Aspects of realizing the CFI design representation specification in the NELSIS framework

The CFI (CAD Framework initiative) organization aims to provide solutions for concurrent engineering by defining a set of standard textual specifications for interfaces that should enable ECAD tool consumers to incorporate tools from various vendors. The most mature of these specifications is the DRPI, a programming interface which specifies the data schema and functions for manipulating elementary ECAD objects. The authors' objective was to implement the DRPI specification utilizing the NELSIS CAD framework. NELSIS supports a large grained schema; there is just one entity type (called the design object) for representing the design data. Additional entities in the schema provide relational information about the design object. In contrast, the DRPI data schema is fine grained; all data are represented explicitly and homogeneously by many entities. To bridge the gap, an object manager is required. The authors have coupled DRPI to NELSIS in two different ways. The first uses a custom-built dedicated object manager implemented in C, and the second uses a general purpose object oriented manager implemented in C++. The focus is on the schema mapping. The authors provide suggestions for enhancing the CFI schema, and highlight the problems and solutions of performing the mapping. They conclude with several open questions and recommendations.<>