10. In a computer automated design system having a display, memory and multiple software tools for operating on data files representing a design, apparatus for managing design data for ease of manipulation by a user, comprising: means for providing in memory a design object type that includes a fileset definition of multiple data files representing related but distinct aspects of the design object type; means for creating an instance of the design object type, the data files of the instance each containing design data on a related aspect of a particular design represented by the instance; means for providing on the display a symbol visible to a user which represents the instance; means for associating with the design object type a software tool that is invoked upon opening of the instance; means for opening, in response to an opening of the instance, all of the data files in the fileset corresponding to the instance and combining the data of the data files to provide the particular design; and means for invoking the associated software tool for communication with the data files.
10. In a computer automated design system having a display, memory and multiple software tools for operating on data files representing a design, apparatus for managing design data for ease of manipulation by a user, comprising: means for providing in memory a design object type that includes a fileset definition of multiple data files representing related but distinct aspects of the design object type; means for creating an instance of the design object type, the data files of the instance each containing design data on a related aspect of a particular design represented by the instance; means for providing on the display a symbol visible to a user which represents the instance; means for associating with the design object type a software tool that is invoked upon opening of the instance; means for opening, in response to an opening of the instance, all of the data files in the fileset corresponding to the instance and combining the data of the data files to provide the particular design; and means for invoking the associated software tool for communication with the data files. 17. The apparatus of claim 10 wherein the associated software tool is chosen from a list of tools.