NFP-based nesting algorithm for irregular shapes

Abstract

This paper presents a new 2D irregular-shaped nesting algorithm, which is based on a new NFP (No Fit Polygon) algorithm and a new piece placement policy named as lowest-gravity-center policy. Compared with existing algorithms, the proposed NFP algorithm has lower time-complexity and higher robustness due to the introduction of trace lines. The proposed lowest-gravity-center policy places a piece to the position which has the lowest gravity center based on NFP. Compared with the bottom-left piece placement policy, the proposed lowest-gravity-center policy results in a relatively flat boundary for the pieces. The proposed nesting algorithm can deal with pieces with arbitrary rotation and holes. It achieved competitive layout solutions both in nesting pattern height and area-utilization ratio.