GibbsCAM Radial Milling drives one rotary and three linear axes to achieve 4-axis toolpath. It provides a roughing and a finishing mill process for off-centerline “Y-axis” rotary machining, allowing control of wall angles and tool engagement. Input is 3D wire-frame geometry extracted from solids or created by other means, to drive and orient the tool. Optionally, surfaces may be used to orient the tool and limit toolpath. Tool orientation control includes cutting with the side or bottom of the tool, using a surface or two curves to control tilt, following one curve at a specified lean angle, or using progressive tool lean. Toolpath is usually segmented, but can be optimized for helical motion.