A method for generating a tool path to manufacture a part using a computer numerical control system includes the steps of; generating an initial design part geometry from a geometry modelling program as an input, creating a pre-finished in-process workpiece geometry before a finishing process, controlling a stock thickness distribution of the pre-finished in-process workpiece geometry by following the tool path, wherein the stock thickness distribution is based on at least one ruling function on a basis of at least one predetermined direction, wherein the at least one ruling function is used to determine a stock thickness at a tool location to obtain a variable stock thickness distribution around a design part; locating at least one tool to be defined with respect to the initial design part geometry.