Principle Of Nurbs Modeling Study

NLJRBS are widely used in CAD/CAM and graphics. This paper mainly concerns a new method of shape modifications of NURBS curves and surfaces. Since the weights were introduced into B-spline, it has become a strong tool with more flexibility for designers in shape modifications of curves and surfaces. But, only modifying the shape of curves and surfaces by modulating the their weights will not reach us .So which are discussed in this paper as follow:1.It systemically summarizes the geometry meanings of weights and the principle of the shape modification of curves and surfaces. This paper gives a method of implementing.2.It investigates the technique of decreasing the number of the control points.3.Above all, this paper searches the technique of using the weights, which is a strong tool to modifying shape of curve.4.On the basis of the shape modification of curves, it extends the technique of above to the shape modification of surfaces.5.At last, this paper improves that the method is good and excellent with examples.