A system for determining the elevation of a part of an implement, with the implement being attached to the ends of a pair of lift arms of a loader machine, includes a laser transmitter providing a reference beam of laser light. The beam may be a thin beam that is swept in a reference plane, or it may be a pair of fan shaped beams that are continuously rotated. A first beam detector is mounted on one of the pair of lift arms of the loader machine for detecting said reference beam and providing a first output. A second beam detector is mounted on the same lift arm and is spaced along the lift arm from the first beam detector for detecting the reference beam and providing a second output. A control circuit, responsive to the first beam detector and to the second beam detector, determines the elevation of the part of the implement based on the first and second outputs, and provides a projected implement elevation.