◾ Fluids on Arbitrary Surfaces
Previously, we talked about uids on donuts, also known as tori, which we harnessed using the almighty Fourier transform. Now I will briey describe a technique to animate uids on other surfaces: surfaces with more holes or less than donuts. A good example is our good old earth, which is topologically equivalent to a sphere: a big blue round ball with some uy clouds oating on it. No holes. But there are surfaces with more holes. Some of those creatures are depicted in Figure 13.1. e creature on the far right is not even a closed surface, but it is has one hole.