Outlined is a new approach to the problem of surfacing particle-based fluid simulations. The key idea is to construct a surface that is as smooth as possible while remaining faithful to the particle locations. We describe a mesh-based algorithm that expresses the surface in terms of a constrained optimization problem. Our algorithm incorporates a secondary contribution in Marching Tiles, a generalization of the Marching Cubes isosurfacing algorithm. Marching Tiles provides guarantees on the minimum vertex valence, making the surface mesh more amenable to numerical operators such as the Bilaplacian.

The Hubble Space Telescope has provided the world with incredible imagery of the surrounding universe. The aesthetic quality of this imagery is limited by production resources; by creating a method to harness the highly refined detail and quality of CG elements in live-action films, we can inspire and educate at a much greater level. In this thesis, I create a rendering approach that allows camera movement around and through elements such as nebulae and galaxies, creating a more cinematic experience. The solution will also allow for reasonable scientific accuracy, visual appeal, efficiency, and extendability to other astronomical visualizations. 3D meshes are constructed and textured using telescopic images as reference. Splats are volumetrically generated using a voxelized bounding box around the mesh. Valid splats within a user specified maximum distance receive initial color and alpha values from the texture map. Probability density functions are used to create a density falloff along the edges of the object, and modifications to the RGBA values are made to achieve the desired cloud-like appearance. The data sets are rendered using a C program developed at the Space Telescope Science Institute by Dr. Frank Summers. The methodology is applied to the test cases of a nebula, star-forming region Sharpless 2-106, and a galaxy, Messier 51, or the Whirlpool Galaxy. The results of this thesis demonstrate the visual, scientific, and technical success of this solution. The code developed during this project generates the desired imagery with reasonable efficiency. A short animation moving from outside the galaxy to a close up of the nebula exhibits the flexibility in scale and camera movement. A careful balance between scientific accuracy and visual appeal were maintained through consultation with astronomers at the Space Telescope Science Institute. The favorable efficient, flexible, visual, and scientific results presented by this work make this process extendable to most other cases of nebula and galaxy visualizations.

Global illumination techniques are used to improve the realism of 3D scenes. Calculating accurate global illumination requires a method for solving the rendering equation. However, the integral form of this equation cannot be evaluated. This thesis presents research in non real-time illumination techniques which are evaluated with a finite number of light rays. This includes a new technique which improves realism of the scene over traditional techniques. All computer rendering requires distortion free texture mapping to appear plausible to the eye. Inverse texture mapping, however, can be numerically unstable and computationally expensive. Alternative techniques for texture mapping and texture coordinate generation were developed to simplify rendering. Real-time rendering is improved by pre-calculating non real-time reflections. The results of this research demonstrate that a polynomial approximation of reflected light can be more accurate than a constant approximation. The solution improves realism and makes use of new features in graphics hardware.

In this dissertation I examine how research in non-photorealistic rendering, human perception, and game-based learning can be combined to produce illustrative simulations of different visual systems that effectively convey information about vision to unprimed observers. The Visual Differences Simulation (VDS) methodology and framework that I propose is capable of producing simulations of animal visual systems based on how they relate to human vision, and can represent differences in color vision, hyperspectral sensitivity, visual acuity, light sensitivity, field of view, motion sensitivity, and eye construction. The simulations produced by the VDS framework run in real time, allowing users to explore computer-generated environments from `behind the eyes' of an animal in an interactive and immersive manner. I also examine how cognitive principles and game-based learning can be leveraged to demonstrate and enhance the educational impact of the simulations produced by the VDS framework. Two case studies are presented, where simulations of the cat and the bee visual systems are used as the basis to design educational games, and are evaluated to show that embedding the simulations in educational games is an effective and engaging way to convey information about vision to unprimed observers. / Graduate

Global illumination techniques are used to improve the realism of 3D scenes. Calculating accurate global illumination requires a method for solving the rendering equation. However, the integral form of this equation cannot be evaluated. This thesis presents research in non real-time illumination techniques which are evaluated with a finite number of light rays. This includes a new technique which improves realism of the scene over traditional techniques. All computer rendering requires distortion free texture mapping to appear plausible to the eye. Inverse texture mapping, however, can be numerically unstable and computationally expensive. Alternative techniques for texture mapping and texture coordinate generation were developed to simplify rendering. Real-time rendering is improved by pre-calculating non real-time reflections. The results of this research demonstrate that a polynomial approximation of reflected light can be more accurate than a constant approximation. The solution improves realism and makes use of new features in graphics hardware.

Outlined is a new approach to the problem of surfacing particle-based fluid simulations. The key idea is to construct a surface that is as smooth as possible while remaining faithful to the particle locations. We describe a mesh-based algorithm that expresses the surface in terms of a constrained optimization problem. Our algorithm incorporates a secondary contribution in Marching Tiles, a generalization of the Marching Cubes isosurfacing algorithm. Marching Tiles provides guarantees on the minimum vertex valence, making the surface mesh more amenable to numerical operators such as the Bilaplacian.

The main purpose of this research project was to implement a combination of computer graphics and processing to generate displays that will aid in the visualization of the colour rendering properties of a range of light sources, including the new generation of high-output LEDs (light emitting diodes) that are becoming widely adopted in general lighting service. The CIE (International Commission on Illumination) has developed a colour appearance model CIECAM02 for use in colour imaging and colour management, and this model is utilized in this work. This thesis describes the design and construction of a computer-based model that can be used as a research tool for the simulation and demonstration of the colour rendering properties of various artificial light sources. It is a comprehensive study of the colour models and measurement procedures currently in use in the lighting industry, as recommended by the CIE. This research project focused on the display of a set of surface colour patches as if they were illuminated by a specific light source, and the simultaneous display of two such sets to demonstrate the surface colour differences arising from the use of the two different light sources. A VIS (virtual imaging system) has been developed to display the colour properties of a series of test colour samples under different light sources. This thesis describes the computer models developed for the representation and display of surface colours in general, and colour rendering in particular. The designed system computes and displays the colour of each sample from a knowledge of the light-source spectrum and the spectral reflectance of each surface. It can simultaneously display the colours resulting from illumination by two different sources. In addition, the system computes the colour appearance differences for two sets of colours using the CIECAM02 colour appearance model. Subjective and objective tests were taken to validate the computed results. The VIS has been designed and implemented. It also has been tested by 21 observers and we believe that it will be a powerful research tool for the lighting industry, especially in relation to colour rendering.

Includes bibliographical references (p. 106-115).

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 47-48). Also available on the Internet.

Thesis (M.F.A.)--Rochester Institute of Technology, 1996. / Typescript. Includes bibliographical references.