Title: Phenomenological Simulation of Brooks
1Phenomenological Simulation of Brooks
- Fabrice Neyret Nathalie Praizelin
- iMAGIS / GRAVIR - IMAG
iMAGIS is a joint project of CNRS, INRIA,
INPG and UJF.
http//www-imagis.imag.fr/
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4If CFD had to be used
(Navier-Stokes)
FM96,97,...
- Very thin resolution, large domain ( and
stability ? very small dt ) - Very non-linear equations (shockwaves, surf.
tension) - ? Hard and long system solving
- Unknown parameters (e.g. boundary conditions)
- Visible features are emerging phenomena ?
Hard to control - while
- Water motion is not directly visible
- Strong a priori knowledge on the result
- Users want some control
5If surface wave simulation had to be used
FR86,P86,GS97
- Very thin resolution, large domain
- Very non-linear equations (waves trigger waves)
- Hard and long system solving
- while
- Strong a priori knowledge on the result
6If Fourier synthesis had to be used
MWM87,TDG00,Areté
- Very thin resolution, large domain
- Non-linear phenomena
- Non uniform wave propagation(variable depth,
obstacles) - ? Statistical models are helpless
- while
- Strong a priori knowledge on the result
- Users want some control
7Relying on phenomenological simulation
- Primitives based
- Geometric construction of visual features
- Choice of the primitives of visual interest
- User can control the primitives
- Vector primitives independent from
rendering resolution - Fast, high resolution, large domain
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9- Phenomena that are out of scope
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11 12Wave theory
13Wave theory
capillary waves cg gt cw
shallow water cg cw
gravity waves cg lt cw
14Typology of stationary waves
non dispersive case cg cw c ? shockwave
15Froude waves - shockwaves calculation
(Froude number)
(slope)
16Froude waves - shockwaves calculation
17The chosen primitives
18Our approach
- 1. Get a stationary velocity field (low res is
ok) - 2. Build the primitives skeletons
- 3. Add field perturbations WH91
- 4. ( Build a surface and render )
191. Get a stationary velocity field
201. Get a stationary velocity field
211. Get a stationary velocity field
221. Get a stationary velocity field
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242. Build the primitives skeletons
252. Build the primitives skeletons
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273. Add field perturbations
- WH91
- Small support fields (vortex,source)attached on
particles (passive floaters)
283. Add field perturbations
- A perturbation needs time to propagate
- We cannot simply apply the static construction !
- A node moves if
- V changes locally
- the previous node has moved
perturb V gtgt
293. Add field perturbations
30Conclusion - limitations - future work
- A real-time simulation of (some) animated visual
features of brooks ! - Vectorial construction (no grid sampling)
- Perturbations can be random, procedural (von
Karman),or user generated. - Fade and stop the primitives.
- Adaptive capillary ripples.
- Define a rendering method ! (producing a surface
?) - Hydraulic jumps, foam, ...
31Phenomenological Simulation of Brooks
- Fabrice Neyret Nathalie Praizelin
- iMAGIS / GRAVIR - IMAG
iMAGIS is a joint project of CNRS, INRIA,
INPG and UJF.
http//www-imagis.imag.fr/
32- Le détail des mouvements est complexe
33Exploite-t-on toute la connaissance disponible ?
- Il y a de grandes régularités dans les scènes
naturelles !