In the tide of the digital transformation, the mode and process of modern ship design have undergone revolutionary transformation compared to the previous 2D design drawings due to the emergence of various digital design tools. With the continuous improvement of computer processing and the continuous deepening of the intelligent development of design software, 3D Digital Mock-Up（3D DMU）has gradually become the infrastructure of new industrial designs. Modern ship design is a customized and discrete large-scale engineering design. The introduction of 3D DMU and its extension to 3D digital ship mode will bring significant changes to the ship design process and its connotations, and the “Single Source of Truth（SSOT）” based on the 3D DMU will reshape the entire ship design process. This article focuses on the significant changes of 3D DMU and SSOT to the ship design through the analysis of the changing paradigm of modern ship design.

The aesthetic design is essential for the design of the luxury Ro-Ro passenger ship, and window design is one of the elements for the aesthetic design of luxury Ro-Ro passenger ships. However,large windows in public areas can meet the aesthetic design requirement, but impose challenges to the structural design. The fatigue strength of the opening corner of the large porthole has been studied for the 866 passenger/4 850 meter Ro-Ro passenger ship. The design method of the porthole in the specification is briefly introduced, and the basic method to reduce the fatigue stress of the porthole is presented in detail based on the finite element analysis of the whole ship. The alternative schemes are compared and analyzed. The optimal scheme is then selected to meet the fatigue stress requirement of the window frame, which theoretically prevent the fatigue crack of the window frame and the resulting glass breakage. It can provide reference for the design of the similar ships.