Machine operations are performed by a robot at a plurality of locations on a workpiece based on off-line data. The off-line data is corrected based on two levels of workpiece/robot alignment. First the robot determines the orientation of a fixture to which the workpiece is mounted by "touching-off" on known reference points (touchblocks) on the fixture. Coordinate data for the location of local features on the workpiece is corrected based on the first level of alignment and the positions of the local features are then sensed to provide a coordinate transformation for subsequent application to nominal machine operation location coordinates. The local features may be preassembly rivets and provide for individualized robot response on a workpiece-by-workpiece basis.