Abstract: A control mesh of polygonal approximations is generated from one of a variety of conventional object representation schemes. The control mesh is a uniform representation of the object to be rendered comprising edge information and reconstruction data for the polygons comprising the control mesh. Reconstruction data includes surface normal data, and surface hint data. Surface hint data includes information regarding whether a vertex is a sharp point, or whether an edge should be represented as a hard edge. Resolution levels are calculated for all of the vertices of all of the polygons in the control mesh. Resolution levels specify the appropriate level of resolution for a triangle or other polygon responsive to the topology of the object and the camera angle currently being used in the application. Responsive to calculating the resolution levels, the polygons are subdivided responsive to the resolution levels.

Abstract: For simultaneous deformations of multiple surfaces, a constraint called a link constraint is created to link two faces that are to be deformed together. The link constraint consists of a relationship between a constraint curve in each face to be deformed. The selected constraint curve may be any curve, including trimmed curves and part of a boundary curve. As the faces are deformed, the link constraint limits the deformation of the faces by acting as a zipper between the two surfaces along the selected constraint curve. For local deformations within a surface, a hierarchy is created within specific areas, known as patches, of an individual face in a model, ensuring that when a patch in the hierarchy is deformed, the deformation affects patches lower in the hierarchy than that patch, but the deformation does not affect patches higher in the hierarchy.