udec中使用gen edge 命令进行单元划分，但是结果出现个别的block无法完成zone划分，急求解决办法。 出现错误命令如下：
*** Zone generation for this block failed --- to deal with this problem do one of the following:
a. continue problem using smaller zone edge length;
b. repeat problem with larger rounding length (see round) or larger minimum edge length (see set edge)
UDEC’s zone generation algorithm has failed to zone this block
改了round 等命令后仍然不行，急求解决办法
