A significant challenge preventing wider industrial adoption of electrochemical machining (ECM) is the lack of efficient, a priori means for selection of a tool design to achieve a target part shape with high accuracy. Tight coupling among the numerous physical phenomena active in industrial electrochemical processes confounds the simplification approaches available in other contexts. Recent developments in computational hardware and software allow simultaneous solution of the relevant governing equations, potentially enabling practical tool design methods by solution of the inverse electric field problem.'' This paper discusses recent work comparing primary current distribution simulations to indentations fabricated by ECM of steel panels. Good agreement was obtained for a subset of the tests performed. The results highlight the importance of including additional physical phenomena such as flow effects and electrochemical polarization in order to obtain more accurate simulations. In particular, the current efficiency of the metal dissolution reaction likely must be considered.