Generating the support for a wide range of parts for some RP process is crucial to finish the part and keep the manufacturing precision. However, it is difficult to accomplish and at present, no algorithm of automatic support generation (ASG) can be applied to general cases yet. Two ASG algorithms, a curve tracing algorithm and a marking-point tracing algorithm, are introduced in detail and illustrated in examples. The former is performed before slicing to reconstruct support surface patches by skinning method from traced sampling points while the latter is performed after slicing to compute the practical and the comprehensive contours on end planes layer by layer, which is also another way to perform Boolean operations on polygon sets. Both algorithms form a new ASG scheme which is proved effective, efficient and convenient by the examples.%在一些RP工艺中,给各种形状的零件添加支撑对于完成零件的制造和保证零件的精度非常重要,但目前尚无很好的自动添加支撑算法能够应用于一般的情况. 为此提出两种自动添加支撑算法:曲线追踪法和标志位追踪法. 前者主要是在切片前基于追踪得到的采样点利用蒙面法重构支撑面片;而后者则是在切片后通过多边形的布尔运算逐层计算各切层端面的实际轮廓和综合轮廓. 这两种算法形成了一种新的自动添加支撑方案. 实例证明了这种方案的有效性和便利性.
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