将三维模型的三角面片表示与基于体素的链码技术相结合,提出一种基于体素的三维模型面片链码表示方法.首先对三维模型进行基于体素空间的切分,将获得的面片顶点归一化在体素顶点上,构造基于体素三角面片的模型表示;然后依据构造的体素三角面片间连接边与第3顶点的位置关系定义面片链码的数据结构;再根据连接边的类型和方向计算层次三角面片法向量的大小和方向;最后通过逐层遍历体素内归一化的三角面片,获得三维模型的面片链码表示.相应地,给出了面片链码的解码方法.文中比较了面片链码与其他三维模型压缩算法的压缩效率和时间开销,计算了不同体素粒度切分的三维模型与被切分的原始模型之间以及与体素切分模型具有同级别面片数量的原始模型之间的误差,结果表明,该方法能够有效地表达三维模型.
A representation method of 3D model mesh chain code based on voxel is proposed combining triangle mesh representation of 3D model with voxel-based chain code. Firstly, the 3D model is reconstructed based on triangle mesh in the voxel by cutting the 3D model in the voxel space and normalizing the intersection obtained to the voxel vertex. After that, the data structure of mesh chain code is defined according tothe position relationship of the connection edge and the third vertex of the triangle mesh reconstructed based on the voxel. The size and direction of triangle mesh normal vector in one layer are calculated according tothe type and direction of the connection edge. Finally, the mesh chain code representing 3D model is obtained by traversing triangle mesh normalized in the voxel layer by layer. Correspondingly, decoding methodof mesh chain code is presented. The compression efficiency and time consumption are compared between the mesh chain code and other 3D model compression algorithms. The errors between the 3D models cut by the different size voxel and the original model cut by the voxel, and the original models which are the same mesh number level with the models cut by the different voxel are calculated. The result indicates that the method proposed can represent 3D model efficiently.