Effective utilisation of Stereolithography (SL) mainly relies on orienting and packing parts optimally on the fabrication platform of the machine, so to achieve maximum space utilisation and minimum
build time, without of course compromising surface quality. The present work focuses on an effective way to pack parts optimally on the fabrication platform of SL machine. Due to technical constrains set by SL technology, the original 3-D packing problem is simplified by one dimension by projecting each one of the parts on the build platform (x-y plane) and packing their projections instead of the actual parts themselves. In order to solve the resulting 2-D packing problem a heuristic method has been adopted. The heuristic method consists of a Simulated Annealing algorithm employing a polynomial-time cooling schedule and a new improved placement rule.