Liquid Simulation Series: Mountain Dew part 2

After mastering the main flow of the dam, the team was ready to attack all of the splashing elements that characterize the turbulent flow of the surging water.  The crux of the simulation, these splash elements were actually comprised of several separate fluid simulations that, when brought together, would create the overall effect of crashing water.

various splash simulations and the script used to strip out excess particle

As was mentioned in the previous post, the final simulations had to run at an extreme resolution in order to ensure that there was enough detail within the splashes to create a realistic look to the flow.  However, it was impossible to work at this level of detail and then actually render within the 3D authoring tool.  To navigate this issue, the team wrote a bespoke script that would strip out the extraneous particles from the simulation while maintaining an aesthetically workable resolution [see image above].  In addition, they did a tremendous amount of R&D work to push the limits of the system to determine how high they could set the particle count and still finish simulating on schedule.   As such, they were able to create a simulation with a fairly high level of detail in the splashes. The three images below illustrate the level of detail visible at increasingly zoomed in distances.  These images were taken of the particle clouds after the script had been run.  Click on the images for a larger view.

zoomed out

zooming in closer

zooming closer still

Looking at the clip above, each colored box represents an independent splash.  These splashes were created by the curvature and density of the primary fluid simulation down the dam. Particles were emitted wherever details in the waviness or density of the main flow met specific criteria. In this case above, when the threshold for the density fell below a certain level, splashes occurred. In other words, the edges of the water happened where it met the geometry of the dam. 

splash simulations looking down the dam:  each colored box represents an independent splash

splash simulations:  alternative view of the various splashes interacting down the dam

Because each splash was composed of several fluid simulations, the next challenge was usurping enough machine power to actually complete each simulation.  Working in Next Limit’s RealFlow, the software’s IDOC (Independent Domain of Computation) system was a incredible help as it allowed the team to complete different elements of each splash simulation across multiple machines, thus allowing the team to have more time to research, develop and perfect the piece and also allowing them to complete the work on schedule.

As mentioned before, it took an incredible amount of R&D to perfect the fluid simulations.  Check back tomorrow to see a few of the ill-fated attempts that eventually led the CG team to their completed work.