Abstract: A method for configuring a product from a plurality of selectable components includes establishing for each component a list of available classes, defining specific properties for each class of each component, defining constraints among components based on said specific properties, selecting a first plurality of components for a product configuration, identifying each of said first plurality of components as selectable, eliminated, or contradicted based on said constraints, and altering said product configuration to avoid eliminated and contradicted components. The method permits computer added design of a system which allows interactive participation of the designer in identifying required components for a redesign when an initial design is inoperable.