However, in [Koh00], animation is achieved by keyframing of the control points of hair strips. It is very difficult
to create motion sequences with naturally-looking and Physically-plausible movement. In this paper, we present
a simple Physics model to the strip-based hair model. In particular, a simple dynamic model is adapted and
applied to the control point meshes. A set of dynamics equations are defined and solved for the control points.
The parametric representation of hair strips can handle a deformation of any complexity and still appear smooth.
Moreover, because the number of control points is much smaller than the tessellated triangles, the computation
is fast to achieve real time animation. The animation of hair is controlled using event-triggered procedural
animation primitives that implement wind, gravity as well as head motion. Inter hair strip collision avoidance is
achieved by introducing springs between neighboring hair strips. Collision avoidance of hair and other objects
are implemented using ellipsoids and reaction constraints.