Browsing by Author "Paris, Axel"

Now showing 1 - 3 of 3
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    Desertscapes Simulation
    (The Eurographics Association and John Wiley & Sons Ltd., 2019) Paris, Axel; Peytavie, Adrien; Guérin, Eric; Argudo, Oscar; Galin, Eric; Lee, Jehee and Theobalt, Christian and Wetzstein, Gordon
    We present an interactive aeolian simulation to author hot desert scenery. Wind is an important erosion agent in deserts which, despite its importance, has been neglected in computer graphics. Our framework overcomes this and allows generating a variety of sand dunes, including barchans, longitudinal and anchored dunes, and simulates abrasion which erodes bedrock and sculpts complex landforms. Given an input time varying high altitude wind field, we compute the wind field at the surface of the terrain according to the relief, and simulate the transport of sand blown by the wind. The user can interactively model complex desert landscapes, and control their evolution throughout time either by using a variety of interactive brushes or by prescribing events along a user-defined time-line.
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    Segment Tracing Using Local Lipschitz Bounds
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Galin, Eric; Guérin, Eric; Paris, Axel; Peytavie, Adrien; Panozzo, Daniele and Assarsson, Ulf
    We introduce Segment Tracing, a new algorithm that accelerates the classical Sphere Tracing method for computing the intersection between a ray and an implicit surface. Our approach consists in computing the Lipschitz bound locally over a segment to improve the marching step computation and accelerate the overall process. We describe the computation of the Lipschitz bound for different operators and primitives. We demonstrate that our algorithm significantly reduces the number of field function queries compared to previous methods, without the need for additional accelerating data-structures. Our method can be applied to a vast variety of implicit models ranging from hierarchical procedural objects built from complex primitives, to simulation-generated implicit surfaces created from many particles.
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    Synthesizing Geologically Coherent Cave Networks
    (The Eurographics Association and John Wiley & Sons Ltd., 2021) Paris, Axel; Guérin, Eric; Peytavie, Adrien; Collon, Pauline; Galin, Eric; Zhang, Fang-Lue and Eisemann, Elmar and Singh, Karan
    We present a geologically-based method to generate complex karstic networks. Karsts are a type of landscape formed by the dissolution of highly soluble rocks (generally limestones). In particular, they are characterized by complex underground networks made of varieties of tunnels and breakout chambers with stalagmites and stalactites. Our method computes skeletons of karstic networks by using a gridless anisotropic shortest path algorithm according to field data of the underground system (such as inlets and outlets), geomorphological features and parameters such as faults, inception horizons, fractures, and permeability contrasts. From this skeleton, we define the geometry of the conduits as a signed distance function construction tree combining primitives with blending and warping operators. Our framework provides multiple levels of control, allowing us to author both the structure of the karstic network and the geometric cross-section shapes and details of the generated conduits.