看着两个,揣摩一下就明白了,http://wenku.baidu.com/link?url=krikYkdWOoSPFvsgkJQO94V68mIEtEs4ForWmPtt2vvT-4aP92vDUFLZjVLihhSco9gyEvgQlYd153Qj966g7pQRLQVzXlcxcyMTVxcq4GC ,http://www.xmj1688.com/solidworks2012/1725.html