Interactive Procedural Modelling of Coherent Waterfall Scenes

Abstract

International audienceCombining procedural generation and user control is a fundamental challenge for the interactive design of natural scenery. This is particularly true for modelling complex waterfall scenes where, in addition to taking charge of geometric details, an ideal tool should also provide a user with the freedom to shape the running streams and falls, while automatically maintaining physical plausibility in terms of flow network, embedding into the terrain, and visual aspects of the waterfalls. We present the first solution for the interactive procedural design of coherent waterfall scenes. Our system combines vectorial editing, where the user assembles elements to create a waterfall network over an existing terrain, with a procedural model that parametrizes these elements from hydraulic exchanges; enforces consistency between the terrain and the flow; and generates detailed geometry, animated textures and shaders for the waterfalls and their surroundings. The tool is interactive, yielding visual feedback after each edit

First Person Sketch-based Terrain Editing

“…Our deformation algorithm relies on iterative diffusion of displacement constraints, which are computed from the 3D strokes positioned in the world space. The diffusion method, first introduced by the authors in [8], consists in computing the difference of the curve height and the terrain height H , and to diffuse these differences (instead of absolute height values) using a multi-grid Poisson solver similar to the one in [12].…”

A Review of Digital Terrain Modeling

“…Emilien et al . [EPCV15] provide an interactive editor focused on laying out rivers and waterfalls with attendant sculpting of the underlying base terrain (Figure ). The user employs a set of vector sketching tools to specify segments of a river network graph, both those in contact with the terrain and falling free.…”

Deformation Grammars: Hierarchical Constraint Preservation Under Deformation

“…[JPCC14] extend the previous method to crowd‐patches embedding recomputed crowd animation data; Emilien et al . [EPCV15] maintain the consistency of a waterfall scene under vector‐based design; Longay et al . [LRBP12] allow us to manipulate a realistic tree through sketching and Stanculescu et al .…”

“…Edit-only methods: relax the analyse-and-edit paradigm, allowing the use of consistency criteria which would be very hard to analyse. For instance, Lipp et al [LWW08] enable the visual editing of shape grammar rules for modifying building appearance; Milliez et al [MWCS13] allow the mutation and duplication of object parts for structured shapes pre-defined using puzzle-grammars; Jordao et al [JPCC14] extend the previous method to crowd-patches embedding recomputed crowd animation data; Emilien et al [EPCV15] maintain the consistency of a waterfall scene under vector-based design; Longay et al [LRBP12] allow us to manipulate a realistic tree through sketching and Stanculescuet al [SCCS13] extend quasiuniform meshes [SCC11] for accounting for feature lines, using a taxonomy of possible behaviours.…”