Placement Heuristics for Irregular Packing to Create Layouts With Exact Placements for Two Moveable Items

This paper discusses cutting and packing problems, which aim to minimize wasted material and can be found in industries such as textile, shipbuilding, wood or glass. The irregular strip packing problem is a variation of such problems in which the container has variable length and fixed width. Solution proposed uses the collision free region concept and its capability to detect exactly fitting and exactly sliding placements. These types of placements represent constrained positions for the item, and it usually constitutes a local optimum placement. The adopted algorithm uses pairwise placement such that one item is always placed in a exact fitting or exact sliding position. However, several possibilities exist, and it is necessary to pick one of them. Due to its different approach for item placement, three new placement heuristics were proposed for this implementation. Each was tested with an instance taken from literature, and compared with best result from the literature. A simulated annealing algorithm controls the sequence of item placement, and the placement position is deterministically determined. This work is a first tentative to determine the best placement position among all the local optimum placements.