Expert form feature modelling shell

Contemporary geometric modellers are unsuitable for mechanical design because of mismatch in abstraction level. The databases of these modellers cannot be used to drive automated applications such as engineering analysis or process planning because of missing product information. The paper outlines an integrated system for design and applications; the system reasons in terms of form features. Object-oriented programming techniques support user definition of form features (volumetric shapes) that may be positioned and manipulated in a logical manner. A solid modeller interface generates equivalent solid representations in parallel with feature representations. Mechanisms for parameter inheritance and validity checking (cognition) are also discussed. The system is modular, which will allow it to be integrated with tolerance and material modellers that are currently under development. Artificial intelligence techniques have been applied to solid modelling, resulting in this powerful feature technology for creating flexible and integrated CAD systems for the next generation of engineering tools.