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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Parameterized Shape Grammar for n-fold Generating Islamic Geometric Motifs

Sayed, Zahra, Ugail, Hassan, Palmer, Ian J., Purdy, J., Reeve, Carlton January 2015 (has links)
No / The complex formation of Islamic geometric Patterns (IGP) is one of the distinctive features in Islamic art and architecture. Many have attempted to reproduce these patterns in digital form, using various pattern generation techniques. Shape grammars are an effective pattern generation method, providing good aesthetic results. In this paper we present a novel approach in generating 3D IGP using an extended shape grammar: Parametrized Shape Grammar (PSG). PSG allows a user to generate both original and novel forms of Islamic geometric motifs (a repeated unit of a pattern). PSG is generalized to generate n-fold Islamic geometric motifs in a 3D environment, practically implemented as a 3D modeling tool within Autodesk Maya. The parametrization within each grammar rule is the key to generating numerous original and novel Islamic geometric motifs.
2

[en] MCAD SHAPE GRAMMAR: PROCEDURAL MODELING FOR INDUSTRIAL MASSIVE CAD MODELS / [pt] MCAD SHAPE GRAMMAR: MODELAGEM PROCEDIMENTAL EM MODELOS CAD MASSIVOS INDUSTRIAIS

WALLAS HENRIQUE SOUSA DOS SANTOS 31 July 2018 (has links)
[pt] Modelos CAD 3D são ferramentas utilizadas na indústria para planejamento e simulações antes da construção ou realização de tarefas. Em muitos casos, como por exemplo na indústria de óleo e gás, esses modelos podem ser massivos, ou seja, possuem informações detalhadas em larga escala no intuito de que sejam fontes de informações precisas. Para obtenção de navegação interativa nesses modelos é necessária uma combinação de hardware e software adequados. Mesmo hoje com GPUs mais modernas, a renderização direta desses modelos não é eficiente, sendo necessárias abordagens clássicas como descarte de objetos não visíveis e LOD antes de enviar os dados à GPU. Logo, para renderização em tempo real de modelos CAD massivos são necessários algoritmos e estruturas de dados escaláveis para processamento da cena de forma eficiente. O trabalho dessa tese propõe o MCAD (Massive Computer-Aided Design) Shape grammar, uma gramática expansiva que gera objetos para criar cenas 3D de modelos massivos de forma procedimental. Nos últimos anos, modelagem procedimental tem ganhado atenção para criar cenas 3D rapidamente utilizando uma representação compacta, que armazena regras de geração ao invés de representação explícita da cena. MCAD Shape grammar explora repetições e padrões presentes em modelos massivos para renderização de cenas, reduzindo o consumo de memória e processando a cena procedimentalmente de forma eficiente. Convertemos modelos reais de refinarias em MCAD Shape grammar e implementamos um renderizador para os mesmos. Os resultados mostraram que esta solução é escalável com alto desempenho, além de ser a primeira vez que modelagem procedimental é utilizada nesse domínio. / [en] 3D CAD models are tools used in the industry for planning and simulations before construction or completion of tasks. In many cases, such as in the oil and gas industry, these models can be massive, that is, they have large-scale detailed information in order to be sources of accurate information. Interactive navigation in these models requires a combination of appropriate hardware and software. Even nowadays with modern GPUs, the direct rendering of these models is not efficient, requiring classic approaches such as culling non-visible objects and LOD before sending the data to the GPU. Therefore, for real-time rendering of massive CAD models, we need scalable algorithms and data structures to efficiently process the scene. The work of this thesis proposes MCAD (Massive Computer-Aided Design) Shape grammar, an expansive grammar that procedurally generates objects to create 3D scenes of massive models. In recent years procedural modeling has drawn attention for quickly creating 3D scenes using a compact representation, which stores generation rules rather than explicit representation of the scene. MCAD Shape grammar explores repetitions and patterns present in massive models for rendering scenes, reducing memory footprint and procedurally processing the scene efficiently. We converted real refinery models into MCAD Shape grammar and implemented a renderer for them. Results showed that our solution is scalable with high performance, also it is the first time that procedural modeling is used in this domain.
3

Procedural reconstruction of buildings : towards large scale automatic 3D modeling of urban environments

Simon, Loïc 25 July 2011 (has links) (PDF)
This thesis is devoted to 2D and 3D modeling of urban environments using structured representations and grammars. Our approach introduces a semantic representation for buildings that encodes expected architectural constraints and is able to derive complex instances using fairly simple grammars. Furthermore, we propose two novel inference algorithms to parse images using such grammars. To this end, a steepest ascent hill climbing concept is considered to derive the grammar and the corresponding parameters from a single facade view. It combines the grammar constraints with the expected visual properties of the different architectural elements. Towards addressing more complex scenarios and incorporating 3D information, a second inference strategy based on evolutionary computational algorithms is adopted to optimize a two-component objective function introducing depth cues. The proposed framework was evaluated qualitatively and quantitatively on a benchmark of annotated facades, demonstrating robustness to challenging situations. Substantial improvement due to the strong grammatical context was shown in comparison to the performance of the same appearance models coupled with local priors. Therefore, our approach provides powerful techniques in response to increasing demand on large scale 3D modeling of real environments through compact, structured and semantic representations, while opening new perspectives for image understanding
4

Auto-Parameterized Shape Grammar for Constructing Islamic Geometric Motif-Based Structures

Sayed, Zahra, Ugail, Hassan, Palmer, Ian J., Purdy, J., Reeve, Carlton 29 June 2016 (has links)
Yes / The complex formation of Islamic Geometric Patterns (IGP) is one of the distinctive features in Islamic art and architecture. Many have attempted to reproduce these patterns in digital form, using various pattern generation techniques, in 2D. Shape grammars are an e ective pattern generation method, providing good aesthetic results. In this pa- per we describe a novel approach in generating 3D IGP using the shape grammar method. The particular emphasis here is to generate the motifs (repeated units with the pattern) in 3D using parameterization. These can then be manipulated within the 3D space to construct architec- tural structures. In this work we have developed two distinctive Shape Grammars in 3D namely Parameterized Shape Grammar (PSG) and Auto-Parameterized Shape Grammar (APSG). Here the PSG generates the motifs and the APSG enables construction of the structures using the generated motifs. Both grammars are practically implemented as a 3D modelling tool within Autodesk Maya. The parameterization within each grammar is the key to generate both Islamic geometric motifs and Islamic geometric motif-based structures.
5

Vers la modélisation grand échelle d'environnements urbains à partir d'images / Towards large-scale urban environments modeling from images

Moslah, Oussama 05 July 2011 (has links)
L'objectif principal de cette thèse est de développer des outils pour la reconstruction de l'environnement urbain à partir d'images. Les entrées typiques de notre travail est un ensemble d'images de façades, des empreintes au sol de bâtiments, et des modèles 3D reconstruits à partir d'images aériennes. Les principales étapes comprennent le calibrage des images,le recalage avec le modèle 3D, la récupération des informations de profondeur ainsi que la sémantique des façades.Pour atteindre cet objectif, nous utilisons des techniques du domaine de vision par ordinateur, reconnaissance de formes et de l'informatique graphique. Les contributions de notre approche sont présentés en deux parties.Dans la première partie, nous nous sommes concentrés sur des techniques de reconstruction multi-vues dans le but de récupérer automatiquement les informations de profondeur de façades à partir un ensemble des photographies non calibrées. Tout d'abord, nous utilisons la technique structure et mouvement pour calibrer automatiquement l'ensemble des photographies. Ensuite, nous proposons des techniques pour le recalage de la reconstruction avec un modèle 3D. Enfin, nous proposons des techniques de reconstruction 3d dense (stéréo multi-vues et voxel coloring) pour produire un maillage 3D texturé d'une scène d'un ensemble d'images calibrées.La deuxième partie est consacrée à la reconstruction à partir d'une seule vue et son objectif est de récupérer la structure sémantique d'une façade d'une image ortho-rectifiée. La nouveauté de cette approche est l'utilisation d'une grammaire stochastique décrivant un style architectural comme modèle pour la reconstruction de façades. nous combinons un ensemble de détecteurs image avec une méthode d'optimisation globale stochastique en utilisant l'algorithme Metropolis-Hastings. / The main goal of this thesis is to develop innovative and practicaltools for the reconstruction of buildings from images. The typical input to our workis a set of facade images, building footprints, and coarse 3d models reconstructedfrom aerial images. The main steps include the calibration of the photographs,the registration with the coarse 3d model, the recovery of depth and sematicinformation, and the refinement of the coarse 3d model.To achieve this goal, we use computer vision, pattern recognition and computergraphics techniques. Contributions in this approach are presented on two parts.In the first part, we focused on multiple view reconstruction techniques withthe aim to automatically recover the depth information of facades from a setof uncalibrated photographs. First, we use structure from motion techniques toautomatically calibrate the set of photographs. Then, we propose techniques for theregistration of the sparse reconstruction to a coarse 3d model. Finally, we proposean accelerated multi-view stereo and voxel coloring framework using graphicshardware to produce a textured 3d mesh of a scene from a set of calibrated images.The second part is dedicated to single view reconstruction and its aim is to recoverthe semantic structure of a facade from an ortho-rectified image. The novelty ofthis approach is the use of a stochastic grammar describing an architectural style asa model for facade reconstruction. we combine bottom-up detection with top-downproposals to optimize the facade structure using the Metropolis-Hastings algorithm.
6

Part Embedding For Shape Grammars

Yalim Keles, Hacer 01 July 2010 (has links) (PDF)
Computational modeling of part relations of shapes is a challenging problem that has been addressed by many researchers since sixties. The most important source of the difficulty is the continuous nature of shapes, which makes the expression of shape very difficult in terms of discrete parts. When discrete parts are combined, they fuse and yield new parts, i.e. parts emerge. There is a number of methods that support emergent part detection. However all of these methods are based on strong assumptions in terms of what constitute a part. There is a need for a generic solution that treats a shape independently of any restriction resulting from analytical, geometrical, or logical abstractions. To this end, we have developed two novel strategies, which can be used both separately and jointly. Both strategies are relatable to the algebraic formalization of shape grammars (by Stiny). In the course of this thesis work, we have introduced a novel data structure called Over-Complete Graph to address the problem of part embedding in the existence of discrete registration marks / and we have developed a novel and robust method for the automatic selection of registration marks. Both developments are certainly useful for other visual problems. On the application side, we have tested our techniques on puzzling Seljuk patterns (from Kayseri) to demonstrate how the developed techniques give way to computational creativity. Apart from the techniques we have developed, the most important contribution of our work is that shapes are treated as perceived wholes rather than composed, as compellingly demonstrated by Seljuk pattern experiments.
7

Rethinking The Architectural Design Process Through Its Computable Body Of Knowledge

Ergun, Eser 01 June 2008 (has links) (PDF)
This thesis assumes the architectural design process as a systematic study, in which knowledge is stored, organized and operated on by computational methods. From this perspective, the study explores the efforts for systemizing the architectural design process. Firstly, the focus is on the early approaches of systemizing design in the Design Methods Movement. The thesis identifies and evaluates the use of a number of critical concepts in this movement and in recent architecture practice, in order to see the development and transformation of design methods in terms of computing knowledge in a systematic way. The thesis evaluates the features that make design systematic within the Design Methods Movement and inquires whether such features like complexity, hierarchy, feedback loops and selection are influential in recent computational design methods of architecture. The thesis looks into two generative design methods, namely evolutionary design and shape grammars, which have been studied by designers since the 1960s, the start of the Design Methods Movement. These two methods exemplify current systematic approaches to design and according to the thesis these are the instances of how recent architecture employs the features discussed as characteristic in the Design Methods Movement.
8

Towards of a theory of reconstructing ancient libraries

Mamoli, Myrsini 22 May 2014 (has links)
The library was one of the most important institutions in the Hellenistic and Roman city, as evidenced in the writings of ancient authors, and the building remains of libraries found throughout the Greco-Roman world, from Asia Minor to France and from Africa to Northern Greece. Yet, the library remains one of the least easily identifiable building forms and one of the most difficult to reconstruct, because unlike architectural types such as the temple, stoa, or theater, the library exhibits significant variety in design, scale and monumentality and the use of different component elements. In reconstructing libraries, scholars often rely on a prescribed set of assumptions about components and their arrangement that limit our ability to identify libraries and understand their diversity of arrangement. This dissertation proposes shape grammars as an effective computational methodology to identify, understand, and reconstruct ancient libraries of diverse and variant scale, design and monumentality. The work presents a comprehensive documentation of known and identified libraries, reviews the design principles of the architectural form of ancient libraries, and on the basis of this historical analysis proposes a shape grammar for the formal specification of ancient Greek and Roman libraries. The library grammar encodes the design principles of ancient libraries in ninety-one rules that are grouped in two major parts: the first generates the main hall of the library and its interior design, and the second generates the complete layout of the library including additional porticoes, peristyles, exedras, gardens and propylon. The application of the rules generates libraries of diverse scales and monumentality: libraries known in the corpus and as well as hypothetical libraries. The dissertation presents grammatical derivations for the seventeen known and identified libraries. These derivations, depending on the degree of preservation of the building remains of libraries, function as an evaluative tool for the validity of the grammar or for the reconstructions proposed by traditional research. In many cases, they point to different possibilities in the identification of the building remains related to libraries among remains of different phases or remains belonging to neighboring buildings, and suggest variant scenarios of reconstruction that might not stand out using traditional techniques of reconstruction. The metadata of the rules in the grammar and the derivations are used in a frequency analysis that provides a probabilistic model as an effective and systematic guide in identifying, evaluating and predicting the architectural form of libraries: the main hall and the threshold are identified as mandatory architectural components, the niches and focal point as most likely, and the podium with a colonnade as less likely to occur in a library. Less frequently, the library is a whole complex with exedras, a monumental entry and additional rooms that function as auditoria, banquet halls or offices. Moreover, the work presents the derivations of possible libraries and evaluates the rules applied to generate them based on the frequency analysis. In the end, the work concludes whether these buildings are libraries, non-libraries or exceptional libraries. Lastly, this dissertation assesses the opportunities and challenges that emerge in using shape grammars to identify and reconstruct libraries and also the value and impact of using formal computational methods in the systematic exploration of variations in reconstruction of the archaeological record.
9

Procedural reconstruction of buildings : towards large scale automatic 3D modeling of urban environments / Reconstruction procédurale de bâtiments : vers l’automatisation à grande échelle de la modélisation 3D d’environnements urbains

Simon, Loïc 25 July 2011 (has links)
La présente thèse est consacrée à la modélisation 2D et 3D d’environnements urbains à l’aide de représentations structurées et de grammaires de formes. Notre approche consiste à introduire une représentation sémantique de bâtiments, qui encode les contraintes architecturales attendues, et qui soit capable de traiter des exemples complexes en utilisant des grammaires très simples. En outre, nous proposons deux nouveaux algorithmes d’inférence permettant l’analyse grammaticale d’images en utilisant ces grammaires. En premier lieu, un algorithme dit de hill climbing permet d’extraire les règles de grammaire et les paramètres correspondants à partir d’une vue unique d’une façade. Ce concept combine astucieusement les contraintes grammaticales et les propriétés visuelles attendues pour les différents éléments architecturaux. Cependant, afin de pouvoir traiter de cas plus complexes et également d’incorporer de l’information 3D, une deuxième stratégie d’inférence basée sur des algorithmes évolutionnaires a été adoptée pour optimiser un fonction à deux objectifs qui introduit notamment des notions de profondeur. Le système proposé a été évalué tant qualitativement que quantitativement sur un panel de façades de référence toute munies d’annotations, démontrant ainsi sa robustesse face à des situations d’abords difficiles. Grâce à la force du contexte grammatical, des améliorations substantielles ont été démontrées par rapport aux performances des mêmes modèles couplés à des a priori uniquement locaux. Par conséquent, notre approche fournit des outils puissants permettant de faire face à la demande croissante en modélisation 3D d’environnements réels à large échelle, grâce à des représentations sémantiques compactes et structurées. Ce travail ouvre par ailleurs un vaste champ de perspectives pour le domaine de l’interprétation d’images / This thesis is devoted to 2D and 3D modeling of urban environments using structured representations and grammars. Our approach introduces a semantic representation for buildings that encodes expected architectural constraints and is able to derive complex instances using fairly simple grammars. Furthermore, we propose two novel inference algorithms to parse images using such grammars. To this end, a steepest ascent hill climbing concept is considered to derive the grammar and the corresponding parameters from a single facade view. It combines the grammar constraints with the expected visual properties of the different architectural elements. Towards addressing more complex scenarios and incorporating 3D information, a second inference strategy based on evolutionary computational algorithms is adopted to optimize a two-component objective function introducing depth cues. The proposed framework was evaluated qualitatively and quantitatively on a benchmark of annotated facades, demonstrating robustness to challenging situations. Substantial improvement due to the strong grammatical context was shown in comparison to the performance of the same appearance models coupled with local priors. Therefore, our approach provides powerful techniques in response to increasing demand on large scale 3D modeling of real environments through compact, structured and semantic representations, while opening new perspectives for image understanding
10

A gramática da habitação mínima : análise do projeto arquitetônico da habitação de interesse social em Porto Alegre e Região Metropolitana

Mayer, Rosirene January 2012 (has links)
A presente tese propõe um modelo geométrico paramétrico para a geração, baseada em regras, da geometria do projetos de Habitação de Interesse Social, HIS, adequada à realidade socioeconômica brasileira. A definição do modelo partiu da análise dos padrões existentes na morfologia dos projetos arquitetônicos de uma amostra da produção de HIS de Porto Alegre (Rio Grande do Sul, Brasil) e Região Metropolitana. A identificação destes padrões serviu para acessar os limites de variação e qualificação do projeto da HIS. Foram utilizadas representações adimensionais associadas a grafos de adjacência para descrição das relações espaciais mais freqüentes em dois níveis distintos porém relacionados - para o equipamento e para os compartimentos. O modelo de Gramáticas da Forma serviu à descrição das regras de composição e configuração do espaço e seus componentes. A análise comparativa do corpus e das necessidades programáticas forneceu a variação admissível dos parâmetros dimensionais. A implementação computacional do modelo geométrico resultante permitiu a exploração das variações paramétricas das alternativas de configuração de projeto. Os resultados permitiram verificar uma homogeneidade da estrutura sintática do corpus que ultrapassa os limites tipológicos. Parte das diferenças existentes entre os elementos da amostra podem ser atribuídas a variações paramétricas das partes e a sua influência mútua na composição da área total e da forma da unidade habitacional. Variações paramétricas de uma configuração podem servir para adaptar a inserção da unidade habitacional no lote ou no edifício. A aplicabilidade do modelo geométrico paramétrico pode ser vista sob dois aspectos interrelacionados: como matriz generativa para o desenvolvimento de projetos mais adequados a problemas específicos e, conseqüentemente, e como uma alternativa a padronização da produção habitacional. / This thesis proposes a parametric geometrical model for the rule-based generation of the configurational geometry of social housing architectural designs, suitable to the Brazilian socioeconomic context. The model was based on analysis of existing patterns identified in the morphology of architectural designs from a sample of the social housing production in Porto Alegre and Metropolitan Area. The identification of these patterns was intended to access the limits of variation and qualification of social housing designs. The association between dimensionless representations and adjacency graphs was used for the description of spatial relations in two distinguished but related levels: for the furniture and the rooms. The shape grammars model was used to describe the geometrical rules governing the composition and configuration of the space and its components. The comparative analysis of the corpus and functional needs enabled to identify the admissible variation of the dimensional parameters. The computational implementation of the resulting geometrical model allowed the exploration of the parametric variations in the design configuration alternatives. The results showed homogeneity of syntactic structure of the corpus, which overcomes the typological limits.! Part of the differences between the elements of the sample may be attributed to the parametric variations in rooms and their mutual influence on the composition of the total area and the shape of the housing unit. The parametric variations in a design can also enable setting the location of the housing unit on a plot or in a building. The application of the parametric geometrical model can be seen in two interrelated aspects: as a generative matrix for the development of projects best suited to specific problems, and consequently, as an alternative to the standardization of housing production.

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