Feature oriented composition of B-Spline surfaces

Abstract

Detailed features are added to composite spline surfaces in a multi-layered fashion by means of an efficient displacement scheme. The feature orientation is arbitrary, and the underlying domains may be partially overlapping and non-linearly transformed. By mapping only the control vertices, defined as displacement vectors in a diffuse co-ordinate system, we can manipulate the pasted elements in real-time, independently or as a whole.

The procedure, known as pasting, is more than a refinement instrument. It makes possible the rendering of a surface composition selectively, and this expedites the rendering process. It can be used to model surfaces by interactively changing displacement, control vertices, or the domain layout. Base surfaces may serve as sliding paths for pasted clusters whose shape and motion are determined by the underlying topography, resulting in an organic motion effect. Pasting also applies to higher-dimension entities, which may incorporate non-geometric components, such as colour, opacity or brightness.