The topic known as computer-aided design and manufacture has developed rapidly over the last 20 years. The range of hardware configurations and supporting software on offer to the potential user is bewildering. This extends from the inexpensive single-user micro-based system, through to the vast industrial networks which are supported by many remote mainframe machines and have been reported to service up to a thousand workstations. This advance in technology has been driven by, and in its turn has fuelled, the development of ever greater computing power and graphics capability. It is these features that all working in the field would now recognize as essential to any