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Modelowanie zjawiska wzbitego puchu śnieżnego dla potrzeb animacji komputerowej

Raczkowski J., Sobiecki M.

Pomiary Automatyka Kontrola

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2014

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R. 60, nr 5

292--296

PL

W pracy zaproponowano metodę tworzenia symulatora przepływu płynu i wykorzystania utworzonego modelu do realistycznej wizualizacji wzbijanego puchu śnieżnego. Symulator bazuje na uproszczonym i stabilnym rozwiązaniu równań Naviera-Stokesa w przestrzeni wokselowej. Przedstawiony został wpływ poszczególnych składników równań (adwekcja, dyfuzja, wpływ sił zewnętrznych i ciśnienia) na uzyskiwany rozkład gęstości płynu. W pracy opisano przykładowe animacje i przedstawiono analizę wydajności rozwiązania.

EN

Computer animation combines art and engineering in order to create artificial but realistic images. It is widely used in movie industry, advertisement, and in all areas where visual imaging is applied. Modeling natural phenomena including fluid flows is an important part of this task.In our paper we propose a method of simulation and rendering of fluid to get realistic images of selected natural phenomena. We concentrate on an animation of powder snow and pretend to produce video sequences of entrained snow by a skier or a snowboarder, snow making devices, and snow blown off from a roof. The model of snow movement is based on Navier-Stokes equations solved in an unconditionally stable way in the voxel space. All factors effecting fluid movement, including advection, external forces, diffusion and pressure impact, are considered. We propose the method for calculations of these factors assuming a number of simplifications in our solver. The volume ray-tracer from the Blender 3D open-source visualization environment is applied to render subsequent frames. As a result we present examples of created animations showing the behavior of entrained snow. This is to prove that our solver can produce accepted visual reality of the considered phenomenon. We analyze the efficiency of the proposed modeling method concluding that some factors may significantly reduce the computing power and memory requirements.

2

Interactive Hydraulic Erosion Using CUDA

Bezin R., Peyrat A., Crespin B., Terraz O., Skapin X., Meseure P.

Machine Graphics and Vision

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2011

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Vol. 20, No. 2

157-172

EN

This paper presents a method to simulate in real-time hydraulic erosion and sedimentation on a 3D soil represented by a triangular mesh. Applications include user-assisted terrain generation for computer-generated films and reverse engineering for geology. Our method achieves interactive performances by dynamically displacing vertices using CUDA and following physically-inspired principles to simulate realistic water streams and their interaction with soil and sediments. The mesh is generated in a preprocessing step to avoid degenerate cases in highly deformed areas. We present various results where landforms are progressively eroded to create visually plausible river beds.

3

A Particle-Based Method for Large-Scale Breaking Wave Simulation

Darles E., Crespin B., Ghazanfarpour D.

Machine Graphics and Vision

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2011

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Vol. 20, No. 1

3-25

EN

In this paper we address the problem of particle-based simulation of breaking waves. We present a new set of equations based on oceanographic research which allow us to deal with several types of breaking waves and multiple wave trains with full control over the governing parameters. Sprays are generated by explicitly computing sub-particle systems depending on the local motion caused by plunging. In order to reduce computations in non-significant areas, we also describe a simple and efficient multiresolution scheme based on the properties of our breaking wave model.