Three-dimensional control cage constructing method

The invention belongs to the field of computer graphics, and specifically relates to a three-dimensional control cage constructing method. As users has higher requirements on three-dimensional display effect, three dimensional models are used in a finer way, and summit number required is greater. Lots of applications need to construct a control cage to assist in control of a three-dimensional model. Conventional control cage constructing methods have defects. The method aims to solve the problems. The method is based on rendering streamlines. In a specific angle observation model, texture of A32B32G32R32 format which is a two-dimensional texture and can record three-dimensional information is used to generate front view and back view grid curved surfaces, which are stitched together. The grid summits are pushed outward for a certain distance according to the normal vector and observation direction to construct a control cage. Figure 1 displays a sketch map of a control cage construction of a cylindrical model. The cross section effect of the cylinder is displayed in the figure.