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Current time:0:00Total duration:1:58

(bouncing) - In the last video, we saw this preview of a shot from Finding Nemo where we've drawn the particles as balls to illustrate their motion. For the final shot, we
used the particle positions to compute a surface. Then we rendered that surface
to look more like water. To draw a smooth surface
using individual particles, we use an analogy involving heat. First, imagine these
particles are little heaters. Next, pretend we have a thermometer which tells us the temperature
at any point in space. For example, the particles
might be exactly 1,000 degrees, and as we move away, things cooled down. Let's say this point over
here is exactly 100 degrees, and there isn't just one point in space which is 100 degrees, but many points. So if we connect all points
where the thermometer says 100 degrees, we get a
curve shown here in yellow. And that's the trick. Now we can fill in this yellow
curve with a solid blue color to give us something that looks
more like a puddle of water. If the particles are far apart, they each form their own
isolated region, like a droplet. As they get closer, the
droplets start to glob together, mimicking real water. Here's a version with
a few more particles. This is starting to look like water. It would really look like water if we had a few thousand particles. For use in our movies, we
work in three dimensions, and the curve becomes a surface like in this shot from Finding Dory, or in this more extreme water simulation also from Finding Dory. Here's an example from
Monsters University. Here we're simulating
paint, instead of water. We've turned up the viscosity since paint is more viscous than water. We weren't exactly sure
how paint would behave so one of the first things
we did to create this shot is to videotape reference of real paint. The reference really helped
us create a believable look. Let's pause here so you can practice using the next exercise. Good luck. (playful music)