecture, primarily from the surroundings of Burkhard Engelberg. The ideas that could be ascribable to Engelberg are squarely visible on the former vaults of Pécs. The characteristic signs parallel to the creations of Stephen Weyrer known as the apprentice of Engelberg are also visible. The vaults of Szeged and Eger have been created along the design analogical to the apse vault of the Heiligen Kreuz Münster standing in Schwäbisch Gmünd, and can be closely connected to such later creations, as the nave vault of Marktkirche in Halle an der Saale or the apse vault of the church in Schorndorf. The result of the project is the comparability of the presently standing architectural creations with the models of perished vaults and inner spaces, as well as the asserting of the 3D visualizations of numerously perished late gothic Hungarian monuments. The scan surveying can authenticate the models created of the perished structures with the method of “virtual anastylosis”.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A collaborative research project using digital techniques to investigate medieval vault design in the British Isles.