1. A method for determining a solution group of relevant parts among a plurality of parts in an assembly; said solution group being related with at least one target part of said plurality of parts; each respective part of said plurality of parts being identified by a respective part-containing volume and a respective locus; each said respective locus being identified with respect to a common origin; the method comprising the steps of: (a) identifying said respective part-containing volume of each respective said at least one target part; (b) including each said respective part-containing volume of each respective said at least one target part as part of a target-containing volume for said at least one target part; (c) identifying each respective part-containing volume for each said relevant part; each said relevant part being identified by a respective part-containing volume having a predetermined relationship with respect to said target-containing volume; and (d) assigning said relevant part to said solution group.