恩,或许有同事或者同学会有用。先上效果图
完成这个动作很麻烦,先要延长到交点,然后再打断,然后再变换图层,才能正常标注,很伤脑筋。。。于是求助某论坛做了个程序。
;绘制圆弧切线 (defun c:tt (/ last_obj last_se obj obj_data obj_data_list obj_i obj_name n plst ss var1 var2 ) (princ "\n<----圆弧切线---->") (princ "\n请选择圆弧,多段线/<退出>...") (setq var1 (getvar "cmdecho")) (setq var2 (getvar "osmode")) (setvar "cmdecho" 0) (setvar "osmode" 0) (setq n 0) (setq obj (ssget '((0 . "*POLYLINE,ARC")))) (if obj (repeat (sslength obj) (setq ent (entget (ssname obj n))) (if (= (cdr (assoc 0 ent)) "ARC") (progn (setq plst (sys_get_pt_arc_tan ent)) (command "_.line" (car plst) (caddr plst) "") (command "_.line" (cadr plst) (caddr plst) "") ) ) (if (= (cdr (assoc 0 ent)) "LWPOLYLINE") (progn (setq last_obj (ssget "p")) (setq obj_data_list '()) (setq ss (ssadd (ssname obj n))) (command "_undo" "mark") (command "_explode" ss) (setq last_se (ssget "p")) (if (not (eq last_se last_obj)) (progn (setq obj_i -1) (repeat (sslength last_se) (setq obj_name (ssname last_se (setq obj_i (1+ obj_i)))) (setq obj_data (entget obj_name)) (if (= (cdr (assoc 0 obj_data)) "ARC") (setq obj_data_list (append (list obj_data) obj_data_list)) ) ) ) ) (command "_undo" "back") (if obj_data_list (foreach i obj_data_list (setq plst (sys_get_pt_arc_tan i)) (command "_.line" (car plst) (caddr plst) "") (command "_.line" (cadr plst) (caddr plst) "") ) ) ) ) (setq n (+ n 1)) ) ) (setvar "cmdecho" var1) (setvar "osmode" var2) (princ) ) (defun sys_get_pt_arc_tan (ent / cen jdq jdz p1 p2 p3 p4 p5 rad) (setq cen (cdr (assoc 10 ent)));获取圆弧圆心 (setq rad (cdr (assoc 40 ent)));获取圆弧半径 (setq jdq (cdr (assoc 50 ent)));获取起始角度 (setq jdz (cdr (assoc 51 ent)));获取终止角度 (setq p1 (polar cen jdq rad);获取圆弧起始点 p2 (polar cen jdz rad);获取圆弧终止点 p3 (polar p1 (+ (/ pi 2) jdq) rad);获取起始点切线方向的半径点 p4 (polar p2 (+ (/ pi 2) jdz) rad);获取终止点切线方向的半径点 p5 (inters p1 p3 p2 p4 nil);切线交点 ) (if (not p5) (princ "\n切线无交点...") (list p1 p2 p5) ) )
使用办法:
1.复制代码保存为tt.lsp,存到某个地方;
2.工具-自定义-界面-lisp文件上右键选择加载,确定
3.敲入tt命令使用,可框选,选则圆弧即可
顺便,常用的还有个打断于点,这个有图标命令,但是木有快捷键,两只手总比一只手有速度,于是自己做了一个:
;打断于点 (defun c:dd () (command "_break" pause "f" pause "@") )
这个功能你用 D 命令设计标尺线应该就能简单解决。定义全局样式,固定延长线,即使你选的两点不一样,延伸线也会一样。
回复