Various process models have been proposed for system development, which represent all stages from requirements analysis to implementations and tests. However, these process models focus not on improvement of the model of the system itself but on the development of processes to adapt to the properties of the requirements in system development. First, we arranged the features of system development. Then, we modeled the requirements and a system, and propose here a design method by which the customer and designer can always check requirements by introducing not plural design methods using various conventional design model figures but a unified multiphase design method, even if the designer does not implement the system. The customer and designer can check the requirements using the animations of the scenarios described as requirements. Finally, we present an example of execution, which designs a system using the proposed model, and describe avenues for future work.
