Computational Fluid Dynamics in Computer Graphics - Page 1

Fluids in Special Effects

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Physical Models

Film a scaled representation of the desired flow

All of those old movies with sailing ships in storms
The Posiedon Adventure
Dante's Peak - pyroclastic cloud was probably ink in a water tank; I heard that Ken Musgrave was commissioned to create a fractal cloud for the movie, but it didn't look realistic enough
Phantom Menace - used poured salt for waterfalls

Computer Rendering

The emphasis here is on rendering of fluids with non-realistic motion

The Abyss - water tentacle, tidal wave in director's cut
Magnolia - "rain" drop impacts
The Fifth Element - only the sea is CG, the clouds are a matte painting, and the ship is a model

Actual Fluid Dynamics

Physics were actually considered during the creation of some modern fluid effects

Star Trek:Voyager - intro sequence, Voyager flies through gas cloud, its only a 2D effect
Twister - make it messy enough so that no one'll notice the flow is wrong
Antz - flow around obstacles, Nick Foster's PhD thesis was on computation and rendering water flows, PDI picked him up and he helped with the fluid dynamics for Antz.
A Bug's Life - also featured nice surface tension effects, but the fire left something to be desired (as it always does)
The Perfect Storm - nice waves; ILM used massive particle systems to create these effects
Oh, yeah, Titanic - the ship's wake was computed, but notice how the bow wake and the aft wake are completely separate

Future Developments (if audiences get tired of the above effects)

In the future, CG artists and programmers will need to revise and correct their models for physical flow to satisfy the increasingly demanding and discerning moviegoer.

real turbulence - large, billowing shapes like clouds
separated flow around obstacles
correct (non-fuzzy) water waves
fire - don't even get me started

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Mark J. Stock, Aerospace Engineering, The University of Michigan