Shipbuilders and suppliers, through their engineering activities, generate an extensive array of shape data for ship structures. However, visualizing the entire shape of a ship on a computer for design optimization or digital evaluation poses a practical challenge. Additionally, it becomes necessary to simplify the boundary representation (B-Rep) shape during data exchange between partners using different computer-aided design (CAD) systems and when creating lightweight shape contents for digital twin implementation. In this paper, we propose a shape simplification method for converting shapes between ship CAD model and virtual reality (VR) mesh model. During the process of reconstructing the ship CAD model into a B-Rep shape, topology decima- tion is performed to remove unnecessary elements. Furthermore, bounding boxes are created for the sub-primitives of the reconstructed B-Rep shape, and the level of detail for shape simplifica- tion is determined by calculating threshold values for these boxes. Sub-primitives with the applied level of detail can be dynamically removed from the assembly model. By utilizing this method, our shape simplification system, ShipCADOptimizer, allows users to review model sim- plification results in real-time through its simplification functionality. Users can simplify the model while preserving its characteristics by setting appropriate weights and thresholds based on the intended use.
