Modelling Hair Collisions Using Spline-Based Cylinder Chains

This paper discusses a method of modelling collisions between long hairs. The hairs are modelled as cubic B-splines, to which chains of cylinders are fitted for the purposes of collision detection. The head on which the hairs rest is modelled as an ellipsoid. The paper explains how to fit cylinder chains to splines, how to test whether and where two cylinder chains intersect, and how to test whether and where a cylinder chain intersects an ellipsoid. It further shows how to make use of these results to model (a necessarily limited amount of) long hair on a human head.