I interesting about Parametric quintic spline(Parametric -> chord length).
This equation Reference Data is ...
http://books.google.com/books?id=kYG17apHcrYC&pg=PA1&dq=%22Computer+Aided+Geometric+Design%22&ei=woL-RoujEJ3qpwLyw_jsBQ&sig=z19_EIHAvEi9bLZ6lC7s1mdtg3I#PPA92,M2
But this...