1. A method for performing geometric dimension and tolerance stack-up analysis for an assembly, the method comprising: receiving a target assembly dimension for stack-up analysis, wherein said assembly includes at least one part; receiving a feature corresponding to said part; receiving feature tolerance data associated with said feature, wherein said feature tolerance data includes at least one of size tolerance and geometric tolerance; accessing stack-up rules in response to said receiving feature tolerance data, wherein said stack-up rules include: instructions to determine if a form tolerance, an orientation tolerance and a profile tolerance should be included in a stack-up tolerance for said feature; and formulas to calculate a nominal dimension and said stack-up tolerance for said feature when said feature tolerance data applies to feature of sizes; deriving said nominal dimension and said stack-up tolerance for said feature responsive to said stack-up rules and to said feature tolerance data; and performing said stack-up analysis in response to said nominal dimension and to said stack-up tolerance, wherein said performing results in a mean and a standard deviation for said target assembly dimension.