“A Practical Guide to Thin Film and Drips Simulation”

  • ©Alexey Stomakhin, Andrew Moffat, and Gary Boyle

  • ©Alexey Stomakhin, Andrew Moffat, and Gary Boyle

  • ©Alexey Stomakhin, Andrew Moffat, and Gary Boyle



Entry Number: 72


    A Practical Guide to Thin Film and Drips Simulation



    We present a practical approach to model close-up water interaction with characters. We specifically focus on high-fidelity surface tension and adhesion effects as water sheds off skin. We show that an existing particle-in-cell (FLIP/APIC) solver can be adapted to capture small-scale water-solid interaction dynamics and discuss the role and implementation details of the relevant key components: treatment of surface tension and viscosity, enforcement of contact angle, and maintenance of contact with fast-moving collision geometry. The method allows for resolution of effects on a scale of a fraction of a millimeter and is performant enough to be able to cover a whole human body with a layer of water. We demonstrate successful use of the approach in a shot from Alita: Battle Angel.


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    We would like to thank simulation, FX and leadership of Weta Digital for their support with the submission, and also Lightstorm Entertainment and Twentieth Century Fox Film Corporation for their permission to use the character model and the shot from Alita: Battle Angel.


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