Action disabled: export_raw
non-uniform national b-splines
Chapter 13. Evaluators and NURBS > http://www.parallab.uib.no/SGI_bookshelves/SGI_Developer/books/OpenGL_PG/sgi_html/ch13.html#id5524141
Chapter 13. Evaluators and NURBS > http://www.parallab.uib.no/SGI_bookshelves/SGI_Developer/books/OpenGL_PG/sgi_html/ch13.html#id5524141