A Semantic Blend Feature Definition

In most current feature modelling systems, blends are modelled as a kind of features too. These systems use a boundary representation (Brep) to describe the shape of a product. It is shown that the practice of basing specification of blends on conventional Breps is ineffective. A solution to this problem is introduced in which blends are described at a higher level. Blends are defined in a feature class, and instances of such a class can be added to a feature model containing relations between all features in the model. Such a semantic description of blends has several merits. In particular, constraints can be defined on them to specify important functional properties, and these properties can be maintained during the whole modelling process through validity maintenance. A new method to determine the shape of a blend, based on its properties, is also demonstrated.