From the Introduction: Some companies represent their product family design as a space of design alternatives. The design space is a mathematical space that is governed by applying a set of design rules to design parameters. A key principle in establishing a design space instead of developing a single solution is to put minimum requirements for design optimization in the early stages of development. Developing a new design variant requires understanding the base design and adapting the design according to the new requirements. Use of design rationale can provide such understanding. With increasing the number of variants, access to design rationale becomes more important. Understanding why a design variant was accepted and if there have been any other alternatives in the beginning but were rejected (due to functionality or manufacturing limitations) can help the designers to avoid developing new design variants that have previously been proven wrong. Or it can support the designers to propose design variants that can be accepted under specific conditions for unique customers. The repetitive and time consuming design activities can be assigned to design automation systems in order to increase efficiency and shorten the lead time. The use of design automation system is more vital when the number of design variants drastically increase. Use of Domain Specific Language (DSL) can amplify the applicability of the design automation system by targeting specific domains. A DSL is a computer language that is developed focusing on a particular application domain [3] (some DSLs are widespread such as SQL which is used for database querying, but many are note widespread).

In this paper, a method is presented for capturing and sharing design rationale for each design variant in an integrated design environment. An argumentation-based approach is used for capturing design rationale. An industrial partner which has a long tradition in automating its design process has been involved in the research, and the results of the research have been tested and evaluated in the company. In total, 11 workshops, 15 meetings and more than 20 semi-structured interviews with engineers from different departments in the company were conducted. A method and prototype system were developed to enable capture and share design rationale. The prototype system was demonstrated for a group of engineers on-site and a group of designers across the globe as part of the development. DSL is used initially by the company to develop the automation system. Our proposed design rationale system was developed as an extension to the automation system.