如何获得多段线中圆弧的中间点坐标？

hahthx-zyp

如何获得多段线中圆弧的中间点坐标？我在网上下了一个可以把多段线顶点坐标输出的程序，但发现有圆弧时，只输出圆弧的起始点及结束点。

ljttjl

思路：得到多段线对象的图元数据后，获取42组码和其前一个10组码和后一个10组码，然后根据42组码值的正负,用polar可取得圆弧中点。

Andyhon

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From:  Doug Broad - view profile
Date:  Tues, Feb 11 2003 4:56 am 
Email:   "Doug Broad" <dbr...@earthlink.net>

Luis,
For 2D work with UCS = world this would be OK.
If you have arcs in 3D or a current UCS <> World then
you will have to do a lot more work.  Also, in order to
apply it within commands, you should either turn off
osnaps or ...
|;

(defun midarc (ent / dxf ent info cen sa ea da ma)
  (defun dxf (k l) (cdr (assoc k l)))
  (and
    ent
    (setq info (entget ent))
    (= "ARC" (dxf 0 info))
    (setq cen (dxf 10 info))  ;center
    (setq sa (dxf 50 info))  ;start
    (setq ea (dxf 51 info))  ;end
    (setq da (- ea sa))
    (setq da (if (minusp da)
        (+ (* 2 pi) da)
        da
      )
    )
    (setq ma (+ sa (/ da 2)))
  )
  (if ma
    (polar cen ma (dxf 40 info))
  )
)

不死猫

;by nonsmall

;曲线中点坐标

(Setq ob (Vlax-Ename->Vla-Object (car (entsel))))
(getpoint (vlax-curve-getPointAtDist ob (* 0.5 (vlax-curve-getDistAtPoint ob (vlax-curve-getEndPoint ob)))))

czcxxx

谢谢分享！！！！！！！！！！！！！！