Modélisation tridimensionnelle

La modélisation tridimensionnelle est l'étape en infographie tridimensionnelle qui consiste à créer, dans un logiciel de modélisation 3D, un objet en trois dimensions, par ajout, soustraction et modifications de ses constituants. La révolution consiste à faire tourner un profil 2D autour d'un axe 3D : on obtient ainsi un volume de révolution. C'est la technique majoritairement utilisée dans le jeu vidéo, et le cinéma d'animation. La modélisation polygonale induit une marge d'erreur de proportions et de dimensions le plus souvent invisible à l'œil nu. Dans le cinéma d'animation, les modèles 3D organiques sont le plus souvent lissés. Le lissage consiste à subdiviser un maillage (une itération correspond à une subdivision de chaque arête, soit dans le cas de face à quatre côtés, une subdivision en quatre faces) et arrondir les faces obtenues selon différents algorithmes, afin de gommer l'effet anguleux des modèles obtenus par modélisation polygonale. Modélisation à partir d'exempl

Simulated heat storage in Canada's most northern lake: Towards a 3 dimensional model

Nicolas Bochaton

This work focuses on heat fluxes and hydrodynamic of Ward Hunt Lake, Canada's most northern lake, as well as its response to climate variations. The project aims to implement a heat budget model, in order to improve our understanding of underlying mechanisms (water column stability, heat advection from waterflows during melting periods, influence of net solar radiation and air temperature variations, feedback effects). The first step is to build a unidimensionnal model, based on tne model from Vincent et al. (2008) implemented for the perennial-ice-covered Lake A, very close to Ward Hunt Lake. Then the model will be extended to two dimensions, along a vertical transect. Finally, the feasibility of extending it to a 3D model will be explored, in order to determine the entire data needed to do so. The project will be completed by a field campaign on Ward Hunt Island and northern Ellesmere Island, in the Canadian High Arctic, during 3 weeks in July 2017.

2017

Vague de surf en bassin

Cédric Maxime Egolf

A design of a wave pool for surfing is defined in this work. The geometry is designed in order to optimize the relatively small area available for the project. The bathymetry is suited to the different levels of surfers. A wave generation system composed of aligned plungers is selected in view of minimizing energy consumption and not infringing the patents registered. A 3D model on the CFD software Flow-3D is produced in accordance with the theory to confirm the results obtained. A lateral energy dispersion effect is observed which leads to a non-uniform generated wave height. An estimate of the energy efficiency and cost per wave is calculated, and a study of the main environmental impacts is made.

2020

On the modelling and regulation of the cardiovascular system: Applications in 1D & 3D

Gaëlle Diserens

Baroreceptors are sensory cells that help the body to keep a constant aortic pressure by regulating cardiovascular parameters. The cardiovascular system can be modelled by several methods, comprising lumped parameter models which represent important parts of the body, or 3D models which are used to observe the local flow and pressure distribution. Current state of the art of modelling couples these models together in order to get more accurate 3D solutions in a computationally tractable manner. In the first part of this work, baroreflexes have been modelled using fuzzy controllers and inserted in a lumped parameter cardiovascular loop. Simulation results have shown the control of the system: The aortic pressure coming back to normal values after a slight perturbation imposed to the model, as long as this perturbation is within a physiological range. For strong perturbations, a limit of the baroreceptors was reached, corresponding to the natural regulation limit of the body. The second part of this work was to study the influence of boundary conditions imposed on the 3D models, with the final aim to couple the lumped parameter cardiovascular loop with a 3D model. Results showed different velocity and pressures distributions according to different boundary conditions. The most important result was the coupling of a 3D vessel with a cardiovascular loop, where several heart cycles were simulated: pressures and flows curves were stable over the different heart cycles. Barocontrollers were then inserted in this coupling, and showed the possibility to control the system if the initial pressure is higher than normal. Pressure regulation of a 1D-3D coupling model has been made. Next step could consist of replacing the straight pipe by the aortic arch, with some adjustments to the lumped parameter model. Moreover, an alternative 3D part of the cardiovascular loop, such as a valve, could be inserted in the system

2010

On the modelling and regulation of the cardiovascular system: Applications in 1D & 3D

Gaëlle Diserens

2010