错误参数类型错误当我运行程序后,输入插入点,提示:错误:参数类型错误:numberp:nil为什么我用autolisp编制绘向心球轴承的二维图形,程序如下:(defunc:zch(ppppppppppppppppppcpcafxfxt)(setqd(getreal"n输入轴承外径"))(setqd(getreal"n输入轴承内径"))(setqb(getreal"n输入轴承宽度"))(if(>d)(setqt)t为绘制刨面线的线间距比例因子(setqt))(setqa((dd)))计算三个中间参数值(setqfx(pi))(setqfx((*pi))))(setqp(getpoint"n输入图形插入点:"))(setqp(polarpfx(d)))(setqp(polarpb))(setqpc(list((carp)(b))((cadrp)((da)))))(setqpc(polarpcfx(da)))(setqp(polarpc((*pi))(a)))(setqp(polarpc((*pi))(a)))(setqp(polarpc(pi)(a)))(setqp(polarpc((*pi))(a)))(setqp(list(carp)(cadrp)))(setqp(list(carp)(cadrp)))(setqp(list(carp)(cadrp)))(setqp(list(carp)(cadrp)))(setqp(polarpfxa))(setqp(polarpfxa))(setqp(polarpfx(d)))(setqp(polarpb))(setqp(polarpfx(d)))(setqp(polarpb))(nlayer)调用层设置函数(command"zoom""w"(polarpfx)(polarpfx))(command"layer""s""")绘制轴承的上半部分(command"pline"pppp"")(command"arc"p"ce"pc"a")(command"pline"ppp"")(command"pline"ppp"")(command"arc"p"ce"pc"a")(command"pline"ppppp"")(command"pline"pp"")(command"arc"p"ce"pcp)(command"arc"p"ce"pcp)(command"mirror""w"pp""p(polarpb)"")镜像绘制轴承的下半部分(command"pline"pp"")(command"pline"pp"")(command"layer""s""")(command"hatch""ansi"t"""w"pp"")绘制剖面线(command"hatch""ansi"t"""w"pp"")(command"hatch""ansi"t"""w"p(polarpfx(a))"")(command"hatch""ansi"t"""w"p(polarpfx(a))"")(command"layer""s""")(command"pline"(polarppi)(polarp(b))"")绘制轴承中心线(command"pline"(polarpcfx(*(a)))绘制滚珠中心线(polarpcfx(*(a)))"")(command"pline"(polarpcpi(*(a)))(polarpc(*(a)))"")(command"pline"(polarpcfx(*(a)))(polarpcfx(*(a)))"")(command"pline"(polarpcpi(*(a)))(polarpc(*(a)))"")(command"zoom""a")(command"regen"))(defunnlayer()(command"layer""n""c""""continuous""")(command"layer""n""c""""dashed""")(command"layer""n""c""""center""")(command"layer""n""c""""divide"""))