Abstract: Method and apparatus for computer aided completion of the interconnection pattern of a printed circuit board left after an automatic interconnect routing system fails to connect all points needing connection. The invention utilizes operator and/or automatic intervention in combination with system provided indicia representative of regions, about each of a set of points to be interconnected on the board, where conductors can be placed according to predesignated interconnect protocols or constraints. The system provides selectable logical operations on the regions that permit operator display of indicia from which the operator can intervene to complete the interconnection by providing a minimal sacrifice of protocols or through automatic intervention to complete the interconnect pattern between points in each region according to a data base of acceptable protocol modifications.

Abstract: A computer aided design system which results in reduced operator fatigue, increased speed, and increased accuracy features a single workspace for inputting information, such as type of drafting exercise, graphic element or symbol, element position established either by element coordinate designation or cursor tracking and alpha/numeric keyboard-like entries. The system utilizes dual CRT screens, one, the graphics screen, for viewing the end product of the graphic design and the other, the function screen, for providing a single workspace for entering data. In one embodiment, input data either in the form of fixed format blocks or sequentially presented menus are displayed to the operator at the function screen so that he may select appropriate inputs with a light pen. Because all types of inputs are accomplished at a single workspace, the single workspace function screen avoids eye and arm fatigue so that the operator (i.e.