一种三维实体模型表面法线计算方法研究

介绍了实体模型的几何造型原理，研究了生成模型表面顶点法线的两种常规方法．针对常规方法对具有棱角的模型表面表现不准确的问题，提出了棱边分裂法，计算得到所有两个相邻三角形夹角大于阈值的共享棱边，为相关的每个顶点增加新的法线向量．具体可由棱边之间或与边界之间所夹的三角形通过常规方法计算得到，使棱边两侧的表面能正确地进行光照计算，真实反映了模型的几何特征，提高了绘制的真实感．

Research of Calculating Method for Surface Normal Line of 3D-Entity Model

In this paper,the principle of geometric modeling of the entity model is introduced.Two usual methods for obtaining the vertex normal line on the model surface are studied.The usual methods have a disadvantage on expressing the model surface with some sharp corners.So the edge splitting method is brought out,by calculating to gain the sharing edge with the angles bigger than a threshold of two adjacent triangles.New normal lines for each vertex on the edge are added,and it could be worked out by the triangl...