Plant Surface Modeling And Its Application Based On NURBS

The technique for free-form curves and surfaces plays a vital role in computer-aided geometry design (CAGD). As a free-form curves and surfaces sculpting method, non-uniform rational B-spline has become a criterion in computer-aided design(CAD) and computer-aided manufacture(CAM) for its'uniform mathematical expression.In this work, consider about the shape of crop and the requirement of realistic simulation, we, based on the knowledge of NURBS, extended the theory of ball B-spline to ring B-spline. The method of modeling based on ring B-spline has been proposed. Firstly,3-dimension data points can be got by 3d scanner or digitizer. Then centerline and contour lines can be resolved according to different B-spline basis functions. Finally, the normal vector can be used in order to simulate the bend of branches. The visualized models of pepper, cucumber and corn have been simulated through different forms of ring B-spline. Particularly, the algorithm has been improved for to handle arbitrary shape of corn models.Besides, we propose a novel algorithm for inserting of control points in the T-mesh which is already applied in spline merging. Firstly, the fruit can be cut into several parts according to the contour of pepper. Secondly,3-dimension data points can be got via 3d scanner and each part of pepper can be simulated with NURBS surface. Finally, A complete bell pepper model will be obtained by merging every part due to T-splines merging algorithm.