The basic requirment for optimization is to produce solution with no overlap between the parts inside the sheet. Design cutting optimization strategies involve taking the pieces in order and placing them on the sheet according to a given placement policy. This procedure may be repeated several times for different orderings and the best solution chosen. The running time of design cutting optimization changes from case to case due to process mechanism. In each phase of the calculation decision is made, without regared for future consequences, and create a sub-optimal solution. The algorithm continues to push parts downwards and leftwards until the parts reach a stable positions. The order of the parts in the optimization process will essentially affect the design result. Cutting the largest area first will generate the highest utilization result. The major reason is that the empty spaces produced by great part are easily to be filled with small parts. Each group of elements is a subgroup of a layout. At the beginning of the optimization process each group contains only one element. During the optimization some groups are merged in new more large group. At each step two or more groups are merged into one new group. Finally all groups are merged into one, which represents the whole layout.
