Definition and fairing of ship hull using a B-spline surface

Abstract

This thesis describes the definition and fairing scheme of ship hull using a B-spline tensor product surface. In our definition scheme of ship hull, the surface is defined by a network of control points which are initially obtained from longitudinal curves or water lines on ship hull. Then the ship hull is represented completely as a 3\_D geometric model by B-spline tensor product surface. Fairing the ship hull is accomplished by controlling the network of control points or surface points in three projection planes using a graphic CRT. All the drawings such as isometrice views of whole ship hull, body plan, water lines, and buttock lines can be generated quickly by the subdivision technique of B-spline surface. And for a detailed inspection of fairness of surface, we use the contour map of Gaussian curvature isloines for the indicator of fairness. For the experimental application of our new scheme to the definition and fairing of real ship hull, we have developed a prototype software package by FORTRAN language on PRIME 750 computer system, which provides the facilities such as Curve Editor, fast rendering of B-spline surface, and contouring of Gaussian curvature isolines, and the relevant algorithms such as B-spline surface interpolation, subdivision of B-spline surface, and intersection of two B-spline surfaces are also developed in this package.