Représentation, modélisation et génération procédurale de terrains

Slides disponiblesSoutenance oral (présentation + questions) disponible sur demandeThis PhD (entitled "Representation, modelisation and procedural generation of terrains") is related to movie and videogames digital content creation, especially natural scenes.Our work is dedicated to handle and to generate landscapes efficently. We propose a new model based on a construction tree inside which the user can handle parts of the terrain intuitively. We also present techniques to efficently visualize such model. Finally, we present a new algorithm for generating large-scale terrains exhibiting hierarchical structures based on their hydrographic networks: elevation is generated in a broad compliance to water-tansport principles without having to resort on costly hydraulic simulations.Cette thèse (qui a pour intitulé "Représentation, modélisation et génération procédurale de terrains") a pour cadre la génération de contenus numériques destinés aux films et aux jeux-vidéos, en particulier les scènes naturelles.Nos travaux visent à représenter et à générer des terrains. Nous proposons, en particulier, un nouveau modèle de représentation qui s'appuie sur un arbre de construction et qui va permettre à l'utilisateur de manipuler des morceaux de terrain de façon intuitive. Nous présentons également des techniques pour visualiser ce modèle avec un maximum d'efficacité. Enfin nous développons un nouvel algorithme de génération de terrains qui construit de très grands reliefs possédant des structures hiérarchiques découlant d'un réseau hydrographique : le relief généré est conforme aux grands principes d'écoulement des eaux sans avoir besoin d'utiliser de coûteuses simulations d'érosion hydrique

Landscape Specification Resizing

International audienceIn this work, we introduce a method for resizinga landscape specification, i.e., a vector model containing a set ofobjects present in a virtual environment. Our goal is to changethe landscape dimensions while keeping its overall appearance.Our method is based on the insertion and removal of objectsin the specification, followed by some adjustments of the sceneadapting the initial model to these changes. Besides the proposedapproach for the positioning the objects, this method can be easilyextended to use techniques of the state of the art for spreadingobjects in the landscape.The adjustment of the scene components consists in performing vertical or horizontal translations onto the position of theobjects. It is based on a removal or insertion of paths in thegrid created over the scene space using dynamic programming.In spite of dealing with a vector model, all proposed operationsare performed in the pixel space.This technique is an adaptation of the Seam Carving for thecontext of vector landscapes specification. This model is simplerthan common images, and thus, we can achieve results as goodas those obtained in the image context, using simpler metrics