Design Point Generation Method from a Lightweight Model for Dimensional Quality Management in Shipbuilding

Abstract

A ship is constructed by assembling blocks and installing outfits in the assembled ship structure. The measured data of real products and the design data are analyzed to prevent the loss caused by dimensional quality errors in shipbuilding. In recent years, 3D shapes have been used for efficient dimension quality management; however, it is difficult to deal with the large-scale Computer Aided Design (CAD) data required for managing extra-large blocks. A lightweight model is widely used for visualizing and sharing large data in Product Lifecycle Management. Thismodel is mainly composed of triangular elements to minimize the file size and increase visibility. There are no problems with visually confirming the shape based on these triangular elements, but the model has a limitation when numerically calculating the exact position on a curve or a surface. In this article, we propose a method that uses a lightweight model to improve the efficiency of dimensional quality management. Accurate boundary curves are restored fromthe lightweight model used for visualization. Aftermatching the connectivity of triangular elements, boundary element edges are extracted. Boundary curves are generated by connecting these boundary element edges. In addition, the density for tessellation was evaluated and found to be suitable for the shipbuilding process. The proposed method was tested on several models to demonstrate its feasibility.