Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


2008 Research Summary

Fluid Animation with Dynamic Meshes

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Nuttapong Chentanez, Bryan Eric Feldman, Bryan Matthew Klingner and James O'Brien

Our project developed a method for animating fluid with unstructured tetrahedral meshes that change at each time step. Meshes that conform well to changing boundaries and that focus computation in the visually important parts of the domain can be generated quickly and reliably using existing techniques. We also developed a new approach to two-way coupling of fluid and rigid bodies that, while general, benefits from remeshing. Overall, the method provides a flexible environment for creating complex scenes involving fluid animation.

Figure 1
Figure 1: Top: a paddle mixes smoke in a tank. Bottom: a cross-section of the simulation meshes used for each frame.

Figure 2
Figure 2: A comparison between uniform and selectively refined simulation meshes. Left: a frame from a simulation using approximately 43000 uniformly sized tetrahedra. Right: the same frame using approximately 32000 tetrahedra refined near areas of high vorticity and smoke density. The refined mesh preserves the fine detail in the velocity field and near the visible smoke, enhancing vortex action and natural movement. The runtimes of the two are equivalent.

Figure 3
Figure 3: Left: a visualization of the sizing field for a rectangular domain with an irregular obstacle at the top and a plume of smoke at the bottom. Right: the resulting simulation mesh. Obstacle faces are colored green.

Figure 4
Figure 4: Red particles are transfered from the left tank to the right by squeezing and releasing the central bulb. The blue valves are coupled to the fluid simulation and prevent backflow.

B. Feldman, J. F. O'Brien, and B. M. Klingner, "Animating Gases with Hybrid Meshes," Proc. ACM SIGGRAPH, 2005.
B. Feldman, J. F. O'Brien, B. M. Klingner, and T. Goktekin, "Fluids in Deforming Meshes," ACM SIGGRAPH/Eurographics Symp. Computer Animation, 2005.