An object model, having a plurality of features and described by a model state, is registered in an image. The cappingpurging mechanism has two rotatable turrets arranged so that each turret is associated with a respective one of the printheads and an actuating mechanism for selectively rotating and moving each turret. Variable placement net fasteners also are detailed. In a preferred implementation, the inputoutput subsystem includes a channel subsystem and a plurality of inputoutput devices, and the data logout command is sent to one of the inputoutput devices. Optional attributes include a link to a price table which contains further attributes, including a pricing method. Thereafter, the inverse kinematics and the forward kinematics are alternately repeated, and a rotational angle when the difference x is equal to or less than a predetermined value is set as a rotational angle after correction has been executed, thereby a commanded rotational angle j in which bending has been corrected is determined.