Design patterns provide valuable knowledge for resolving design problems. Applying design patterns to design models in the design phase can increase the flexibility, extendibility, and maintainability of a software system. However, research analyzing methods for visualizing and understanding the differences in software design models with and without design patterns is scant. This study used the design structure matrix (DSM) to analyze the relationships between class diagrams in role-playing games. DSM partitioning analysis indicated that the modularization, extendibility, and maintainability of software design models improved after applying abstract factory and strategy design patterns to class diagrams. The approach proposed in this study can help pattern users visualize design patterns and improve understanding of the design models of a software system.