Patent US 6,480,193

A method for storing CAD data over a long term which includes the step of storing over a long term a rule which is a modification of a standard rule which can convert various types of CAD data created by various types of CAD programs to text-based standard data, the rule being determined such that among items contained in the various types of CAD data, items relating to contents to be archived over a long term are selected, and data obtained through conversion of the selected items are treated as long-term archived data, and the rule containing at least a procedure for designing a converter which converts the selected data items to long-term archived data, and a procedure for designing a viewer which enables display units of various computer systems to display the converted long-term archived data; the step of creating a converter on the basis of the rule, the converter operating on a selected computer system in order to convert selected CAD data to long-term archived data; and the step of converting selected CAD data to long-term archived data by use of the converter and archiving the long-term archived data over a long term.