A laser scanning system in a rapid-protyping system is controlled during vector scanning by providing a commanded-position signal to each of first and second rotary motive devices to rotate respective mirrors of the scanning system, each mirror undergoing acceleration at the beginning of the vector, wherein the commanded-position signals are calculated based on physical mathematical modeling of the acceleration of the mirrors taking into account effects of inertia of the scanning system, and wherein actual positions of the mirrors are measured with fast-response devices and digital feedback control of the mirror positions is employed at a periodic rate sufficiently small to maintain a following error of the laser spot less than about 200 .mu.s at all times. A laser power control method employs a fast-response power meter for measuring laser power.