A detailed model of the 3D strand of curly hair that could be a boon for the computer and film animation industries has now be developed.
Previously, scientists had no way to describe the motion of curly hair, including the way curls bounce as they move around.
Researchers at Massachusetts Institute of Technology (MIT) and the Université Pierre-et-Marie-Curie (UPMC) in Paris are unraveling the physics of curly hair.
"Our work does not deal with the collisions of all the hairs on a head, which is a very important effect for animators to control a hairstyle," said Pedro Reis, an assistant professor at MIT.
"But it characterises all the different degrees of curliness of a hair and describes mathematically how the properties of the curl change along the arc length of a hair."
The researchers combined their lab demonstrations with computer simulations to identify curvature, length, weight and stiffness of curly hair.
Reis and team also examined how the shape of curls changed when various parameters were altered.
If only a portion of the strand was curled, the researchers labeled the 3D structure a "localised helix".
If the entire length of the strand was curled, the researchers referred to it as a "global helix".
The model could help computer animators make curly hair look more realistic in movies.
Beyond curly hair, the model could be used to predict the curves of tubes, cables or the types of steel pipes used in the oil industry, the researchers said.
The findings were published in the journal Physical Review Letters.