Each 5 axis Guide Surface Iso Cut operation must have drive surface(s) selected in its feature list with general surfaces input as the cutting target. The guide surface defined by a drive surface forces tool axis to follow its normals along the isolines.
The offset 3D cut operation is used when a smooth and continuous tool path is required in the vicinity of steep walls, milling in uncut or uncutable places or when milling the entirely part as a whole.
The drive curve cut operation is similar to the offset 3D cut that starts from a custom set of curves. The starting curves can be open or closed. In general it is used like the flowing cut for milling along features.