Chen Shen, Apurva Shah
From pouring sauces to sudsy sink water to violent sewer rapids, realistic animation of fluids presented interesting challenges in Ratatouille. The various fluid effects were simulated either using a physically-based solver or directly with generic particle systems.
Although the simulated particles move as a whole like a fluid, the number of particles was too small to give the appearance of a continuous
surface if rendered directly. To address this, we developed a technique to efficiently extract temporally and spatially coherent surfaces from particles with parametrization that allows textural details to be later added in rendering.
Available as Pixar Technical Memo #07-05