Layered Models for Large Scale Time-Evolving Landscapes

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Université Grenoble Alpes
The development of new technologies and algorithms allows the interactive visualization of virtual worlds showing an increasing amount of details and spatial extent. The production of plausible landscapes within these worlds becomes a major challenge, not only because the important part that terrain features and ecosystems play in the quality and realism of 3D sceneries, but also from the editing complexity of large landforms at mountain range scales. Interactive authoring is often achieved by coupling editing techniques with computationally and time demanding numerical simulation, whose calibration is harder as the number of non-intuitive parameters increases. This thesis develops new methods for the simulation of large-scale landscapes. Our goal is to improve both the control and the realism of the synthetic scenes. Our strategy to increase the plausibility consists of building our methods on physically and geomorphologically-inspired laws: we develop new numerical methods, which, combined with intuitive control tools, improve user experience. By observing phenomena triggered by compression areas within the Earth's crust, we propose a method for the intuitive control of the uplift based on a metaphor on the sculpting of the tectonic plates. Combined with new efficient methods for fluvial and glacial erosion, this allows for the fast sculpting of large mountain ranges. In order to visualize the resulting landscapes withing human sight, we demonstrate the need of combining the simulation of various phenomena with different time spans, and we propose a stochastic simulation technique to solve this complex cohabitation. This methodology is applied to the simulation of geological processes such as erosion interleaved with ecosystems formation. This method is then implemented on the GPU, combining long term effects (snowfall, phase changes of water) with highly dynamics ones (avalanches, skiers impact). Our methods allow the simulation of the evolution of large scale, visually plausible landscapes, while accounting for user control. These results were validated by user studies as well as comparisons with data obtained from real landscapes.