Usually, the self-assembly morphology of block copolymer is dictated by the volume fraction and the interaction parameter in reality without considering the complex kinetic process. However, in simulation, a suitable dimention of the simulation box is needed if one try to obtain the consistent results with experimentations. Since the periodical boundary condition can be a constraint especially in forming some nonclassical morphologies, such as the the Frank-Kasper phases. The mismatch between the morphology and the period of the box means there should exist a suitable size for getting these phases. Is there any way to determine the optimum box demention. Any technical advices, articles, book names about this problem will be very kind help. Thanks in advance.