A curve based hull form variation with geometric constraints of area and centroid

Modifying an existing geometric shape to obtain another is a common process in automobile, aircraft, and shipbuilding design. In particular, shipyard design departments rely on hull form variation, which involves designing a new ship from a well-made existing ship, as an efficient and effective process. However, this process is inefficient as it is complicated and unintuitive, thereby reliant on highly skilled expertise. An efficient approach to perform the variation with the given geometric constraints of area and centroid is proposed. To modify an existing hull form shape, a boundary curve of the shape is selected as a design variable. A parametric piecewise polynomial curve satisfying new geometric requirements is constructed and superimposed on the top of the chosen boundary curve to yield the desired shape. The main process of the variation preserves the original shape as much as possible, which means the new shape can be obtained simply and efficiently. The proposed algorithm can be readily extended to similar modification processes involving an existing geometric shape by adopting different geometric requirements.