375 research outputs found
Beyond factual to formulated silhouettes
When sketching terrain, a view-dependent framework of silhouette-related cues is required. This framework is prominent in manual sketches and is especially important in small-scale depictions viewed obliquely from above. Occluding contours, namely the lines delineating depth discontinuities in the projected surface, are insufficient for forming this framework. The role which the occluding contour, or Factual Silhouette, plays in structuring the sketch becomes increasingly minimal as more of the terrain becomes visible, as the viewpoint is raised.The aim of this research is to extend the set of occluding contours to encompass situations that are perceived as causing an occlusion and would therefore be sketched in a similar manner. These locations, termed Formulated Silhouettes supplement the set of occluding contours and provide a successful structuring framework. The proposed method processes visible areas of terrain, which are turning away from view, to extract a classified, vector-based description for a given view of a Digital Elevation Model. Background approaches to silhouette rendering are reviewed and the specific contributions of this thesis are discussed.The method is tested using case studies composed of terrain of varying scale and character and two application studies demonstrate how silhouettes can be used to enhance existing terrain visualization techniques, both abstract and realistic. In addition, consultation with cartographic designers provides external verification of the research. The thesis concludes by noting how silhouette contours relate to perceived entities rather than actual occlusions
The Visvalingam algorithm: metrics, measures and heuristics
This paper provides the background necessary for a clear understanding of forthcoming papers relating to the Visvalingam algorithm for line generalisation, for example on the testing and usage of its implementations. It distinguishes the algorithm from implementation-specific issues to explain why it is possible to get inconsistent but equally valid output from different implementations. By tracing relevant developments within the now-disbanded Cartographic Information Systems Research Group (CISRG) of the University of Hull, it explains why a) a partial metric-driven implementation was, and still is, sufficient for many projects but not for others; b) why the Effective Area (EA) is a measure derived from a metric; c) why this measure (EA) may serve as a heuristic indicator for in-line feature segmentation and model-based generalisation; and, d) how metrics may be combined to change the order of point elimination. The issues discussed in this paper also apply to the use of other metrics. It is hoped that the background and guidance provided in this paper will enable others to participate in further research based on the algorithm
Art in scientific visualization of terrain data
This is a record of an invited exhibition on pioneering research on non-photorealistic animation posted by Mahes Visvalingam at the Royal Institution (UK) to accompany the Friday Evening Discourses on : Where Art Meets Science by Lord Puttnam of Enigma Productions, NESTA on 5 November 1999 The Information Age : Public and Personal by Dr J M Taylor, Director General of Research Councils, Office of Science and Technology on 17 March 200
Expressive rendering of mountainous terrain
technical reportPainters and cartographers have developed artistic landscape rendering techniques for centuries. Such renderings can visualize complex three-dimensional landscapes in a pleasing and understandable way. In this work we examine a particular type of artistic depiction, panorama maps, in terms of function and style, and we develop methods to automatically generate panorama map reminiscent renderings from GIS data. In particular, we develop image-based procedural surface textures for mountainous terrain. Our methods use the structural information present in the terrain and are developed with perceptual metrics and artistic considerations in mind
Terrain Sketching
Procedural methods for terrain synthesis are capable of creating realistic depictions of heightfield terrains with little user intervention. However, users often do wish to intervene in controlling the placement and shape of landforms, but without sacrificing realism. In this paper, we present a sketching interface to procedural terrain generation. This system enables users to draw the silhouette, spine and bounding curves of both extruding (hills and mountains) and embedding landforms (river courses and canyons). Terrain is interactively generated to match the sketched constraints using multiresolution surface deformation. In addition, the wavelet noise characteristics of silhouette strokes are propagated to the surrounding terrain. With terrain sketching users can interactively create or modify landscapes incorporating varied and complex landforms
Scalable visualization of spatial data in 3D terrain
Designing visualizations of spatial data in 3D terrain is challenging because various heterogeneous data aspects need to be considered, including the terrain itself, multiple data attributes, and data uncertainty. It is hardly possible to visualize these data at full detail in a single image. Therefore, this thesis devises a scalable visualization approach that focuses on relevant information to be emphasized, while less-relevant information can be attenuated. In this context, a noval concept of visualizing spatial data in 3D terrain and different soft- and hardware solutions are proposed.Die Erstellung von Visualisierungen fĂŒr rĂ€umliche Daten im 3D-GelĂ€nde ist schwierig, da viele heterogene Datenaspekte wie das GelĂ€nde selbst, die verschiedenen Datenattribute sowie Unsicherheiten bei der Darstellung zu berĂŒcksichtigen sind. Im Allgemeinen ist es nicht möglich, diese Datenaspekte gleichzeitig in einer Visualisierung darzustellen. Daher werden in der Arbeit skalierbare Visualisierungsstrategien entwickelt, welche die wichtigen Informationen hervorheben und trotzdem gleichzeitig Kontextinformationen liefern. HierfĂŒr werden neue Systematisierungen und Konzepte vorgestellt
NOT ANOTHER SPACE SUIT: Fusing Technology and Indigenous Solutions To Facilitate Thermal Comfort
Unseen, unheard and unconsidered, Qatarâs migrant worker population is building one of the richest countries in the world. They labor in Qatarâs high heat index1 climate, which is coincidentally comparable to an Oriental sauna, wearing the most rudimentary of clothes. Working up to 60 hours a week, migrant workers fall victim to heat stress and dozens are hospitalized daily, starting as early as March and increasing in numbers during the peak months of June to August. Since clothes are essentially a âsecond skin,â affecting the rate and efficiency with which heat is exchanged between the body and its surroundings, a concept garment was designed to improve thermal comfort. Low-tech, indigenous heat-management systems are combined with new technologies and knowledge of human physiology to design a two-layer suit that aims to optimize heat exchange mechanisms. The suit enhances radiation, convection and evaporation by having a snug-fitting inner wicking layer and a loose-cut outer shell, and by using strategically placed vents, perforations, and Phase Change Material (PCM) packs. Using fiction as a medium of social commentary and critical design, the concept suit borrows from the superhero aesthetic to present the migrant worker in a new light. The suit denotes power, symbolizing the superhuman feat these workers perform and their true worth to the economy. Its aesthetic and function aim to improve worker morale and performance. Mapping, scoping and primary and secondary qualitative and quantitative research have been used throughout the design process. This is in addition to an ethnographic study, field observations, material explorations, body storming and experimentation
Field sketching and the interpretation of landscape : exploring the benefits of fieldwork and drawing in contemporary landscape practice
This thesis explores potential roles for field sketching in, landscape observation and assessment, landscape planning and design, landscape representation, and
in addressing the experiential dimension of the landscape.The research seeks to define and legitimise the old technique of field sketching, and the use and development of field sketches by students and
practitioners of landscape architecture, and other landscape disciplines. The wider values of, fieldwork, hand -generated field notations, drawing as an
interactive dialogue with others, and the sketch as a type of landscape representation, are also recognised.Whilst accurate representation and precise geometrical definition of the landscape can now be achieved quickly with photographs and by semi - automated digital means, interpretation requires careful observation. Sketching
involves an observer stopping and looking and interpreting slowly and carefully. Field sketching and the uses of the field sketch are proposed as bringing an effectiveness to landscape work, valuable because of the interpretation it
involves, and the time it does take: timeless because of its simplicity.A personal way of working is investigated, based on a Grounded Theory approach. Systematic analysis of case studies is made through reflection-on-practice. Practice observations (data) are collated and interpreted by practical
sorting tasks, to propose a series of how to do and why important principles regarding field sketching. External support for the research findings is sought from literature, considering the broad themes of: fieldwork and the experience of landscapes, field sketching and drawing as craft and expression, and developing and using field sketches.Applications for field sketching to meet contemporary needs in landscape architecture are proposed: the sketch as a designer's tool, sketch-based visualisations as interpretive images, and field sketching as a participative technique that can be used to engage the inquirer, collaborators, and the public with landscape experience -grounded decisions
Synthesizing and Editing Photo-realistic Visual Objects
In this thesis we investigate novel methods of synthesizing new images of a deformable visual object using a collection of images of the object. We investigate both parametric and non-parametric methods as well as a combination of the two methods for the problem of image synthesis. Our main focus are complex visual objects, specifically deformable objects and objects with varying numbers of visible parts. We first introduce sketch-driven image synthesis system, which allows the user to draw ellipses and outlines in order to sketch a rough shape of animals as a constraint to the synthesized image. This system interactively provides feedback in the form of ellipse and contour suggestions to the partial sketch of the user. The user's sketch guides the non-parametric synthesis algorithm that blends patches from two exemplar images in a coarse-to-fine fashion to create a final image. We evaluate the method and synthesized images through two user studies. Instead of non-parametric blending of patches, a parametric model of the appearance is more desirable as its appearance representation is shared between all images of the dataset. Hence, we propose Context-Conditioned Component Analysis, a probabilistic generative parametric model, which described images with a linear combination of basis functions. The basis functions are evaluated for each pixel using a context vector computed from the local shape information. We evaluate C-CCA qualitatively and quantitatively on inpainting, appearance transfer and reconstruction tasks. Drawing samples of C-CCA generates novel, globally-coherent images, which, unfortunately, lack high-frequency details due to dimensionality reduction and misalignment. We develop a non-parametric model that enhances the samples of C-CCA with locally-coherent, high-frequency details. The non-parametric model efficiently finds patches from the dataset that match the C-CCA sample and blends the patches together. We analyze the results of the combined method on the datasets of horse and elephant images
Représentation, modélisation et génération procédurale de terrains
Slides disponiblesSoutenance oral (présentation + questions) disponible sur demandeThis PhD (entitled "Representation, modelisation and procedural generation of terrains") is related to movie and videogames digital content creation, especially natural scenes.Our work is dedicated to handle and to generate landscapes efficently. We propose a new model based on a construction tree inside which the user can handle parts of the terrain intuitively. We also present techniques to efficently visualize such model. Finally, we present a new algorithm for generating large-scale terrains exhibiting hierarchical structures based on their hydrographic networks: elevation is generated in a broad compliance to water-tansport principles without having to resort on costly hydraulic simulations.Cette thÚse (qui a pour intitulé "Représentation, modélisation et génération procédurale de terrains") a pour cadre la génération de contenus numériques destinés aux films et aux jeux-vidéos, en particulier les scÚnes naturelles.Nos travaux visent à représenter et à générer des terrains. Nous proposons, en particulier, un nouveau modÚle de représentation qui s'appuie sur un arbre de construction et qui va permettre à l'utilisateur de manipuler des morceaux de terrain de façon intuitive. Nous présentons également des techniques pour visualiser ce modÚle avec un maximum d'efficacité. Enfin nous développons un nouvel algorithme de génération de terrains qui construit de trÚs grands reliefs possédant des structures hiérarchiques découlant d'un réseau hydrographique : le relief généré est conforme aux grands principes d'écoulement des eaux sans avoir besoin d'utiliser de coûteuses simulations d'érosion hydrique
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