The Further Research On Interactive CAD Of The Hull Surface Based On NURBS

Nowadays, ship hull curves and surface modeling technology is an important part ofshipbuilding design. How to express the the hull surface modeling fast and accurate becomesthe research objectives of designer. NURBS algorithm was considered to be the bestalgorithm of curve and surface modeling techniques because of the inheritance of theB-spline curve and the advantages of the Bezier. So it is widely used.On this basis,shipbuilding CAD software developed has been applied to the production of the actual projectby the major ship manufacturers.In this paper, the expression of hull curve and surface is realized by the use ofprogramming, which is based on the use of NURBS algorithm. Besides, the fairing of thecurve and surface is considered, so, the paper is an effective research to the modelingtechnology of hull curve and surface.The NURBS algorithm is well analyzed in this paper, and the NURBS algorithm is usedin the aspects of the fitting of the curve and surface as below: the use of NURBS inversealgorithm realizes the fitting of the hull points. The combination use of L-order and Nodeinsertion of the NURBS algorithm is analyzed in the paper, so that the straight lines, thesecond-order arc and free curve can be expressed in a unified expression. The hull surface isfitted with the method of skin surface and the surface splicing technology.Gived an fairingexpression on the curve on the base of the analysis of the energy method and the least-squaremethod, and then use it to the construction of the curve.Find a method to fair the surface byconstructing the auxiliary lines of the hull surface, which is used in Tribon Lines.At last,develop a software to realize the functions with the use of C++and OpenGL.The software makes a good combition of NURBS and the expression of hull curve andsurface. It can be used easily, and it makes the operations intuitive and interactive.The curveand surface made by the software can meet the requir of the user. So it is an effective researchto the technology of hull curve and surface.