Research And Implementation Of Complex Surface Modeling Technology Based On Curvature Line NET

Curvature line is a kind of curve which is often involved in the application of surface modeling.Its distribution is closely related to the smoothness of the surface.The curvature line of surface can reflect the changing state of the surface.Therefore,in the application of surface modeling,the curvature line of the curved surface is usually restricted to be as smooth and uniform as possible.However,the existing surface modeling methods lack effective methods to directly control curvature lines on curved surfaces.In this paper,a surface shape optimization method based on target curvature line or curvature line network is proposed for B spline surfaces.Through this method,the curvature line of the B spline surface can be optimized and adjusted,so that the B spline surface can have the desired curvature line distribution of the user or have a regular curvature line network.The implementation of this method provides a new way for geometric modeling applications based on curvature line distribution of surfaces.The curvature line constraint B spline surface optimization method takes the desired target curvature line as the optimization target,constructs the minimized target function according to the geometric constraint of the curvature line,and optimizes the minimized objective function by the L-BFGS numerical optimization algorithm,so that the curvature line of the target is gradually approximated by the curvature line of the B spline surface.Based on this method,two specific application scenarios are presented in this paper: curvature line driven B spline surface editing and curved line mesh based surface modeling.The surface modeling based on the curvature line network takes the mesh model as the initial shape.Through the initialization of the surface,the surface model composed of multiple B spline surfaces is obtained.The surface model is optimized and subdivided many times,and the smooth curved surface model with the desired curvature line distribution of the designer can be obtained.The focus of the surface optimization is the curvature line network optimization,and the curvature line network optimizes the curve mesh formed by the splicing of all B spline surfaces in the model as the target curvature line.The B spline surface optimization method based on curvature constraint is used to optimize the surface model.Based on the theoretical research above,a surface modeling system based on curvature line network is designed and implemented.An example is given for the application of the system to the optimization of car body surface and the modeling of the building surface,and the results of the application examples are compared and analyzed in detail by using the high light model and the color based visualization evaluation method.It shows the effectiveness of the system function.