Curly Hair Algothrithm

Hair has always been difficult and expensive to render in computer animation. It requires numerous strands that move harmoniously with each other, while reacting realistically to characters' movements and the surrounding environment. To minimize cost and complications, short, straight hair is preferred, and is typically rendered by keyhairs that interpolate the strands between keyhairs to create a sheet of hair that moves as one mass. Alternative methods do exist, but often have complications of their own, as with Rosenblum's [citation needed] method of rendering hair as single strand mass-spring models, which is useful for single strands but proves too expensive to compute hair-to-hair contact.

With their newest movie, Brave, Pixar has created a new method similar to Rosenblum's that renders hair as a mass-spring system while keeping hair-hair contact costs low. Moreover, this method can and was applied to various types of hair in Brave, from Merida's long, curly locks to Angus' sleek mane and tail. Hair rendering methods that can handle such a broad range of hairstyles and maintain a reasonable rendering cost are uncommonly efficient, and warrant further analysis that this presentation [paper?] will provide.