Delicious, Thirst Quenching Fluid Simulation

1- Computer processing improves.

Take the movie Big Hero 6 for example: "To put the enormity of this computational effort into perspective, Hendrickson says that Hyperion "could render Tangled from scratch every 10 days."

The better the computer gets at processing complexities, the more time the artists can focus on improving the physics. As you can see, with Big Hero, they had the ambition and the know how in terms of wanting to improve the lighting in the movie, but they just lacked feasible processing times. This is why they built a whole new computer to handle it all.

2- PHDs, physicists, and all sorts of scientists contribute: They hire people to develop the mathematical formulas that help create the programs they use. Of course formulas can be limited, so artists can tweak specific areas to make them look more realistic.

It really is a unity between these two because they seem to always play catch-up with each other. One may have an understanding of the physics behind a certain element, but the computers may just not be able to handle those computations in reasonable time so they just don't pursue it.

You'll notice that with each and every major pixar movie that comes out, they always push a new technology: with Finding Nemo they wanted to finally try to work with water, "Pixar invited a scientist to present lectures on waves, swells and other motions. Several staff members took a trip to Hawaii in 2000 to study water and sea life. They ended up using reference footage from that trip to describe conditions above and below the surface. Jacob recalled conversations at work such as: "Remember what it was like on the boat on Thursday afternoon? I want the water like that. Or: "Do you want it to look more like Wednesday or Friday? They found that referring back to those experiences was more useful than saying, I want it more choppy than angry.""

With tangled, they emphasized hair.

With Big Hero 6 they emphasized complex lighting.

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