1. A method of performing a process on an existing array of features on a workpiece supported on a fixture, the method comprising: i) selecting at least three, but not all, of the features of the array; ii) identifying the nominal position in a coordinate space of each of the selected features, and generating a nominal position data set for the selected features; iii) identifying the actual position in the coordinate space of each of the selected features, and generating an actual position data set for the selected features; iv) generating an algorithm to transform the nominal position data set to the actual position data set; v) applying the algorithm to the nominal positions of the non-selected features of the array to generate actual positions of the non-selected features; vi) performing the process on the selected and non-selected features at the respective identified and generated actual positions.