1. A method of a volume of activation (VOA) providing machine to provide a VOA of a stimulation electrode leadwire, comprising: calculating, by a processor of the machine, a VOA for each of a plurality of sets of parameter settings of the leadwire; storing in a database each of the calculated VOAs in association with the respective set of parameter settings for which it was calculated; obtaining a further set of parameter settings of the leadwire; determining, by the processor, a VOA for the obtained set of parameter settings based on the stored VOAs; and outputting, by the machine, the determined VOA.