Method for generating hair using textured fuzzy segments in a computer graphics system

DETAILED DESCRIPTION The present invention is divided into two parts: simulation and rendering.
A simulator calculates the motion dynamics of a hair.
The simulator includes a particle system that emits particles from a surface over time and a normalization module that normalizes the trajectory of each of the particles to a fixed length.
The renderer performs a variety of tasks, including fuzzy segment generation and self-shadowing, that results in an image being displayed on a display device.
That is, the renderer takes three-dimensional spacial information, applies a light to this information and renders this information as a two-dimensional image.
In a preferred embodiment, a plurality of particles having a mass and a non-zero velocity are emitted from a surface over a period of time.
Each timestep a particle is emitted from the same position on the surface.
During each timestep, the trajectory of each particle is normalized to produce a set of normalized segments.
The normalized segments are joined to simulate a hair.
Consequently, particles at the root of a hair are emitted a few timesteps before the particles at the tip of the hair are emitted.
That is, the tip of a hair lags behind the root of a hair.
This phenomenon has been termed "lag animation.
" The hair is further shaped by placing it within a force field.
During rendering, the appearance and motion of a hair is modeled by creating a fuzzy segment around each normalized segment.
Each consecutive pair of fuzzy segments define a single hair segment.
Each fuzzy segment is assigned a density.
A texture map is applied to each fuzzy segment to allow a user to create a desired hair style or fur-pattern.
The present invention allows a user to view complex simulations of hair in real-time on a graphics work station.