Abstract
The growth of 3D CAD system in ship hullform design makes curves and surfaces data use prevalent. For transmitting those data on networks in design process, the data size becomes critical. This paper describes a compression method of free-form surface for ship hullform design. It consists of surface interpolation over boundary curves and surface modification using differences between original surfaces and interpolating ones. The differences data is compressed using the discrete cosine transform (DCT). We achieved to balance data size and tolerance by the method. It enables to select effective compression ratio according to objectives of data usage.
