Parameterised free-form feature templates

Even if today's CAD systems can easily represent free-form shapes by means of NURBS surfaces, their definition and modification still require a deep knowledge and a great skill in the manipulation of the underlying mathematical models. This paper presents an attempt to bring the feature concepts, well-known in the classical mechanical domain, to the free-form domain. The paper extends our previous work on fully free-form features to include parameterised feature templates. The free-form shapes are obtained by deformation according to specific constraint lines taking part to the feature templates definition. The feature template is adapted to the user-specified parameter values by our deformation engine, which can applied either to surfaces and curves. The method is illustrated with examples obtained with our prototype software.