For rendering, we tessellate the NURBS representation into polygon mesh. The Oslo algorithm is implemented
using the multiple knot insertion for the tessellation [Cohe80, Meye91]. If more than a few knots are being
inserted at once, the Oslo algorithm is more efficient than the Böhm algorithm [Böhm80]. Finally, texture maps
of hair images can be applied on either one or both sides of each surface patch. The alpha map defines
transparency and creates an illusion of complex geometry to the otherwise "rectangular" surfaces and adds to the
final realism (Fig 1a, b, c, and e).
Fig 1.