Pixar in a Box
Discover how Pixar simulates hair motion for characters like Merida in "Brave" using physics and computer programming. Learn about simplifying complex hair models with line segments and particles, and explore the forces acting on these particles, including gravity and neighboring connections. Dive into interactive programs to adjust parameters and create unique looks.
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- So how would you factor in wind in the modeling of hair with the weight of gravity and the other hairs?(15 votes)
- This is so interesting and exciting! What pre-requisite class must I do
(physics?, math?) in order to be able to learn and play with this knowledge?(13 votes)
- Coding is a great class to take and there are online courses here! Physics is another class to take too. As for math, everyone takes math. :) technology and computers are good things to learn about as well.(9 votes)
- So along with the wind factor, how would one be able to model the hair if it was wet, or if the character was running through the rain?(4 votes)
- Hello! Animating hair when wet is a challenge. You'd need to make the hair straighter and connected and stick but you need to let the hair be able to sway. You also should make it slightly darker and shinier. Observing from life is a great way to obtain your goal of realism.(4 votes)
- Dear sal khan why are we ordered to each this what is it helping us with(2 votes)
- This gives you an understanding in what Pixar does when animating and is resourceful if you plan on taking a job like this or are just curious!(5 votes)
- How do I play that interactive program @2:01(3 votes)
- that is so cool
thanks for helping me
How do you make it so real?(2 votes)
- pixar controls multiple clumps at a time. they start off with a mesh (3d object in the vague shap of a hair clump and convert that geometry to A LOT of smaler stands with different colors and glosiness(2 votes)
- We actually do a lot of simulation at Pixar. Things like fire, water, and explosions are handled by the effects department. You can learn more about that in the effects lesson. The simulation department, who I work with, handles any motion attached to the characters at Pixar, like clothing and hair. But we can't move every hair on a Pixar character's head by hand, that would drive our animators crazy. Instead, we use Physics and Computer Programming. In this lesson, you'll learn how to simulate hair the same way we did for Merida in the movie "Brave". Here is an example of a shot of Merida that the simulation department got from the animation department on the film "Brave". The animators have created the main action in the scene and now it's our job to fill in the missing details such as the motion of cloth and hair. Everything we do begins with modeling the problem we want to solve. In this case, we need a physical model of Merida's curly hair. So let's begin with the very basics. What should our model of hair look like? Well, hair is kind of like a mop, just a bunch of strings. But strings are actually quite complex to model mathematically because they are so bendy. Modeling them requires a lot of computational power due to all the calculations involved. This is why we are always looking for ways to simplify our models. For example, we could take a bunch of paper clips to model a strand of hair. We first draw a series of line segments connected to particles, like this. The computer needs to calculate the positions of these particles. But first we need to describe what forces are acting on them. In the real world, each particle is affected by three forces. The force of gravity, and the forces from neighboring connections, like this. Next step, I have an interactive program for you to see this in action. You can adjust the following parameters: size of each segment, number of segments per hair, number of hairs, and the force of gravity. Explore these parameters to see what kinds of looks you can come up with. Have fun.