如何把UCS对齐于弧或圆

newer · 发表于 2016-8-1 18:24:57

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本帖最后由 newer 于 2016-8-1 18:27 编辑

问题：
我需要把UCS对齐于弧线实体，我试了用UCS命令跟着E选项，但是我不能控制X、Y的旋转角，我要如何做才能把UCS对齐于弧线呢？
I need to align the UCS with an arc entity in my drawing. I tried using UCS
command with the Entity (E)option, but I have no control over the rotation of
the X and Y axes. How can I set my UCS to correspond with the geometry of my
arc?

回答：
You can use ActiveX from within AutoLISP to create your own UCS based upon the
geometry of your arc entity. Using ActiveX, you can obtain the arc's normal and
create a vector between the center and the startpoint, then calculate the third
axis from the cross product of the two. Use the Add method of the AcadUCSs
object to create a custom UCS based on the origin of the arc and points along
the X and Y axes, then make the new custom UCS current. The result will change
the UCS to make the origin correspond with the Arc's center, the Y axis will
point to the Startpoint ,the Z Axis will correspond with the arc's normal and
the X Axis will be calculated to be orthogonal to both according to the
right-hand rule. The same solution can be used with circle entities as well with
only slight modifications.

The following example is written n in Visual LISP that performs the operation:
QQ截图20160801182059.png

(defun C:UcsArc ()
(vl-load-com)
(setq acadObject (vlax-get-acad-object))
(setq acadDoc (vla-Get-ActiveDocument acadObject))
(setq anEnt (entsel "Select an Arc: "))
(if anEnt
(progn
(setq entLst (entget (car anEnt) '("*")))
(if (equal (cdr (assoc '0 entLst)) "ARC")
(progn
(setq arcObj (vlax-ename->vla-object (car anEnt)))
(setq strtPt (vla-Get-StartPoint arcObj))
(setq strtPtLst (vlax-safearray->list (vlax-variant-value strtPt)))
(setq ctrPt (vla-Get-Center arcObj))
(setq ctrPtLst (vlax-safearray->list (vlax-variant-value ctrPt)))
(setq Norm (vla-Get-Normal arcObj))
(setq NormLst (vlax-safearray->list (vlax-variant-value Norm)))
(setq startVector (doListMinus strtPtLst ctrPtLst))
(setq r1Vector (doCrossProduct NormLst startVector))
(setq XAxis (doListMinus ctrPtLst r1Vector))
(setq UCScollection (vla-Get-UserCoordinateSystems acadDoc))
(setq ucsOrigin (vlax-3d-Point ctrPtLst) XAxisPoint (vlax-3d-Point
XAxis) YAxisPoint (vlax-3d-Point strtPtLst))
(if (setq newUCS (vla-Add UCScollection ucsOrigin XAxisPoint
YAxisPoint "ArcUcs"))
(princ "Created UCS Definition: ArcUcs"))
(vla-put-ActiveUCS acadDoc newUCS)
(if(not(vlax-object-released-p arcObj))
(vlax-release-object arcObj))
(if(not(vlax-object-released-p UCScollection))
(vlax-release-object UCScollection))
)
)
)
)
(if(not(vlax-object-released-p acadObject))
(vlax-release-object acadObject))
(if(not(vlax-object-released-p acadDoc))
(vlax-release-object acadDoc))
(princ)
)
; (setq FstLst strtPtLst S**Lst ctr)
(defun doListMinus (FstLst S**Lst)
(setq X (- (car FstLst) (car S**Lst)))
(setq Y (- (cadr FstLst) (cadr S**Lst)))
(setq Z (- (caddr FstLst) (caddr S**Lst)))
(list X Y Z)
)

(defun C:UcsArc () 
 (vl-load-com) 
 (setq acadObject (vlax-get-acad-object)) 
 (setq acadDoc (vla-Get-ActiveDocument acadObject)) 
 (setq anEnt (entsel "Select an Arc: ")) 
 (if anEnt 
   (progn 
     (setq entLst (entget (car anEnt) '("*"))) 
     (if (equal (cdr (assoc '0 entLst)) "ARC") 
            (progn 
              (setq arcObj (vlax-ename->vla-object (car anEnt))) 
              (setq strtPt (vla-Get-StartPoint arcObj)) 
              (setq strtPtLst (vlax-safearray->list (vlax-variant-value strtPt))) 
              (setq ctrPt (vla-Get-Center arcObj)) 
              (setq ctrPtLst (vlax-safearray->list (vlax-variant-value ctrPt))) 
              (setq Norm (vla-Get-Normal arcObj)) 
              (setq NormLst (vlax-safearray->list (vlax-variant-value Norm))) 
              (setq startVector (doListMinus strtPtLst ctrPtLst)) 
              (setq r1Vector (doCrossProduct NormLst startVector)) 
              (setq XAxis (doListMinus ctrPtLst r1Vector)) 
              (setq UCScollection (vla-Get-UserCoordinateSystems acadDoc)) 
              (setq ucsOrigin (vlax-3d-Point ctrPtLst) XAxisPoint (vlax-3d-Point 
XAxis) YAxisPoint (vlax-3d-Point strtPtLst)) 
              (if (setq newUCS (vla-Add UCScollection ucsOrigin XAxisPoint 
YAxisPoint "ArcUcs")) 
                (princ "Created UCS Definition: ArcUcs")) 
              (vla-put-ActiveUCS acadDoc newUCS) 
              (if(not(vlax-object-released-p arcObj)) 
                (vlax-release-object arcObj)) 
              (if(not(vlax-object-released-p UCScollection)) 
                (vlax-release-object UCScollection)) 
              ) 
            ) 
     ) 
   ) 
 (if(not(vlax-object-released-p acadObject)) 
  (vlax-release-object acadObject)) 
 (if(not(vlax-object-released-p acadDoc)) 
  (vlax-release-object acadDoc)) 
 (princ) 
) 
 
; (setq FstLst strtPtLst S**Lst ctr) 
(defun doListMinus (FstLst S**Lst) 
 (setq X (- (car FstLst) (car S**Lst))) 
 (setq Y (- (cadr FstLst) (cadr S**Lst))) 
 (setq Z (- (caddr FstLst) (caddr S**Lst))) 
 (list X Y Z) 
)

求叉积的函数：

游客，如果您要查看本帖隐藏内容请回复

HLCAD · 发表于 2016-8-2 07:42:55

谢谢版主的源码，回复，向版主学习

HLCAD · 发表于 2016-8-2 07:46:06

谢谢版主的源码，回复，向版主学习

csharp · 发表于 2016-8-2 10:16:23

有点和 firstderiv 就有了原点、X 轴和 xy 平面上点，使用 UCS 命令也可以

819534890 · 发表于 2016-8-2 12:20:24

good good.

ssddssdd · 发表于 2016-8-2 12:52:59

向版主学习

q3_2006 · 发表于 2016-8-2 17:34:47

对齐于圆弧怎么讲...

王子 · 发表于 2016-9-4 20:49:36

我也正在学习ucs命令

kqqt6236 · 发表于 2016-11-20 19:13:22

　精彩好文。

434939575 · 发表于 2017-7-21 13:01:07

回复学习下！多谢分享！

liulisheng · 发表于 2020-1-17 14:05:12

顶一顶顶一顶

lee3737 · 发表于 2020-2-3 00:18:21

回复学习下！多谢分享！

yoyoho · 发表于 2020-2-3 18:14:51

回复学习！谢谢分享！

scnjlwb · 发表于 2020-2-5 15:15:47

多谢分享！

ynhh · 发表于 2022-12-28 12:24:43

谢谢版主的分享

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