3D urban models

The paper is a follow-up to earlier work investigating the research hypothesis that Virtual Reality (VR) is nowadays a maturetechnology, suitable for communicating planning ideas. A work in progress involving the redesign of two squares within the urbanfabric of a deprived Athenian neighbourhood is presented. A VR model of existing and proposed layouts was constructed, focusingon accuracy of visualisation, ease of navigation, online spatialized commenting mechanism and ease of access. User groups weresupported with appropriate training?researchers had the opportunity to observe the reactions of people and deliver questionnairesthat help identify problem areas related to technophobia, disbelief, past knowledge, communication skills, understanding of thevisualisation system used, usability of the navigation system as well as the commenting mechanism. Gender and social exclusionare key issues in this particular multicultural neighbourhood. Collecting demographic data on all participant...

Digital twins are enjoying widespread and growing success in both theoretical and practical applications. A recent development that is gaining increasing traction is the application of digital twins to cities. The aim of this article is to discuss whether there are inherent limitations in this case. At present, the scientific literature on urban digital twins is dominated by "technical" approaches. Critical investigation of digital twins-especially from a philosophical perspective-is still at its beginnings. This article aims to contribute to this line of inquiry. It is mainly theoretical and analytical. On the basis of a specific conceptual framework, it examines digital twins and their applications in urban contexts. It starts by distinguishing among simple, complicated and complex systems, and reaches the conclusion that, while using digital twins is generally appropriate (and often helpful) in the first two of these systems, there are some structural limitations on their use in the case of complex systems. In the latter case, inherent limitations depend on certain distinctive aspects of complex systems, such as their emergent and unpredictable nature, and the role played in this regard by "dispersed knowledge" (that is, is a form of diffused practical knowledge that is crucial for the functioning of large urban systems but that cannot be collected and re-unified because, as a coherent and integrated whole, it does not and cannot exist anywhere).

The assessment of the solar potential in urban areas relies on a geometrical model that can be defined at different levels of detail (LOD). In this work we compare the solar irradiation simulated on the surfaces of four sample buildings, which were modeled at three different LODs as defined by the CityGML standard. Results indicate a general overestimation of the solar irradiation when using LOD1 and LOD2 models, if we consider LOD3 (i.e. the finer model) as the ground truth. However, results show also that the error varies significantly between the analyzed buildings and the considered minimum irradiation thresholds and, if we take into account only rooftops, the effect of added elements might result either in an overestimation or an underestimation of the annual total irradiation. We conclude by discussing how such findings should influence current practices in the assessment of the solar potential at the urban scale.

The assessment of the solar potential in urban areas relies on a geometrical model that can be defined at different levels of detail (LOD). In this work we compare the solar irradiation simulated on the surfaces of four sample buildings, which were modeled at three different LODs as defined by the CityGML standard. Results indicate a general overestimation of the solar irradiation when using LOD1 and LOD2 models, if we consider LOD3 (i.e. the finer model) as the ground truth. However, results show also that the error varies significantly between the analyzed buildings and the considered minimum irradiation thresholds and, if we take into account only rooftops, the effect of added elements might result either in an overestimation or an underestimation of the annual total irradiation. We conclude by discussing how such findings should influence current practices in the assessment of the solar potential at the urban scale.

The assessment of the solar potential in urban areas relies on a geometrical model that can be defined at different levels of detail (LOD). In this work we compare the solar irradiation simulated on the surfaces of four sample buildings, which were modeled at three different LODs as defined by the CityGML standard. Results indicate a general overestimation of the solar irradiation when using LOD1 and LOD2 models, if we consider LOD3 (i.e. the finer model) as the ground truth. However, results show also that the error varies significantly between the analyzed buildings and the considered minimum irradiation thresholds and, if we take into account only rooftops, the effect of added elements might result either in an overestimation or an underestimation of the annual total irradiation. We conclude by discussing how such findings should influence current practices in the assessment of the solar potential at the urban scale.

In the 3D-modelling universe, the Level of Detail has a crucial role, as it is the case to assess the PV potential in urban environments using this kind of models. According to the CityGML standards, there are five levels of detail, going from the footprint (LOD0) to a precise model with inside and outside details (LOD4) as stairs and chimneys. For the subject we are studying, meaning the assessment of the PV potential, the inside details are totally superfluous. That is why we are going to consider the LOD3 model as a perfect model. But an LOD3 model costs a lot more to do than an LOD1 or LOD2. This brings us to the main question we will try to answer in this paper: Is it useful to do an LOD3 model, or are LOD1 and LOD2 models precise enough to assess the PV potential of a building, or even of a city? The second part of the paper will handle the theme of the shading effects. Indeed, the production of electricity of PV cells is affected when a part of the cell is shaded. Therefore, ...

Urban skylines have a dynamic structure because they reflect changing conditions in time and space. This dynamic structure also has the potential to be an urban information tool for evaluating the visual qualities  and complexities of cities. This article presents a new methodological perspective on urban skyline studies through fractal analysis in Istanbul. In the last 30 years, several computational techniques have been developed to measure the morphological characteristics of cities. Fractal analysis, the most well-known and widespread of these, is used in this study to analyze the complex structure of urban skylines obtained through visual data. The study aims to first expose the existing urban skyline of Istanbul and then assess the influence of the factors influencing this skyline on its appearance by using fractal geometry. The fractal dimension, measured by the box count is used for this purpose and that is a metric used to describe the complexity of urban skylines. In this study, in which Beyazıt Fire Tower is accepted as the reference point, the fractal dimensions of the skyline obtained from urban panoramas are calculated using the ImageJ Program and FracLac plugin. As a result of the fractal analysis of the skyline, fractal dimensions in the range of 1,0731-1,2171 were obtained. The skylines and their trends are presented through the rose diagram, and fractal analysis shows that two main elements complicate the appearance of the city the most which are: mosque and skyscrapers

City image includes people's perceptions of the built and natural environments as well as the emotions and ideas the city arouses in them. In the city image, the preservation of the buildings, especially historical buildings, which carry the past cultures, meaning and structural features of the city to the present day, can be ensured by making these buildings visible and perceptible by the inhabitants. Historical buildings' visibility can facilitate the recognition and appreciation of their historical significance, thereby contributing to the preservation of the city's cultural heritage. This study aims to analyse the visibility of a historical building that holds a significant place in the urban memory and to suggest recommendations for enhancing its visibility. In this context, the viewpoints used to examine the İskenderun Beş Temmuz Primary School Historical Building's visibility were specified by space syntax visibility graph analysis (VGA). Subsequently, the building's visibility in three different historical periods was determined by the isovists technique, utilizing these viewpoints. Based on the same viewpoints, an observational field study and a survey applied to 47 people were conducted. Consequently, it was identified that the historical building could not be sufficiently seen due to the presence of surrounding service structures, perimeter walls, and high buildings. Furthermore, this study proposed the removal of additional structures that negatively affect historical building's visibility. Additionally, a design approach was developed for new buildings and landscaping to enhance the historical building's visibility, and the efficacy of the proposed design was evaluated through isovists and VGA analyses.

City image includes people's perceptions of the built and natural environments as well as the emotions and ideas the city arouses in them. In the city image, the preservation of the buildings, especially historical buildings, which carry the past cultures, meaning and structural features of the city to the present day, can be ensured by making these buildings visible and perceptible by the inhabitants. Historical buildings' visibility can facilitate the recognition and appreciation of their historical significance, thereby contributing to the preservation of the city's cultural heritage. This study aims to analyse the visibility of a historical building that holds a significant place in the urban memory and to suggest recommendations for enhancing its visibility. In this context, the viewpoints used to examine the İskenderun Beş Temmuz Primary School Historical Building's visibility were specified by space syntax visibility graph analysis (VGA). Subsequently, the building's visibility in three different historical periods was determined by the isovists technique, utilizing these viewpoints. Based on the same viewpoints, an observational field study and a survey applied to 47 people were conducted. Consequently, it was identified that the historical building could not be sufficiently seen due to the presence of surrounding service structures, perimeter walls, and high buildings. Furthermore, this study proposed the removal of additional structures that negatively affect historical building's visibility. Additionally, a design approach was developed for new buildings and landscaping to enhance the historical building's visibility, and the efficacy of the proposed design was evaluated through isovists and VGA analyses.

The architectural design process is an intricate dance between imagination and technical execution. While initial ideas often blossom on a napkin or sketchbook, translating those sketches into polished renderings for client presentations can be a time-consuming bottleneck. PromeAI's "Sketch Rendering" feature is poised to disrupt this traditional workflow, empowering architects with an AI-powered tool that breathes life into their early design concepts.

The study investigates the effect of the environment on the perception of tall buildings with the fractal analysis method. According to the hypothesis, tall buildings are appreciated to the extent that their fractal dimension value (fdv) matches the fdv of the urban environment. If the fdv of the buildings is higher than the environment, complexity and impression increase, and liking decreases. Suppose the fdv of the buildings are lower than the environment; complexity, impression, and liking decrease. In the first stage, 24 tall building models with the same height (200 meters) were designed in the Sketchup program according to the variables of forms (8) and facades (3). These models were added in two different environments. Both environments are located on Atatürk Boulevard, the main artery of Ankara city, Turkey. The fractal similarity ratios of the models were measured with ImageJ and its plug-in Fraclac. In the second stage, the reliability of the data was questioned with a questionnaire. The survey was conducted with senior students of Gazi University, Department of Architecture. The students were shown 48 images of the models and asked to evaluate these images according to liking, impression, and complexity variables. The study found that images with a high fractal similarity ratio were the most liked. When fdv was higher than the environment, complexity and impression increased, and liking decreased. On the contrary, complexity, impression, and liking decreased. As a result, it was found that there was a significant relationship between fdv and the perception and appreciation of tall buildings.

In this paper, we suggest a generic city description model suited for purposes like semi-automatic city modeling and urban layout evaluation. The generic city model refers to basic vital functions of a (computable) city. Feature patterns are used to extend the generic city model with global and local characteristics. The Hellenistic cities serve as a platform for a first implementation to test a semi-automatic city model generation. As a result four cities are reconstructed as a first example of our ongoing work, Miletus, Knidos, Priene and Olynthus. Future work will deal with the application of the generic city model to the performance simulation of contemporary urban layouts.

Procedural Parcel Generation. Our method creates parcels inside city blocks (f,i) using two different subdivision techniques-skeleton (g, shaded part of f) or OBB (h, unshaded part of f). The subdivision attributes are automatically extracted from observed real-world cities (a,b,c) or determined by the user. The resulting parcel configurations closely resemble real-world subdivisions, as shown by our statistical and visual comparison of procedural and observed parcel datasets (d,e).

Visibility is a significant parameter for defining, developing, and evaluating space in the AEC (Architecture, Engineering, and Construction) Industry. Therefore, visibility is considered when designing visually comfortable buildings. Visibility is also a significant parameter in building appraisal. Therefore, in this study, visibility was examined through 3-dimensional (3D) isovists, which are thought to represent the human perception of vision. Visibility was examined regarding spatial openness and mathematically calculated "visual openness indexes" were developed for building valuation. The analysis area was selected in Istanbul, and the urban model was created by using Geographic Information System (GIS) data in Building Information Modelling (BIM) software. Due to, economic reasons affecting different stakeholders in building valuation, it is necessary to create an accurate urban model. For this reason, in the study, the process of obtaining current and accurate GIS data covering the world from open sources is preferred. Then, the process of correctly transferring GIS data to BIM is explained. A sufficient urban model for analysis is created. To calculate the openness indexes, the dormitory in the Golden Horn was modelled in BIM, and different rooms' openness indexes were calculated. Some solutions have been presented to ensure the modelling process with large file sizes and in the calculation of visibility factors. To allow different AEC stakeholders to calculate these indexes, modelling, and calculation is done within BIM. Eventually, it was calculated how much the building users cognitively perceive the openness of the view, and a mathematical comparison of the different rooms' openness indexes was provided.

One of the fundamental indicators for evaluating visual continuity in the preservation of historical landscapes is the visual experience gained through sequential views in urban space. Controlling the valuable visual qualities is essential to maintain the precious sequential view of the historical landscape. The visual perspective of pedestrians and the wayfinding roles of urban landmarks are central issues in the visual experience of historical cities. The evaluation of visibility analysis is performed using the scene-capturing method via photographic survey. This method is combined with 2D isovist and 3D viewshed analysis as a computational approach applied to five historical landmarks in Malang, Indonesia. The scene-capturing methodology examines the sequential view series of each landmark from various approaching paths by extracting the landmark's silhouette and segmenting the visibly distinct areas of the scene. Subsequently, 2D isovist and 3D viewshed analyses investigate the pattern of the visual field spectrum along each route. As a result, the best visibility rate at the closest observation distance is achieved by the Frateran School Building at 9.58%, while the best visibility at the farthest observation distance is observed at the Kayutangan Church Building at 0.97%. The range of observation distances with a significant percentage of visual sightings is from 75m-100m, with the closest observation distance ranging from 50-75 meters. Combining sequential photo mapping and isovist analysis provides a powerful tool for managing and enhancing the visual experience, which can inform decisions on urban planning, architectural design, and historical preservation.

The current volume is the product of an international meeting entitled "Spatial analysis in past built environments" which took place in the framework of the Excellence Cluster "Topoi: The formation and transformation of space and knowledge in ancient civilizations". Topoi is an interdisciplinary research network which is concerned with the study of the ancient world. It was launched in 2008 and is mainly represented by two universities and four research institutions based in Berlin: the Free University, the Humboldt University, the Berlin-Brandenburg Academy of Sciences and Humanities (BBAW), the Deutsches Archäologisches Institut (DAI), the Max Planck Institute (MPI) for the History of Science, and the Stiftung Preußischer Kulturbesitz (SPK). The cluster is part of the Excellence Initiative of the German federal and state government and involves the participation of more than 200 researchers from diverse disciplines, such as archaeology, geography, history, cultural studies, linguistics, philology, philosophy, theology, and history of science. To date, the network consists of about 50 research groups that investigate the interdependence of space and knowledge in the civilisations of the Mediterranean, the Ancient Near East, Black Sea and Eurasian steppe regions from the 6th millennium BC to around 500 AD. This research programme acknowledges and explores the important role of spaces, spatial systems and various types of space-related knowledge in the development of ancient cultures. Since 2008 the Topoi Excellence Cluster has funded and organised at least one international conference or workshop each month, and has published selected contributions presented at these meetings in the "Topoi. Berlin Studies of the Ancient World" series. This series has proven extremely useful for compiling an up-to-date overview of the scientific results of the cluster, and reflects the breadth and multidisciplinary focus of research in Topoi. The present volume is also part of this publication scheme and is expected to contribute conceptually and methodologically to key research areas in the Topoi Excellence Cluster.

Small apartments exist in dense cities worldwide. Developing adequate quality small apartments in city centres would strongly attract current demand. Analysis, predictive tools and design concepts regulated for better interior design and lower perceived density would provide residential environments with happier tenants. This research evaluates perceived density and visual privacy in alternative minimum apartments based on the spatial openness index threedimensional visibility analysis, i.e. their accumulated three-dimensional visibility calculations. The compatibility of the spatial openness index concept as predicting perceived density in minimum apartments was examined and assessed. An empirical study was conducted using a virtual reality experiment in a controlled environment-An immersive three-dimensional visualisation laboratory 1 , with more than 100 subjects participated in the experiment. Significant relations were found between perceived density and visual privacy for all apartments (single and double story). The measured volume of visible space from the door viewpoint (the entrance to minimum apartments) and the perceived density evaluated there by participants, and a general evaluation for the apartment are strongly related for both (single and double story groups). Strong correlation was found between visibility measurements from the door and the 'visual privacy' at the sofa/bed. According to assessment results the spatial openness index three-dimensional visibility analysis can predict the perceived density of minimum apartments.

In the last twenty years, computer tools have progressively enabled the modeling of buildings and cities in lesser time and cost, along with an increase in the results quality. A city modeled according to planning regulations usually present a correlation between plots and buildings dimensions. The representation of such correlation for a large number of plots requires repetitive work, thus suggesting the use of a computational tool to perform the task. Existing CAD, GIS, and VR software can generate accurate representations of the reality, but have no capabilities to simulate the impact of alternative urban regulations for large number of plots in a short period of time. CityZoom is a Decision Support System for urban planning, with a specific builtin city model, where data is represented in an object-oriented model representing the urban structure. CityZoom not only provide CAD tools, but a shell where different performance models can operate iteratively. It can simulate given urban regulations applied to a set of urban plots, as well as address environmental comfort issues such as shadow casting between buildings. Results can be displayed as tables, graphs, and in a 3D preview of the whole city or part of it. It's also possible to export them to commercial GIS tools, to perform different data analysis. The graphical outputs make for an easy understanding of the results by laymen, an important feature for participatory planning, while the display of the correspondent numerical data enable correlations with indicators and parameters of urban quality.

Excavations at Akrotiri in the years 1999-2002 yielded new evidence on the history of habitation at the site from the Neolithic period to the LC I/LM IA final phase of the settlement and uncovered new sectors of the LC I town at the north part of the as yet excavated area. This paper presents evidence from this newly-excavated north sector, with emphasis on the nature of the domestic units uncovered in the north/northwest part and the activities of the inhabitants during the disruptive phase before the volcanic eruption.

The expansion of the LC I settlement to the north was apparently a communal decision implemented during the reorganisation of the layout of the town at the end of the MC period. The limited evidence for earlier remains in the area and the configuration of the new sector by the same principles of urban planning evident in other parts of the settlement (with provision for roads, squares, sewage system) demonstrate that the transformation of the physical landscape in response to particular needs complied with rules set on the community level. Of particular interest is the comparison of the newly-uncovered two-storied domestic units with other buildings and complexes in the settlement, in terms of function and interdependence. Moreover, the ample evidence for systematic and well-planned re-organisation activities attested in the settlement as a result of collective action in the period just before the eruption, further substantiates the argument for a high level of social integration in the community. In light of the absence, as yet, of any building that could qualify as the administrative seat of a ruler or a body of rulers at Akrotiri, the discussion on the role of Houses in the political and economic organisation of the community certainly affords due consideration.

Continuing pressure on urban areas due to growing population and further urbanization affects urban quality. Many cities and agglomerations try to cope with negative effects of urban sprawl by further densification of existing built-up areas. As a consequence green and open spaces are disappearing. Among other ecological and socioeconomic urban qualities, this is affecting the sense of a place and place attachment of the local inhabitants. However, there are no indicators available, which allow in planning processes for an effective assessment of the impact of further densification on the urban landscape's identity. One challenge is that assessing the impact on the landscape's identity requires both objective and subjective approaches. Objective approaches are well established, for example, in environmental impact assessments untypical elements of a landscape contributing to a loss in landscape aesthetics and character are evaluated. However, these approaches are rather applicable on the rural than on the urban landscape. Furthermore, subjective approaches still lack of suitable tools for integrating individual perceptions of stakeholders into the evaluation process. In this paper we present an approach based on GIS-and rule-based interactive modeling and visualization tools, which allows for objective and subjective assessment of the urban landscape's identity in participatory planning processes. For the case study of Schlieren, an agglomeration of the city of Zurich (CH), we show exemplarily the implementation of this approach. Combined assessment of hard and soft factors of urban green and open spaces contributing to the urban landscape's identity provides a powerful tool to identify local thresholds of urban densification, and thus proactive planning of sustainable urban development taking into account the residents' requirements directly.

This paper responds to a gap observed between the contemporary capacity for calculation and analysis of visibility of built environment features, such as buildings, in digital urban and architectural computational research models and the functionality of off-the-shelf software tools available to professionals. The research investigates the potential of visibility analysis to be embedded and extended within computational-based workflows of software tools to better meet urban design and planning industry needs. We introduce a novel method for visibility calculation that exposes output data for further analysis within a computational workflow and implement it in a game development engine used by software tool providers. Based in our engagement with a local government authority, we then use that method to demonstrate a workflow in the context of form-based building codes in which the visual impact of a building is considered rather than prescriptive limits on dimensions and use. Our results indicate the novel method has substantial performance improvements compared to an alternative mode of visibility calculation and that software providers could more thoroughly integrate and extend visibility analysis to meet industry needs.

Parametric urban design is a potentially powerful tool for collaborative urban design processes. Rather than making oneoff designs which need to be redesigned from the ground up in case of changes, parametric design tools make it possible keep the design open while at the same time allowing for a level of detailing which is high enough to facilitate an understanding of the generic qualities of proposed designs. Starting from a brief overview of parametric design, this paper presents initial findings from the development of a parametric urban design tool with regard to developing a structural logic which is flexible and expandable. It then moves on to outline and discuss further development work. Finally, it offers a brief reflection on the potentials and shortcomings of the software ‐ CityEngine ‐ which is used for developing the parametric urban design tool.

Urban spaces consist of a complex collection of buildings, parcels, blocks and neighbourhoods interconnected by streets. Accurately modelling both the appearance and the behaviour of dense urban spaces is a significant challenge. The recent surge in urban data and its availability via the Internet has fomented a significant amount of research in computer graphics and in a number of applications in urban planning, emergency management and visualization. In this paper, we seek to provide an overview of methods spanning computer graphics and related fields involved in this goal. Our paper reports the most prominent methods in urban modelling and rendering, urban visualization and urban simulation models. A reader will be well versed in the key problems and current solution methods.

The use of rule-based modelling and historical data for scenarios to improve resilience within the building stock Digital documentation has become integral to the preservation, analysis and communication of historical sites. New platforms are now being developed that involve complex 3D models and allow the analysis of spatial data. These include procedural modelling, a technique that enables the rapid development of 'dynamic' 3D environments, and generation of simulations for entire cities, resulting in low cost, high resolution 3D city models. Though procedural modelling has been used in the context of archaeology to 'recreate' cities at specific historic time points, the use of historical data in the development of rule-based procedural models for current cities has been little explored. Here, we test the extent to which construction age data, historical building regulations and architectural knowledge can be used in the generation of procedural rules, and the level of detail and potential impact that these models may have. Rather than creating an accurate representation of the city, we instead seek to simulate the way in which urban areas are likely to behave under certain conditions, in order to test what-if? planning scenarios. This allows us to explore more flexible ways of digitally 'creating' cities, past and present, and to gain insights into underlying 'rules' that govern their physical form.

The use of rule-based modelling and historical data for scenarios to improve resilience within the building stock Digital documentation has become integral to the preservation, analysis and communication of historical sites. New platforms are now being developed that involve complex 3D models and allow the analysis of spatial data. These include procedural modelling, a technique that enables the rapid development of 'dynamic' 3D environments, and generation of simulations for entire cities, resulting in low cost, high resolution 3D city models. Though procedural modelling has been used in the context of archaeology to 'recreate' cities at specific historic time points, the use of historical data in the development of rule-based procedural models for current cities has been little explored. Here, we test the extent to which construction age data, historical building regulations and architectural knowledge can be used in the generation of procedural rules, and the level of detail and potential impact that these models may have. Rather than creating an accurate representation of the city, we instead seek to simulate the way in which urban areas are likely to behave under certain conditions, in order to test what-if? planning scenarios. This allows us to explore more flexible ways of digitally 'creating' cities, past and present, and to gain insights into underlying 'rules' that govern their physical form.

This paper focuses on the definition of a conceptual participatory design framework for urban planning. Traditional planning methods can no longer satisfy the growing demands on sustainable urban planning in regard to factors such as complexity, problem size, and level of detail and these limitations make the development of new approaches necessary. Expert knowledge as well as insights from stakeholders and community members needs to take part equally in the decision-making process since they are responsible for a broad understanding and acceptance of final planning decisions. Therefore, a participatory framework is presented in the following, which integrates needs and requirements of stakeholders. In order to enable diverse groups of stakeholders to act conjointly, we propose the application of interactive decision support tools, which will leverage general conclusions especially to solve crucial zplanning decisions.

Abstract. We propose a three-step participatory design cycle for the early urban design phase that can be integrated into the digital design chain. Step one involves a visualization method that is implemented as an interactive card-based interview technique for the collaborative ...

In the past decade a certain number of studies have suggested that shape grammars and their capability for producing alternative solutions represent an adequate tool for overcoming complexities regarding urban design. In this paper we present a critical analysis of various approaches to shape grammar application in urban design. The aim of this research is to provide an insight into the current state-of-the-art developments and give a critical evaluation on the basis of the criteria of interactivity and flexibility in the approach. We identify two main concepts of grammar application in urban design and outline their characteristics. We conclude that a generic or context-independent approach to shape grammars can provide high levels of flexibility and interaction with the user. This, coupled with their ability to encode different layers of information, facilitates their use for design exploration and problem solving in an urban context.

In the past decade, digital technologies had a great impact on contemporary architectural practice, design and theory. CAD/CAM technologies opened up new opportunities by allowing design and production of complex geometric shapes. One of the first applications of computational process in architecture was based on using shape grammars, a rule-based expert systems in artificial intelligence generating geometric shapes. Early applications of shape grammars in art and architecture started shortly after its invention during the 70ies and 80ies of the XX century, however, their potential as a generative design tool still has not been fully exploited in practice. Despite their popularity in academic circles, shape grammars have not found a widespread place/usage in computer aided architectural design. Role of shape grammar as a generative design and analysis tool and their influence on contemporary architectural design and theory are examined in this paper. Also, new and ongoing issues concerning shape grammars are discussed in order to indicate further directions of their usage.

This paper examines procedural modeling as a tool for 3D modeling creation. Procedural modeling historically has been used for 3D visualization of natural features, but with the release of the software CityEngine in 2008, the technology can easily be adopted also in problem domains dealing with urban environments.Then, we will examine and compare two types of modeling, traditional and procedural modeling and consider the advantages of procedural modeling. furthermore, reviewed the features of CityEngine software and introduced CityEngine as a software application that uses the procedural modeling system.Procedural modeling deals with (semi-)automatic content generation by means of a program or procedure. We survey procedural methods that are useful to design roads, buildings, and entire cities. In this survey, we focus particularly on the degree of the use of procedural modeling in the design of cities, streets, buildings, etc, in by CityEngine software. This paper examines how arch...

Climate-Based Daylight Modelling (CBDM) differs from other daylight simulation techniques in that it can produce representative results in physical and photometric units. The typical application of CBDM during the design of buildings or the planning of interventions however implies incomplete information, e.g. on the definitive furnishing, selection of surface properties, and installation of shades and glare controls. This is reflected by uncertainties and reduced level of detail (LoD) in the setup of models. Relying on a detailed model of an existing residential unit in Singapore, we assess the impact LoD by sequentially reducing model detail. Impact is assessed in terms of a) absolute quantities, e.g. illuminance, b) thresholded metrics, e.g. Daylight Autonomy and Daylight Glare Probability, and c) relative ranking based on these metrics. We demonstrate the implementation of the efficient zonal daylight simulation with Raytraverse and Radiance, and the processing of the spatio-temporal results with Python (and its numpy and scipy modules). An outlook into the possible extension of the study by accessing a building database is provided.

Urban areas are facing a growing deployment of solar technologies on the built exposed surfaces such as roofs and façades. This transformation often occurs without consideration of the needed architectural quality, which depends on the context sensitivity and on solar technologies visibility from public space. The definition of visibility is explored in this paper, and major assessment methods are described. Specifically, a Cumulative Viewshed Algorithm (CVS) is compared with a novel backward raytracing Illuminance Metric Approach (ILL). Results from a test-case in Geneva show how CVS better describes visibility from a remote perspective, while ILL is a promising and fast method for closer viewpoints, especially in urban canyon environments.

In recent years, the necessity of accurate 3D surface reconstruction has been more pronounced for a wide range of mapping, modelling, and monitoring applications. The 3D data for satisfying the needs of these applications can be collected using different digital imaging systems. Among them, photogrammetric systems have recently received considerable attention due to significant improvements in digital imaging sensors, emergence of new mapping platforms, and development of innovative data processing techniques. To date, a variety of techniques haven been proposed for 3D surface reconstruction using imagery collected by multi-platform photogrammetric systems. However, these approaches suffer from the lack of a well-established quality control procedure which evaluates the quality of reconstructed 3D surfaces independent of the utilized reconstruction technique. Hence, this paper aims to introduce a new quality assessment platform for the evaluation of the 3D surface reconstruction usi...

Articolo (ITA/ENG) in atti di convegno internazionale che tratta dei modelli tridimensionali reality based di comparti più o meno estesi di città, frutto di operazioni di rilevamento digitale integrato, i quali costituiscono ancora oggi lo ‘strumento’ più idoneo per analizzare i caratteri morfometrici dell’ambiente urbano e per suggerire, attraverso delle simulazioni ad hoc, le configurazioni future. Nel contributo viene enfatizzato il ruolo che tali copie digitali possono svolgere nei processi di urbanistica partecipata, consentendo di raffigurare e, pertanto, di veicolare con estrema chiarezza le criticità individuate e le soluzioni proposte, in una continua dialettica tra i diversi soggetti coinvolti. Nel testo viene fatto esplicito riferimento all’esperienza svolta all’interno del Programma Complesso di Riqualificazione Insediativa (PCRI) del comparto urbano tra Caletta di Castiglioncello e il canale del Lillatro a Rosignano Solvay (Rosignano M.mo), attraverso il quale un gruppo di ricerca dell’Università degli Studi di Firenze sta predisponendo una serie di interventi per migliorare la qualità dello spazio pubblico agendo sulle potenzialità inespresse dei manufatti e/o delle aree private.

Traditional urban plans have defi nitive design systems, without the fl exibility required to deal with the complexity and change that characterise contemporary urban societies. To provide urban plans with increased fl exibility, it is proposed a design methodology capable of producing various design solutions instead of a specifi c defi nitive design. The methodology uses shape grammars as a process for generating urban design. In this approach, design becomes a system of solutions rather than a specifi c one. Through the analyses of a group of urban plans, a design methodology was sketched in which rules are used to enable more fl exibility. These plans where chosen for their perceived qualities in terms of language, planning effi ciency, and latent fl exibility. As a result, a four-phased methodology was identifi ed and thus, proposed for designing urban plans. This methodology was then combined with shape grammars and tested in a design studio setting. Students were asked to use the methodology and shape grammars as auxiliary instruments in the design of a fl exible plan for a new town. In the following year, to simulate real-world conditions and oblige students to consider urban ordering and scale, work was structured differently. First, students were asked to develop a rule-based urban plan as in the previous year. Second, they were asked to conceive a detail plan for a sector of an urban plan defi ned by another group of students following its rules. The plans were then analysed with the goal of refi ning the methodology. Results show that shape grammars produce urban plans with non-defi nitive formal solutions, while keeping a consistent spatial language. They also provide plans with explicit and implicit fl exibility, thereby giving future designers a wider degree of freedom. Finally, they provide students with a concrete methodology for approaching urban design and foster the development of additional designing skills.

3D models of cities, visualised and exploded in 3D virtual environments have been available for several years. Currently a large number of impressive realistic 3D models have been regularly presented at scientific, professional and commercial events. One of the most promising developments is OGC standard CityGML. CityGML is object-oriented model that support 3D geometry and thematic semantics, attributes and relationships, and offers advanced options for realistic visualization. One of the very attractive characteristics of the model is the support of 5 levels of detail (LOD), starting from 2.5D less accurate model (LOD0) and ending with very detail indoor model (LOD4). Different local government offices and municipalities have different needs when utilizing the CityGML models, and the process of model generation depends on local and domain specific needs. Although the processes (i.e. the tasks and activities) for generating the models differs depending on its utilization purpose, there are also some common tasks (i.e. common denominator processes) in the model generation of City GML models. This paper focuses on defining the common tasks in generation of LOD (0-2) City GML models and representing them in a formal way with process modeling diagrams.

This course will explain procedural modeling techniques to create urban models for computer games and movies. It will quickly survey previously published techniques and theory, and then delve into their use in graphics practice: tool demonstrations, fitting to real and artistic data, the needs of gaming, and preparation for rendering. Creating digital content remains a significant challenge in the entertainment industry, especially for urban environments, which are among the largest and most complex. As display capabilities improve and audience expectations grow, procedural modeling techniques are becoming an increasingly important supplement to traditional modeling software. Attendees of this course will learn how techniques for generated urban models can be used in practice, and where these tools still fall short. In our first session, we will begin with a survey of existing tools, and new developments in the field. These include shape grammars, generative meshes, and procedural textures. Preparing models of this size and complexity for rendering remains a significant challenge. We will survey available techniques and options for rendering, including occlusion culling, imposters, and LOD, as well as how to prepare these urban models for rendering in Maya and Renderman. We continue with an in depth, interactive demonstration of the CityEngine, published previously in two SIGGRAPH papers. We will show how to use the CityEngine for both archeological and architectural applications. In our second session, we examine design of urban environments in the large. We examine real-life city form, and how planning attempts to shape that form. We also study how urban development can be simulated, and how simulation can be controlled and polished to meet artistic needs. Next, we will study the problem of urban content from the game industry's perspective. Each of Electronic Arts' frequently issued editions of Need For Speed requires several urban environments. We will study the artistic and industry constraints that must shape these environments, how existing procedural tools help EA develop them, and how the tools should improve in the future to meet EA's needs.

Sir Arthur Evans was the first official excavator of Knossos, and his legacy is centred on his imaginative creation of Minoan society as a peaceful monarchy of liberal, goddess-worshipping people. Evans' interpretations and reconstructions, based on his excavations of the court complex at Knossos, have proven difficult to move beyond, despite much scholarly work aimed at dismantling his legacy in order to extract aspects of our understanding of Minoan society that have been dependent on his misleading, biased, or erroneous views. I propose a new, holistic approach to analyzing Evans' legacy data that incorporates access analysis, proxemics, and embodied archaeology. The aim of this approach is to contextualize a particular group of related artifacts from Evans' excavations in order to facilitate analyses that might offer new interpretations of the evidence from Knossos, or perhaps confirm Evans' initial conclusions. As a case study I analyze the Miniature Frescoes from the Neopalatial period at the court complex of Knossos, and incorporate the use of experimental archaeology, specifically an experiment designed to analyze the sensory aspects of the context. Based on my reanalysis, I conclude that the court complex at Knossos may have been a ritual centre for the regional community, and that the room where the fragments of the Miniature Frescoes were discovered may have been a location of preparation for these community events, especially considering the location of this room adjacent to both the Central Court and the North Entrance Passageway. I therefore show that new insights can be gained from engaging in a contextualizing study of legacy data, and that these insights can inform an updated interpretation of the material evidence from Knossos.

The paper regards specific context of public spaces in "shadow" of tall buildings located in European cities. Majority of tall buildings in European cities were built in last 15 years. Tall buildings appear mainly in city centres, directly at important public spaces being viable environment for inhabitants with variety of public functions (open spaces, green areas, recreation places, shops, services etc.). All these amenities and services are under direct impact of extensive shading coming from the tall buildings. The paper focuses on analyses and representation of impact of shading from tall buildings on various public spaces in cities using 3D city models. Computer environment of 3D city models in cityGML standard uses 3D LiDAR data as one of data types for definition of 3D cities. The structure of cityGML allows analytic applications using existing computer tools, as well as developing new techniques to estimate extent of shading coming from high-risers, affecting life in public spaces. These measurable shading parameters in specific time are crucial for proper functioning, viability and attractiveness of public spaces-finally it is extremely important for location of tall buildings at main public spaces in cities. The paper explores impact of shading from tall buildings in different spatial contexts on the background of using cityGML models based on core LIDAR data to support controlled urban development in sense of viable public spaces. The article is prepared within research project 2TaLL: Application of 3D Virtual City Models in Urban Analyses of Tall Buildings, realized as a part of Polish-Norway Grants.

Today's spatially aware users are becoming more interested in retrieving personalised and task relevant information, requiring detailed 3D city models linked to non-spatial attribute data. However, current implementations of 3D city models are typically LoD2 that don't include geometric or attribute details about many visible features (e.g. rooms) of a building. As such, valueadded applications developed for web-based and wireless platforms are limited to querying for available non-spatial business data at the building level only. To overcome this, geometrically accurate 3D building models are necessary to enable users to visualize, interact, and query for task specific non-spatial business data. This paper proposes a workflow for creating detailed 3D building models with LoD3 from TLS data and uploading these models into Google Earth so that users can then explore the non-spatial business data of a building and its sub-components (e.g. windows, doors, rooms). Processing bottlenecks of the proposed workflow for detailed 3D building reconstruction are also discussed.

Today's spatially aware users are becoming more interested in retrieving personalised and task relevant information, requiring detailed 3D city models linked to non-spatial attribute data. However, current implementations of 3D city models are typically LoD2 that don't include geometric or attribute details about many visible features (e.g. rooms) of a building. As such, valueadded applications developed for web-based and wireless platforms are limited to querying for available non-spatial business data at the building level only. To overcome this, geometrically accurate 3D building models are necessary to enable users to visualize, interact, and query for task specific non-spatial business data. This paper proposes a workflow for creating detailed 3D building models with LoD3 from TLS data and uploading these models into Google Earth so that users can then explore the non-spatial business data of a building and its sub-components (e.g. windows, doors, rooms). Processing bottlenecks of the proposed workflow for detailed 3D building reconstruction are also discussed.

Figure 1: We propose a system which gives the user full artistic control over rule-based procedural models. With our system, an artist created building designs showcasing architectural styles in Tel Aviv based on reference imagery (left). The artist authored one basic rule set (middle left) where local edits enabled him to quickly reconstruct an existing building (middle right) or design a new alternative (right). By using local edits, the artist was able to create a large amount of detailed building designs in a matter of hours rather than days (bottom).

The paper reviews the state-of-the-art in 3D city models and building block generation, with a description of the most common solutions and approaches. Then the digital reconstruction and comparison of LoD1 and LoD2 building models obtained with commercial packages and using different input data are presented. As input data, a DSM at 1m resolution derived from a GeoEye-1 stereo-pair, a DSM from an aerial block at 50 cm GSD and a LiDAR-based DSM at 1m resolution are used. The geometric buildings produced with each dataset are evaluated with respect to some ground-truth measurements but also compared between them. Problems such as the quality of the input DSM , the accuracy of the necessary vector datasets containing the building footprints, the flexibility of the approaches and the potentialities of each dataset will be discussed. As reconstruction of the building models is largely influenced by the quality of the building footprints, which may be out-of-date or slightly shifted with respect to the employed DSM s/DTM s, an in-house method is being developed to derive them starting from the produced DSM s.

As virtual cities become ever more common and more extensive, the need to populate them with virtual pedestrians grows. One of the problems to be resolved for the virtual population is the behaviour simulation. Currently specifying the behaviour requires a lot of laborious work. In this paper we propose a method for automatically deriving the high level behaviour of the avatars. We introduce to the Graphics community a new method adapted from ideas recently presented in the Architecture literature. In this method, the general avatar movements are derived from an analysis of the structure of the architectural model. The analysis tries to encode Gibson’s 7 principle of affordance, interpreted here as: pedestrians are more attracted towards directions with greater available walkable surface. We have implemented and tested the idea in a 2x2 km 2 model of the city of Nicosia. Initial results indicate that the method, although simple, can automatically and efficiently populate the model w...

Due to the complex nature of urban space and the multitude of interests vested in it, urban design can be described as a complex system. Various disciplines are involved in the analysis and development of urban space. In this respect, collaboration is key in creating socially and physically sustainable urban design. This paper, using a student workshop as a point of departure, discusses the potentials of parametric design as a methodological approach in collaborative urban design between disciplines and with non-professionals.

This paper discusses the formalization of Alternative Shaper, a Spatial Grammar supplemented with procedural knowledge for supporting design generation. The nondeterministic process style perspective supports an exploratory and flexible specification of designs and the use of predicates relating shapes allow the confirmation of shape spatial restrictions on design processes. Although simple at this stage, Alternative Shaper actually offers interesting potentialities on design generation that may be improved soon with convenient abstractions.