A CAD data structure to facilitate change

Amongst the established advantages of CAD is the ease of making changes. However, making one change usually has further implications but most existing systems are unable to assist with these changes unless an explicit link is established during the development of the design. This paper identifies different classes of change and proposes a data structure which incorporates relational operators to capture the relationships between the model components. These spatial relationships are acquired directly as the model is constructed and are used to identify the implications of a change and to suggest a possible implementation of them, based on design intent.