Mathematical modelling and computer animation Animation of chocolate

Mathematical modelling and computer animation Animation of chocolate flow on complex surface Martin Madaras

Intro �Fountain �Real model flow �Flow simulation �Fluid mesh �Rendering

Fountain model 3 D Studio Max � Low-res for simulation, High-res for rendering �

Real flow � Next Limit, authors of renderer Maxwell (using metropolis light transport algorithm for global illuminance computation), more correct than other renderers � Disadvantages : Very long rendering time, preview can be made at the moment, but is very noisy � XFlow and Real. Flow, Real. Flow is used in entertainment industry, XFlow in science and technology � Real. Flow is standalone app, for simulation only (fluid, gas, rigid bodies) � Rendering must be made in other programs 3 DS Max, Blender, . . .

Fluid mesh

Flow simulation 1 � World in program Real. Flow is simuluted with Deamons, which affect behavior of material (gravitation, noisefield, vortex…) � There also Kill Deamons, which can delete particles when they satisfy some conditions (particles are out of camera frustrum, velocity is too high, particle has no neighbours in some range) � Geometry can be imported, all faces should be triangles (for better computation) � Chocolate has high viscosity and surface tension, these parameters affect time of computation (number of particles had to be lowered) � CPU : 4 core q 6600, time necessary for simulation of 1100 frames was 11 hours

Flow simulation 2 � 2 phases of simulation. In first is simulation made on particles (number based on emiter settings) � In second, mesh is created over particles ( Blob Meshes) � Afterwards, mesh can be exported for every frame and imported into another program via plugin. Mesh behaves as normal object � Flow simulation computation is very expensive

Import via next limit plugin

Lighting and camera � Camera path is ellipsoid spiral spline � Rendered with VRay render, Indirect illumination calcualtion � Lighting made via HDRI map of interior

Rendering and postprocessing � Fountain model was surrouned by cylinder panoramatic photo of chocolate shop. Panoramatic photo was blured for better look � Frames joined in open source software Virtual dub and exported into avi, coded with H. 264 divx codec

Images