利用HFSS自身的做图软件怎样画弹簧啊？

画弹簧时总是能看到弹簧，但是按确定后就没有了，出现如下错误，请问那位朋友知道是怎么回事?
    [error] Acis error: "Failed to call api_sweep_with_options.. Acis Error 93009 - The helical sweep results in a self-intersecting body. " (9:45 上午  十二月 25, 2008)
    [error] Acis error: "Failed to sweep the object." (9:45 上午  十二月 25, 2008)
    [error] Body could not be created for part because of invalid parameters to Helix operation. (9:45 上午  十二月 25, 2008)