应该是多了一个回括,
你试试看:
 - ;========arcL========
- ;已知同弧的弧长及弦长、弧长及弓高、弦长及弓高,求半径及画圆弧
- (defun C:arcL()
- (setq xtblm '("cmdecho" "osmode")
- xtblz (mapcar 'getvar xtblm) ;获取系统变量的原始值
- )
- (mapcar 'setvar xtblm '(0 33));对系统变量初始化
- (command "_undo" "de") ;设置撤消命令的起点
- ;设置选择画弧方式的关健字
- ;L为按“弧长弦长”方式画圆弧(默认方式)
- ;H为按“弧长弓高”方式画国弧
- ;C为按 "弦长弓高"方式画圆弧
- (initget "L H C")
- (setq htbz(getkword "\n画弧方式〔L一弧长弦长/H一弧长弓高/C一弦长弓高〕<L>:"))
- (if(= htbz nil)(setq htbz "L"))
- (if(wcmatch htbz "L,H")(setq L(getreal "\n弧长:")))
- (if(wcmatch htbz "L,C")(setq C(getdist "\n弦长:")))
- (if(wcmatch htbz "H,C")(setq h(getdist "\n弓高:")))
- ;当“弧长弓高”方式画圆弧时,询问是劣弧还是优弧
- ;将圆心角<l.5pi的圆弧都视为劣孤
- (initget "Y N")
- (if(= htbz "H")
- (if(= (setq yh(getkword "\n 劣弧[Yes/No]<Y>:"))nil)
- (setq yh "Y")
- )
- )
- (setq eps le-10 ;设定迭代精度e=10^-10(即10的负10次方)
- x 0
- xi (* 1.0 pi);初值
- )
- (if (and (= htbz "H")(= yh "N"))(setq xi (* 2.0 pi)))
- (if(wcmatch htbz "L,C")(setq xi (* 2.0 pi)))
- ;牛顿迭代法求圆心角
- (while(>(abs(- xi x)) eps)
- (setq x xi)
- (if(= htbz "L")
- ;已知圆弧长度及弦长的迭代
- (setq fx(-(* 2.0 L (sin(/ x 2.0)))(* c x))
- dfx(-(* L (cos(/ x 2.0)))c)
- )
- (if(= htbz "H")
- ;已知圆弧长度及弓高的迭代
- (setq fx (- L (* L (cos(* 0.5 x)))(* h x))
- dfx(-(* 0.5 L (sin(* 0.5 x)))h)
- )
- ;已知圆弦长度及弓高的迭代
- (setq fx (-(* 2.0 h (sin(* 0.5 x)))(* -1.0 c (cos(* 0.5 x)))c)
- dfx(-(* h (cos(* 0.5 x)))(* 0.5 c (sin(* 0.5 x))))
-
- )
- )
- )
- (setq xL (- x (/ fx dfx)))
- )
- ;由圆心角计算出半径
- (if(wcmatch htbz "L,H")
- (setq r (/ L xL))
- (setq r (/ c 2.0 (sin(* 0.5 xL))))
- )
- (princ "\n解算出的半径R=")(princ(rtos r 2 10))
- ;根据已知数据及解算出的圆心角、半径计算弓高
- (if(= htbz "L")(setq h (* r (1-(cos(* 0.5 xL))))))
- (if(= htbz "H")
- (progn
- (setq c(* 2.0 r (sin(*0.5 xL))))
- (if(<(abs(- xL (* 2.0 pi))) 1e-6)(setq c(* 2.0 r)))
- )
- )
- ;根据指定的点、已知及解算出的数据计算圆弧的中点、止点
- (setq pt (getpoint "\n 起点:")
- pt3 (polar pt1 0 c)
- ptm (polar pt1 0 (* 0.5 c))
- pt2 (polar ptm(* 0.5 pi) h)
- )
- (setvar "osmode" 0);关闭对象捕捉功能
- ;调用CAD已有的三点画圆弧命令画圆弧
- (command "_arc" pt1 pt2 pt3)
- (setvar "osmode" 33);设置对象捕捉(捕捉端点和交点)
- (princ "\n止点方向:")
- ;动态将固弧旋转到指定方向
- (command "_rotate" (entlast) "" pt1 "r" pt1 pt3 pause)
- (command "_undo" "e") ;设置撤消命令的止点
- (mapcar 'setvar xtblm xtblz);恢复系统变量的原始值
- (princ)
- )
|