The work described in this thesis is part of the initial development of the open-source visualization software OpenSpace, a collaborative project between Linköping University (LiU), the National Aeronautics and Space Administration (NASA) and the American Museum of Natural History (AMNH). The report covers the background and implementation of a rendering system that enables OpenSpace to interactively visualize multiple overlapping space weather events. The system works much like a Deferred Renderer by rendering all objects once and then resolves the final image in a second rendering step. To render a mix of opaque and translucent objects and volumes simultaneously, order-independent transparency solutions are implemented. Performance is compared against traditional methods and possible improvements are discussed. The implemented rendering system is currently powering the OpenSpace visualizations, this gives scientists an interactive tool for studying multiple space weather events, education and public outreach.

A numerical simulation case involving space plasma and the evolution of instabilities that generates very fast electrons, i.e. approximately at half of the speed of light, is used as a test bed for scientific visualisation techniques. A visualisation system was developed to provide interactive real-time animation and visualisation of the simulation results. The work focuses on two themes and the integration of them. The first theme is the storage and management of the large data sets produced. The second theme deals with how the Visualisation System and Visual Objects are tailored to efficiently visualise the data at hand. The integration of the themes has resulted in an interactive real-time animation and visualisation system which constitutes a very powerful tool for analysis and understanding of the plasma physics processes. The visualisations contained in this work have spawned many new possible research projects and provided insight into previously not fully understood plasma physics phenomena.

In the research of developing arbitrary and unique virtual views from a real- world scene, a prototype of an interactive relief texture mapping system capable of processing video using dynamic image-based rendering, is developed in this master thesis. The process of deriving depth from recorded video using binocular stereopsis is presented, together with how the depth information is adjusted to be able to manipulate the orientation of the original scene. When the scene depth is known, the recorded organic and dynamic objects can be seen from viewpoints not available in the original video.

Au cours des deux dernières décennies, les applications temps réel ont montré des améliorations colossales dans la génération de rendus photoréalistes. Cela est principalement dû à la disponibilité de modèles 3D avec une quantité croissante de détails. L'approche traditionnelle pour représenter et visualiser des objets 3D hautement détaillés est de les décomposer en un maillage basse fréquence et une carte de déplacement encodant les détails. La tessellation matérielle est le support idéal pour implémenter un rendu efficace de cette représentation. Dans ce contexte, nous proposons une méthode générale pour la génération et le rendu de maillages multi-résolutions compatibles avec la tessellation matérielle. Tout d'abord, nous introduisons une métrique dépendant de la vue capturant à la fois les distorsions géométriques et paramétriques, permettant de sélectionner la le niveau de résolution approprié au moment du rendu. Deuxièmement, nous présentons une nouvelle représentation hiérarchique permettant d'une part des transitions temporelles et spatiales continues entre les niveaux et d'autre part une tessellation matérielle non uniforme. Enfin, nous élaborons un processus de simplification pour générer notre représentation hiérarchique tout en minimisant notre métrique d'erreur. Notre méthode conduit à d'énormes améliorations tant en termes du nombre de triangles affiché qu'en temps de rendu par rapport aux méthodes alternatives. / In the last two decades, real-time applications have exhibited colossal improvements in the generation of photo-realistic images. This is mainly due to the availability of 3D models with an increasing amount of details. Currently, the traditional approach to represent and visualize highly detailed 3D objects is to decompose them into a low-frequency mesh and a displacement map encoding the details. The hardware tessellation is the ideal support to implement an efficient rendering of this representation. In this context, we propose a general framework for the generation and the rendering of multi-resolution feature-aware meshes compatible with hardware tessellation. First, we introduce a view-dependent metric capturing both geometric and parametric distortions, allowing to select the appropriate resolution at rendertime. Second, we present a novel hierarchical representation enabling on the one hand smooth temporal and spatial transitions between levels and on the other hand a non-uniform hardware tessellation. Last, we devise a simplification process to generate our hierarchical representation while minimizing our error metric. Our framework leads to huge improvements both in terms of triangle count and rendering time in comparison to alternative methods.

Hypertext markup language 5 (HTML5), a new standard for HTML, enriched with additional features is expected to override all the basic underlying overhead needed by other applications. By the advent of new extension, HTML5, the web’s basic language is transplanted from a simple page layout into rich web application development language. Furthermore, with the release of HTML5, traditional browsing is expected to change and modify accordingly and on the other hand the potential users will have an alternative rather than sticking in platform and OS dependent native applications. This thesis deals with the readiness assessment of HTML5 with regard to different smart phones- Android and Windows. In order to visualize the fact, we analyzed different constraints like DNS lookup time, page loading time, memory and CPU consumption associated with two applications-Flash and HTML5 running right through the smart phones. Furthermore, the comparative analysis is performed in different network scenarios- Wi-Fi and 3G and user experience is estimated based on network parameters. From the experiments and observations taken, we found that android phones provide better support for HTML5 web applications than windows mobile devices. Also, the HTML5 applications loading time is limited by the browser rendering time rather that the content loading time from the network and is also dependent on hardware configuration of device used.

It is a great challenge to develop a computer game. Today many games are developed in large game studios where lots of skilled people are working together. Everyone has to know what the final game should look like. Game designers are responsible for how the game should feel and look like. This also means that they decide if a programmer has to develop new techniques or not. Sometimes the game designers require lots of new techniques to be developed. Such a new technique may be rendering particle systems with a lot of particles in it. This is where this report will focus. To render particle systems it is necessary to know about the limitations there are in both hardware and software. Until today particle systems have been updated and calculated using the Central Processing Unit of the computer. With Microsoft Direct3D 10 there are new ways to render particles using Geometry Shaders. Geometry Shaders runs on the graphics card. This thesis focuses on testing rendering performance between using Geometry Shaders and not using Geometry Shaders. A questionnaire was sent to Swedish game developers to get more information about relevant topics for investigation. A general answer was that Geometry Shaders always increase particle rendering performance. This thesis investigates if and when the statement is true or not. The hypothesis was obtained from the answers to the questionnaire. Two test applications were used to investigate if the hypothesis was true or false. One test application has particle calculations on the CPU of the computer. The other test application has particle calculations on the GPU of the graphics card. Six different tests were done and the Geometry Shader approach went out to be the fastest in five of the tests. Since not all tests were faster than the CPU approach the hypothesis is not always true.

The game industry have always looked for rendering techniques that makes the games as good looking and realistic as possible. The common approach is to use triangles built up by vertices and apply many different techniques to make it look as good as possible. When triangles are used to draw objects, there is always edges and those edges often make the objects look less realistic than desired. To reduce these visible edges the amount of triangles for an object have to be increased, but with more triangles more processing power from the graphics cards is needed. Another way to approach rendering is ray tracing which can render an extremely photo realistic image but to the cost of unbearable low performance if you would use it in a realtime application. The reason raytracing is so slow is the massive amount of calculations that needs to be made. In DirectX 11 a few new shaders where announced and one of them were the compute shader, the compute shader allows you to calculate data on the graphics card which is not bound to the pipeline. The compute shader allows you to use the hundreds of cores that the graphic card has and is therefore well suited for a raytracing algorithm. One application is used to see if the hypothesis is correct. A flag is used to define if the application runs on the CPU and the GPU. The same algorithm is used in both versions. Three test where done on each processing unit to confirm the hypothesis. Three more tests where done on the GPU to see how the performance scaled on the GPU depending on the number of rendered objects. The tests proved throughout that the compute shader performs considerably better than the CPU when running our ray tracing algorithm.

Drawing sketches is certainly one of the most important but at the same time elaborate parts of archaeological work. Currently, 3D scanning technology is affording a number of new applications, and only one of them is using virtual copies instead of the originals as the basis for documentation. Our major contribution are methods for automatically generating stylized images from 3D models. These are not only intuitive and easy to read but also more objective and accurate than traditional drawings. Besides some other useful tools we show several examples from our daily work proving that the system accelerates the whole documentation process considerably.

Aus der Einleitung: "Klassische VR/AR-Ausgabegeräte sind meist kopfgetragene Systeme oder 3D-Projektionsanlagen. In bestimmten Anwendungsfällen, zum Beispiel in der Wartung (Schreiber 2011) oder auch in Bauplanung und Bauausführung (Woodward 2011), verbieten sich diese Geräte aufgrund von Arbeitsschutzbestimmungen oder widrigen Einsatzbedingungen. Hier bieten sich Smartphones oder auf ähnlicher Technologie arbeitende Tablett-Computer als Alternative an, insbesondere dann, wenn stereoskopische Darstellung nicht benötigt wird."

This thesis evaluates and tests different methods utilized to produce a 2D aesthetic within a 3D pipeline, as in, converting 3D geometry to an aesthetic that is similar to hand-drawn classic films such as Snow White And The Seven Dwarfs. This thesis explores methods to produce both exterior and interior lines that indicate shape and form of 3D models, the conclusion from the tested methods leaves with the statement that it is unlikely the human factor will be ever entirely replaced by automated solutions, and instead a mixed approach with shader relied solutions and involvement of texturing techniques which provides artistic controls where necessary, is deemed to be the most effective way of preserving the hand-drawn 2D aesthetic within a 3D-pipeline.