Procedural generation of features for volumetric terrains using a rule-based approach.

Terrain generation is a fundamental requirement of many computer graphics simulations, including computer games, flight simulators and environments in feature films. Volumetric representations of 3D terrains can create rich features that are either impossible or very difficult to construct in other forms of terrain generation techniques, such as overhangs, arches and caves. While a considerable amount of literature has focused on procedural generation of terrains using heightmap-based implementations, there is little research found on procedural terrains utilising a voxel-based approach. This thesis contributes two methods to procedurally generate features for terrains that utilise a volumetric representation. The first method is a novel grammar-based approach to generate overhangs and caves from a set of rules. This voxel grammar provides a flexible and intuitive method of manipulating voxels from a set of symbol/transform pairs that can provide a variety of different feature shapes and sizes. The second method implements three parametric functions for overhangs, caves and arches. This generates a set of voxels procedurally based on the parameters of a function selected by the user. A small set of parameters for each generator function yields a widely varied set of features and provides the user with a high degree of expressivity. In order to analyse the expressivity, this thesis’ third contribution is an original method of quantitatively valuing a result of a generator function. This research is a collaboration with Sony Interactive Entertainment and their proprietary game engine PhyreEngineTM. The methods presented have been integrated into the engine’s terrain system. Thus, there is a focus on real-time performance so as to be feasible for game developers to use while adhering to strict sub-second frame times of modern computer games

Interactive Rendering of Scattering and Refraction Effects in Heterogeneous Media

In this dissertation we investigate the problem of interactive and real-time visualization of single scattering, multiple scattering and refraction effects in heterogeneous volumes. Our proposed solutions span a variety of use scenarios: from a very fast yet physically-based approximation to a physically accurate simulation of microscopic light transmission. We add to the state of the art by introducing a novel precomputation and sampling strategy, a system for efficiently parallelizing the computation of different volumetric effects, and a new and fast version of the Discrete Ordinates Method. Finally, we also present a collateral work on real-time 3D acquisition devices