This paper describes GGOAL, a genetic algorithm for the minimization of glass loss in cutting large sheets into several pieces. The algorithm takes into account several industrial constraints, stemming both from the glass cutting technology and from the requirement that the optimization must run in real-time, concurrently with the cutting operation. The algorithm delivers comparable or better results than optimization procedures embedded in comprehensive commercial software systems, and is now distributed with all flat glass cutting machines sold by Bottero SpA.