[原创]判断点是否在直线或圆弧上

xinrstar

;;plrelation 函数
;;判断点是否在直线或圆弧上
;;语法：(plrelation po ename)
;;参数：po 点座标　ename 对象名
;;返回：T或nil
;;T 在对象上　nil不在对象上
(defun PLRELATION (PO ENAME / P1 P2 DI1 DI2 DI3 A R)
  (setq ENT (entget ENAME))
  (cond
    ((= (strcase (cdr (assoc 0 ENT))) (strcase "lINE"))
     (setq P1 (cdr (assoc 10 ENT))
    P2 (cdr (assoc 11 ENT))
     )
     (setq DI1 (distance PO P1)
    DI2 (distance PO P2)
    DI3 (distance P1 P2)
     )
     (if (= (+ DI1 DI2) DI3)
       (setq A t)
       (setq A NIL)
     )
    )
    ((or (= (strcase (cdr (assoc 0 ENT))) (strcase "ARC"))
  (= (strcase (cdr (assoc 0 ENT))) (strcase "CIRCLE"))
     )
     (setq P1 (cdr (assoc 10 ENT))
    R  (cdr (assoc 40 ENT))
     )
     (setq DI1 (distance PO O))
     (if (= R DI1)
       (setq A t)
       (setq A NIL)
     )
    )
  )
)

byghbcx

判断不完善,需更改!

highflybir

如果是Vlisp就简单多了。

3. (defun if_on_curve (pt curve / closept)
4.   (setq closept (vlax-curve-getclosestpointto curve pt))
5.   (equal (distance closept pt) 0 1e-8)
6. )

(defun if_on_curve (pt curve / closept)   (setq closept (vlax-curve-getclosestpointto curve pt))   (equal (distance closept pt) 0 1e-8) )

以下为测试:

3. (vl-load-com)
4. (defun C:test (/ perpt e pt)
5.   (if (setq e (car (entsel "\nPlease select a Curve or Line:")))
6.     (if (setq pt (getpoint "\nPlease Enter a Point:"))
7.       (if_on_curve pt e)
8.     )
9.   )
10. )

(vl-load-com) (defun C:test (/ perpt e pt)   (if (setq e (car (entsel "\nPlease select a Curve or Line:")))     (if (setq pt (getpoint "\nPlease Enter a Point:"))       (if_on_curve pt e)     )   ) )

问题青年B

能否说一下最好的思路?

通过距离还是角度或者其他?

无痕

用ｖｌ还可以更简单吧？

2. ;| (oncur e pt)判断点在曲线上
3. 返回: 非nil(在曲线上)
4. |;
5. (defun oncur (e pt)
6.   (vlax-curve-getdistatpoint e pt);;vlax-get-paramatpoint
7. )

;| (oncur e pt)判断点在曲线上 返回: 非nil(在曲线上) |; (defun oncur (e pt)   (vlax-curve-getdistatpoint e pt);;vlax-get-paramatpoint )

2. ;;测试
3. (defun c:tt()
4.   (oncur (car(entsel "\n 选曲线:"))(getpoint "\n 选点:"))
5. )

;;测试 (defun c:tt()   (oncur (car(entsel "\n 选曲线:"))(getpoint "\n 选点:")) )