In this paper we present a user interface that supports design engineers in having efficient interaction with their CAD system. We adopt a flow-based paradigm for design history browsing and tool selection. Based on this paradigm the user interface shows design objects in the context of executed-, enabled- and disabled tools and related design objects. We present a flow coloring algorithm which is used by the user interface to automatically select convenient doses of information related to a user-specified design object. The user interface integrates many aspects of user interaction into a single platform that enables design engineers to efficiently execute the design cycle. This includes tool invocation facilities, an intuitive mechanism for interaction among different browsers, and a mechanism for automatic updates of the information that is being displayed as changes occur. The user interface has been implemented as a desktop facility in the Nelsis CAD Framework.

An attempt to realize an integrated design environment with a maximum of functionality and an absolute minimum impact on existing design tools is discussed. Addressed are the interface between the design tools and the framework, the architecture of the framework including the interrelations among the different components, and the internal operation of the flow management components. These issues are combined to arrive at an overall solution that yields a running design flow management system implemented in the NELSIS CAD framework. The net result is a CAD system that makes the graphical representation of the design tasks the basis for all design actions. The system provides generic mechanisms applicable to many application domains, and thus new tools can be easily incorporated.>

In this paper a new approach for design jlow management is presented.We describe how the inputlouput relations between tools can be defined in a j%nwnap.For this, several concepts are introduced, such as defiing activities for tools, run-time activity identification, hierarchical jlow graphs, modijkation versus extension, and the possibility to have loops in the j?owmap.We also address tool scheduling and the integration of design Jow management in the architecture of afiarne-bared &sign system.