The OpenSubdiv feature set lets modelers use controlled subdivision to create shapes with smooth and creased surfaces based on polygonal objects. You can specify the overall curvature of the surface, and base variable creasing on vertices and edges in the polygon mesh.
OpenSubdiv uses advanced software technology from Pixar for modeling and animating subdivision surfaces on massively parallel CPU and GPU architectures. For technical background information, see http://graphics.pixar.com/opensubdiv/
The OpenSubdiv implementation in 3ds Max comprises two modifiers: OpenSubdiv and CreaseSet. OpenSubdiv performs the subdivision, smoothing, and creasing, while CreaseSet provides enhanced features for specifying and managing sets of vertices and edges as well as their Crease settings. CreaseSet also features the Crease Explorer for managing creased sub-objects with a spreadsheet-style interface.