If your data has overlapping surfaces or data that does not slice into good contours, use one of the projective techniques to rough the model.
1 Rough with X or Y parallel in longest part direction. Use Flat end tool
Z Increment = DEFAULT.
Stepover = 50%.
2 Semi-rough with X or Y parallel finishing perpendicular to roughing direction. Use Flat end tool.
Z Increment = leave Blank.
Stepover = 50%.