
500 CHAPTER IO Subdivision Surfaces
Some common subdivision schemes include Loop, ~/3, Modified Butterfly,
Doo-Sabin, and Catmull-Clark. Maya's subdivision scheme is a hierarchical imple-
mentation of the Catmull-Clark subdivision scheme. This scheme is polygon based
and after the first subdivision generates only four-sided polygons
(quads),
though
not all vertices have valence 4. More precisely, when the control mesh is first sub-
divided each face will produce as many child faces as it has edges. As such, a four-
sided polygon will produce four child polygons. These child polygons will be
quadrilaterials. ...