1. A method for processing data in a data processing system to identify one or more candidate modifications to one or more physical features of a mechanical device by: converting, using the data processing system, a representation of the mechanical device into a representation of one or more surface elements; based on the representation of the plurality of surface elements, computing, using the data processing system, an effect on one or more evaluation criteria of the mechanical device of each of a plurality of design variables in a design space, each design variable facilitating an alteration to the design of the mechanical device; converting, using the data processing system, the design variables and data indicative of the computed effect into vectors; computing, using the data processing system, a design direction for the one or more evaluation criteria using the vectors, with the design direction comprising a combination of design variable settings to improve the one or more evaluation criteria, and specifying a vector in the design space, wherein the design direction indicates a direction in the design space that points from a starting design towards a local optimum design; and generating, using the data processing system, a physical modification specification for the mechanical device based on the design direction.