Electro optical system offers laser-sintering systems that generate moulds and cores for sand casting directly from cad data, fully automatic and without requiring any patterns or core boxes. The parts are built up in thin layers by locally binding foundry sand using two computer-controlled laser beams, which scan each cross-section of the geometry in turn. Complex geometries such as free-from surfaces and undercuts can be built without problem. This opens new design possibilities for moulds, gating systems and corers, for example draft angles, are not necessary, and often enables the number of core-pieces in a mould assembly to be reduced. The sand used in similar to production materials and enables castings to be produced in all standard-casting metals for use as prototypes or small series production parts.