Pixar

Olivier Soares

Mark Joseph Meyer

Lena Petrovic

Hayley Iben

Techniques are disclosed for stably simulating stylized curly hair that address artistic needs and performance demands, both found in the production of feature films. To satisfy the artistic requirement of maintaining a curl's helical shape during motion, a hair model is developed based upon an extensible elastic rod. A method is provided for stably computing a frame along a hair curve for stable simulation of curly hair. The hair model introduces a new type of spring for controlling the bending and twisting of a curl and another for maintaining the helical shape during extension. The disclosed techniques address performance concerns often associated with handling hair-hair contact interactions by efficiently parallelizing the simulation. A novel algorithm is presented for pruning both hair-hair contact pairs and hair particles. The method can be used on a full length feature film and has proven to be robust and stable over a wide range of animated motion and on a variety of hair styles, from straight to wavy to curly.

Artistic simulation of curly hair

Computer-generated images based on force field effects are generated by evaluating force field data and animated data. The force field data includes force field directional vectors and the animated data includes density values for an animated model. The force field data and the animated data are splattered on separate multi-dimensional grids. An animation system determines a vector path, starting at a point in the grid containing the animated model, based on the directional vectors and the density values along the vector path are integrated to determine an attenuation factor for the point. The attenuation factor provides a value for accurately determining the movement of the animated model at the point when the force field is present.

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Emeryville, CA, United States of America

Olivier Soares