Abstract: Disclosed is an apparatus and method for cutting or marking fish fillets and other foodstuffs of varying cross-section into portions of predetermined size by conveying each product through a volume scanning unit, computing correct cut locations, and then cutting or marking at each location using a guillotine-type knife mechanism. The guillotine-type knife mechanism moves in a longitudinal direction while cutting perpendicular to the conveyor surface. Dislocation of the fillet is eliminated by synchronizing knife speed with the conveyor, and by overcoming resistance of blade retraction with a retraction mechanism.