【摘要】 为了实现在虚拟ACL手术中对骨骼模型进行钻孔操作的动态模拟,提出了一种针对面网格模型的改进布尔操作方法.首先对与切割曲面相交的三角形进行细分,并移动切割曲面附近的网格顶点使其位于曲面上,实现模型表面上的布尔操作;然后对切割曲面附近的模型表面进行平滑处理,以消除在顶点移动操作中带来的模型表面锯齿状现象;最后采用前沿推进方法生成模型的内壁网格,并利用基于时间的钻孔深度控制函数实现对钻孔操作过程的动态模拟.该方法消除了近似布尔方法中的"T"型点问题,能够保持模型表面平滑效果和切割边缘尖锐特征,实现了对布尔操作的动态模拟,满足实时性的要求.该方法适用于实时系统中针对面网格模型的动态、交互式布尔操作模拟.更多还原

【Abstract】 An improved Boolean operation algorithm for surface mesh models is proposed which successfully simulates the dynamic drilling process on bones in virtual ACL (anterior cruciate ligament) surgery. The algorithm adjusts all the triangles on the mesh model that intersect with the cutter surface by shifting their outside vertices onto the cutter surface. These triangles are further subdivided if necessary and the positions of the concerned vertices are adjusted so that the line segments of the shifted vertices can approximate the intersection line under a given tolerance. The surface mesh of the resulting tunnel is dynamically generated with Advancing Front Method. The presented method resolves the T-junction problem in other approximate Boolean operation approaches,and it is able to preserve both the surface smoothness and the sharp features. Experiments show the real time performance of our approach.更多还原