Webbapplikationer blir mer och mer avancerade och ställer mer krav på dagens enheter. Rendering av grafik i HTML5 canvas är något som kan ställa stort krav på enheter och en påföljd av detta är att svarstiden blir lång. En eventuell lösning på problemet med bristande prestanda hos enheter är att förflytta renderingen från klientsidan till serversidan. Två versioner av samma webbapplikation skapades där renderingen sker på klientsidan i en version och på serversidan i annan version med hjälp av Node.js. Webbapplikationen renderar diagram som baseras på olika variabler. Tester genomfördes för att jämföra versionerna, där det visade sig att klientversionen var den version som resulterade i lägst svarstid och minst överförd datamängd. Ytterligare tester med större skillnad gällande prestanda och typ för enheter är av intresse för framtida arbete.

Reproduire efficacement l'apparence réaliste des matériaux est un problème crucial pour la synthèse d'images réalistes dans les productions cinématographiques et les jeux vidéo. Outre le transport global de la lumière, le réalisme d'une image de synthèse passe avant tout par une modélisation correcte du transport local, c'est-à-dire les interactions entre lumière et matière. La modélisation de ces interactions donne lieu à une grande variété de modèles de réflectance. Nous proposons une classification de ces modèles en s'appuyant sur l'échelle des détails géométriques abstraits. À partir de cette classification, nous étudions des modèles de réflectance particuliers : * un modèle de transmission pour les surfaces transparentes et rugueuses, tels que le verre dépoli. Son efficacité permet une utilisation au sein applications temps-réel * une analyse et une modélisation du transport de la lumière dans les matériaux composés d'agrégats de particules * une base alternative aux harmoniques sphériques pour représenter et illuminer efficacement les matériaux mesurés ayant une réflectance à basses fréquences. Ces modèles permettent une abstraction efficace des interactions locales tout en conservant la reproduction de leurs effets réalistes. / Reproducing efficiently the appearance of complex materials is a crucial problem in the synthesis of realistic images widely involved in the production of video games and movies. Apart from global light transport, the realism of a synthetic image is in large part due to the adequate modeling of local light transport, i.e. the interactions between light and matter. Modeling these interactions gives rise to a large variety of reflectance models. We therefore propose a classification of these models based on the scales of their abstract geometric details. From this classification, we can study particular reflectance models: a transmitting reflectance model for transparent rough surfaces such a frosted glass. The efficiency of our model allows real-time performances, a study and a model of energy propagation in material composed of dense packed discrete particles, an alternative basis for representing and lighting efficiently measured materials having a low frequency reflectance. These models permit the abstraction of local interactions while keeping the realism of fully simulated local light transport models.

Conhecido pelo seu alto custo computacional e grande qualidade das imagens sintetizadas, o traçado de raios vem sendo mais recentemente explorado pela comunidade científica em pesquisas por uma taxa de quadro interativa e constante. Almejando um novo modo de aceleração do traçado de raios, uma nova abordagem denominada traçado de raios assistido pela unidade de processamento gráfico é apresentada neste trabalho. Seu objetivo é dar base à formulação de algoritmos que façam um uso melhor dos recursos disponíveis nas placas de vídeo frequentemente encontradas nos computadores convencionais atuais. Com base nesta abordagem, várias contribuições são propostas nesta dissertação. Além de apresentar conceitos básicos de traçado de raios e uma revisão literária de seus tópicos mais importantes, este trabalho também explica e exemplifica alguns algoritmos clássicos de traçado de raios que serão utilizados como base para outros algoritmos aqui apresentados. Como principal contribuição é proposto e implementado um algoritmo, que calcula os pontos iniciais de varredura de subdivisões espaciais do traçado de raios primários de mapas de alturas a partir de um distance-buffer (mapa de distâncias) sintetizado pela unidade de processamento gráfico da placa de vídeo. Um segundo algoritmo é também proposto, onde um object-buffer (mapa de objetos) é sintetizado pela placa de vídeo para acelerar a varredura de estruturas de subdivisão espacial em cenas com primitivas genéricas do traçado de raios. Contribuições pontuais são realizadas neste trabalho no campo de síntese de mapas de alturas pela definição dos seguintes algoritmos: o algoritmo de reconstrução bilinear analítica, o algoritmo de interpolação biquadrátrica dupla, o algoritmo de predição por planos de altura inclinados e o algoritmo de mapeamento de nível de detalhe de reconstrução da superfície para o modelo de voxels. Uma breve discussão a respeito do futuro de algoritmos de traçado de raios assistido pela unidade de processamento gráfico e de sua implementação em aglomerados gráficos é apresentada no final deste trabalho, explorando novas possibilidades para a sua continuidade, desencadeando novas linhas de pesquisa correlacionadas. / Known by its high computational cost and by the high quality rendered imagens, ray tracing has been most recently explored by the scientific community in researches for interactive and constant frame rate. Aiming for a new way for optimizing ray tracing, a new approach called GPU-assisted ray tracing is defined in this work. Its objective is to be a first step in the formulation of ray tracing algorithms that take better advantage of graphics processing units commonly found in personal computers nowadays. Based on this approach, several contributions are proposed in this work. Besides presenting the basic concepts for ray tracing and a literature review of the most relevant topics, this work also explains and exemplifies some classical algorithms that are used as a base for the new algorithms here presented. As main contribution, we propose and implement an algorithm that calculates the initial points for traversing spatial subdivision structures, for tracing primary rays in height maps from a distance-buffer rendered by the video card. A second algorithm is proposed as well, where an object-buffer is rendered by the video card to accelerate the traversal of rays in spatial subdivision structures for scenes with generic primitives. Individual contributions are made, in this work, in rendering height maps by defining the following algorithms: the analytic bilinear reconstruction algorithm, the double bi-quadratic interpolation algorithm, the prediction by inclined height planes algorithm and the level of detail mapping for surface reconstruction in voxel-based models algorithm. A brief discussion about the future of GPU-assisted ray tracing algorithms and its implementation in graphical clusters is presented at the end of this work, exploiting new possibilities for its continuation and for related research topics.

The human face is a fascinating, but extremely complex object; the research project described is concerned with the computer generation and animation of faces. However, the age old captivation with the face transforms into a major obstacle when creating synthetic faces. The face and head are the most visible attributes of a person. We master the skills of recognising faces and interpreting facial movement at a very early age. As a result, we are likely to notice the smallest deviation from our concept of how a face should appear and behave. Computer animation in general, is often perceived to be ``wooden' and very ``rigid'; the aim is therefore to provide facilities for the generation of believable faces and convincing facial movement. The major issues addressed within the project concern the modelling of a large variety of faces and their animation. Computer modelling of arbitrary faces is an area that has received relatively little attention in comparison with the animation of faces. Another problem that has been considered is that of providing the user with adequate and effective control over the modelling and animation of the face. The Facial Animation, Construction and Editing System or FACES was conceived as a system for investigating these issues. A promising approach is to look a little deeper than the surface of the skin. A three-layer anatomical model of the head, which incorporates bone, muscle, skin and surface features, has been developed. As well as serving as a foundation which integrates all the facilities available within FACES, the advantage of the model is that it allows differing strategies to be used for modelling and animation. FACES is an interactive system, which helps with both the generation and animation of faces, while hiding the structural complexities of the face from the user. The software consists of four sub-systems; CONSTRUCT and MODIFY cater for modelling functionality, while ANIMATE allows animation sequences to be generated and RENDER provides for shading and motion evaluation.

Spectral rendering, or the synthesis of images by taking into account the wavelengths of light, allows effects otherwise impossible with other methods. One of these effects is dispersion, the phenomenon that creates a rainbow when white light shines through a prism. Spectral rendering has previously remained in the realm of off-line rendering (with a few exceptions) due to the extensive computation required to keep track of individual light wavelengths. Caustics, the focusing and de-focusing of light through a refractive medium, can be interpreted as a special case of dispersion where all the wavelengths travel together. This thesis extends Adaptive Caustic Mapping, a previously proposed caustics mapping algorithm, to handle spectral dispersion. Because ACM can display caustics in real-time, it is quite amenable to be extended to handle the more general case of dispersion. A method is presented that runs in screen-space and is fast enough to display plausible dispersion phenomena in real-time at interactive frame rates.

Cette thèse s'inscrit dans le thème du rendu expressif qui vise à définir des outils de création et de traitement d'images ou d'animations stylisées. Les applications concernent tous les métiers nécessitant une représentation visuelle plus stylisée qu'une photographie : création artistique (jeux vidéo, film d'animation, dessins animés), restitution archéologique, documentation technique, etc. Un critère fondamental de qualité d'une image est l'absence d'artefacts visuels. Cette considération a toujours existé, mais elle est particulièrement importante dans le cas de l'informatique graphique. En effet, la nature même de l'image – des pixels discrets – est source d'artefacts. Les artefacts sont encore plus visibles lorsque l'on s'intéresse aux animations, des artefacts temporels s'ajoutant aux artefacts spatiaux. L'objectif de cette thèse est d'une part de formaliser et mesurer ces artefacts en tenant compte de la perception humaine, et d'autre part de proposer de nouvelles méthodes de stylisation interactive d'animations 3D. Nous présentons tout d'abord un ensemble de techniques pour créer et assurer la cohérence de dessins au trait extraits de scènes 3D animées. Nous proposons ensuite deux méthodes de stylisation des régions de couleur permettant la créations d'un grand nombre de motifs. Le point commun à toutes ces approches est la représentation du médium simulé (pigment d'aquarelle, coup de crayon ou de pinceau...) par une texture évoluant au cours de l'animation. Nous décrivons enfin deux expériences utilisateurs visant à évaluer perceptuellement la qualité des résultats produits par ce type de techniques. / This PhD thesis deals with expressive rendering, a sub-field of computer graphics which aims at defining creation and processing tools to stylize images and animations. It has applications in all the fields that need depictions more stylized than photographs, such as entertainment (e.g., video games, animated films, cartoons), virtual heritage, technical illustration, etc. A crucial criterion to assert the quality of an image is the absence of visual artifacts. While already true for traditional art, this consideration is especially important in computer graphics. Indeed the intrinsic discrete nature of an image can lead to artifacts. This is even more noticeable during animations, as temporal artifacts are added to spatial ones. The goal of this thesis is twofold: (1) To formalize and measure these artifacts by taking into account human perception; (2) To propose new interactive methods to stylize 3D animations. First we present a set of techniques to ensure the coherence of line drawings extracted form 3D animated scenes. Then we propose two methods to stylize shaded regions, which allow to create a wide variety of patterns. The shared ground layer of all these approaches is the use of temporally varying textures to represent the simulated media (e.g., watercolor pigments, brush strokes). Finally we describe two user studies aiming at evaluating the quality of the results produced by such techniques.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: p. 104-109. / There are two distinguishable parts to this thesis. Part I is a discourse on architectural representation. It defines the theoretical boundary for Part II, research on a particular spatial representation system, physical models, and their use as a design aid. In Part I, representation is discussed as it pertains to the design process. An opinion is built around the excessive 'visual' nature of the topic. The many types of representation systems are described. Finally, a brief historical survey, as well as two current design processes provide insight into applications of these systems. Part II is the documentation of a research project that attempts to visualize physical phenomena (energy behavior) as they act on physical models representative of architectural form. A statement is put forth postulating a design approach that addresses energy behavior in a 'qualitative' sense based on its comprehension through these established visualization techniques. A procedure for testing physical phenomena on models is described and finally, the documentation of such tests for wind, solar shading, convection and light are presented. A conclusion forecasts potential applications of this research. The multi-disciplinary exploration of visual communications and energy conscious design is addressed in the content, as well as the communicative technique and medium of this presentation. The author is responsible for reproducing all the images in this book. Reproductions from other sources were copied photographically. In its original form several pages were printed in offset. This process was completed entirely by the author, from original photograph to pasteup, printing preparation and running the press. An experimental video production is being prepared as well. / by Donald Alberto. / M.S.

Conhecido pelo seu alto custo computacional e grande qualidade das imagens sintetizadas, o traçado de raios vem sendo mais recentemente explorado pela comunidade científica em pesquisas por uma taxa de quadro interativa e constante. Almejando um novo modo de aceleração do traçado de raios, uma nova abordagem denominada traçado de raios assistido pela unidade de processamento gráfico é apresentada neste trabalho. Seu objetivo é dar base à formulação de algoritmos que façam um uso melhor dos recursos disponíveis nas placas de vídeo frequentemente encontradas nos computadores convencionais atuais. Com base nesta abordagem, várias contribuições são propostas nesta dissertação. Além de apresentar conceitos básicos de traçado de raios e uma revisão literária de seus tópicos mais importantes, este trabalho também explica e exemplifica alguns algoritmos clássicos de traçado de raios que serão utilizados como base para outros algoritmos aqui apresentados. Como principal contribuição é proposto e implementado um algoritmo, que calcula os pontos iniciais de varredura de subdivisões espaciais do traçado de raios primários de mapas de alturas a partir de um distance-buffer (mapa de distâncias) sintetizado pela unidade de processamento gráfico da placa de vídeo. Um segundo algoritmo é também proposto, onde um object-buffer (mapa de objetos) é sintetizado pela placa de vídeo para acelerar a varredura de estruturas de subdivisão espacial em cenas com primitivas genéricas do traçado de raios. Contribuições pontuais são realizadas neste trabalho no campo de síntese de mapas de alturas pela definição dos seguintes algoritmos: o algoritmo de reconstrução bilinear analítica, o algoritmo de interpolação biquadrátrica dupla, o algoritmo de predição por planos de altura inclinados e o algoritmo de mapeamento de nível de detalhe de reconstrução da superfície para o modelo de voxels. Uma breve discussão a respeito do futuro de algoritmos de traçado de raios assistido pela unidade de processamento gráfico e de sua implementação em aglomerados gráficos é apresentada no final deste trabalho, explorando novas possibilidades para a sua continuidade, desencadeando novas linhas de pesquisa correlacionadas. / Known by its high computational cost and by the high quality rendered imagens, ray tracing has been most recently explored by the scientific community in researches for interactive and constant frame rate. Aiming for a new way for optimizing ray tracing, a new approach called GPU-assisted ray tracing is defined in this work. Its objective is to be a first step in the formulation of ray tracing algorithms that take better advantage of graphics processing units commonly found in personal computers nowadays. Based on this approach, several contributions are proposed in this work. Besides presenting the basic concepts for ray tracing and a literature review of the most relevant topics, this work also explains and exemplifies some classical algorithms that are used as a base for the new algorithms here presented. As main contribution, we propose and implement an algorithm that calculates the initial points for traversing spatial subdivision structures, for tracing primary rays in height maps from a distance-buffer rendered by the video card. A second algorithm is proposed as well, where an object-buffer is rendered by the video card to accelerate the traversal of rays in spatial subdivision structures for scenes with generic primitives. Individual contributions are made, in this work, in rendering height maps by defining the following algorithms: the analytic bilinear reconstruction algorithm, the double bi-quadratic interpolation algorithm, the prediction by inclined height planes algorithm and the level of detail mapping for surface reconstruction in voxel-based models algorithm. A brief discussion about the future of GPU-assisted ray tracing algorithms and its implementation in graphical clusters is presented at the end of this work, exploiting new possibilities for its continuation and for related research topics.

Xie, Yongming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 77-85). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.ii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Isosurfaces --- p.1 / Chapter 1.2 --- Graphics Processing Unit --- p.2 / Chapter 1.3 --- Objective --- p.3 / Chapter 1.4 --- Contribution --- p.3 / Chapter 1.5 --- Thesis Organization --- p.4 / Chapter 2 --- Marching Cubes --- p.5 / Chapter 2.1 --- Introduction --- p.5 / Chapter 2.2 --- Marching Cubes Algorithm --- p.7 / Chapter 2.3 --- Triangulated Cube Configuration Table --- p.12 / Chapter 2.4 --- Summary --- p.16 / Chapter 3 --- Graphics Processing Unit --- p.18 / Chapter 3.1 --- Introduction --- p.18 / Chapter 3.2 --- History of Graphics Processing Unit --- p.19 / Chapter 3.2.1 --- First Generation GPU --- p.20 / Chapter 3.2.2 --- Second Generation GPU --- p.20 / Chapter 3.2.3 --- Third Generation GPU --- p.20 / Chapter 3.2.4 --- Fourth Generation GPU --- p.21 / Chapter 3.3 --- The Graphics Pipelining --- p.21 / Chapter 3.3.1 --- Standard Graphics Pipeline --- p.21 / Chapter 3.3.2 --- Programmable Graphics Pipeline --- p.23 / Chapter 3.3.3 --- Vertex Processors --- p.25 / Chapter 3.3.4 --- Fragment Processors --- p.26 / Chapter 3.3.5 --- Frame Buffer Operations --- p.28 / Chapter 3.4 --- GPU CPU Analogy --- p.31 / Chapter 3.4.1 --- Memory Architecture --- p.31 / Chapter 3.4.2 --- Processing Model --- p.32 / Chapter 3.4.3 --- Limitation of GPU --- p.33 / Chapter 3.4.4 --- Input and Output --- p.34 / Chapter 3.4.5 --- Data Readback --- p.34 / Chapter 3.4.6 --- FramebufFer --- p.34 / Chapter 3.5 --- Summary --- p.35 / Chapter 4 --- Volume Rendering --- p.37 / Chapter 4.1 --- Introduction --- p.37 / Chapter 4.2 --- History of Volume Rendering --- p.38 / Chapter 4.3 --- Hardware Accelerated Volume Rendering --- p.40 / Chapter 4.3.1 --- Hardware Acceleration Volume Rendering Methods --- p.41 / Chapter 4.3.2 --- Proxy Geometry --- p.42 / Chapter 4.3.3 --- Object-Aligned Slicing --- p.43 / Chapter 4.3.4 --- View-Aligned Slicing --- p.45 / Chapter 4.4 --- Summary --- p.48 / Chapter 5 --- GPU-Friendly Marching Cubes --- p.49 / Chapter 5.1 --- Introduction --- p.49 / Chapter 5.2 --- Previous Work --- p.50 / Chapter 5.3 --- Traditional Method --- p.52 / Chapter 5.3.1 --- Scalar Volume Data --- p.53 / Chapter 5.3.2 --- Isosurface Extraction --- p.53 / Chapter 5.3.3 --- Flow Chart --- p.54 / Chapter 5.3.4 --- Transparent Isosurfaces --- p.56 / Chapter 5.4 --- Our Method --- p.56 / Chapter 5.4.1 --- Cell Selection --- p.59 / Chapter 5.4.2 --- Vertex Labeling --- p.61 / Chapter 5.4.3 --- Cell Indexing --- p.62 / Chapter 5.4.4 --- Interpolation --- p.65 / Chapter 5.5 --- Rendering Translucent Isosurfaces --- p.67 / Chapter 5.6 --- Implementation and Results --- p.69 / Chapter 5.7 --- Summary --- p.74 / Chapter 6 --- Conclusion --- p.76 / Bibliography --- p.77

This thesis describes the process of creating a 3D environment from the initial concept to the final scene. It discusses relevant research into new technology in the field of real-time rendering, including Physically Based Rendering and a synced normals workflow. It examines how the goals of the project changed over time and how the associated challenges were resolved. Conclusions are drawn about what practices were most successful, and how the development process could be improved.