Lenght of Arc

[guyzen2004]

Is there a way to find the lenght of a portion of an arc by just clicking two points on the arc? Could a lisp be done for it?

[ReMark]

The length of an arc can be determined in a couple of ways. First, you can click on the arc and then look under Properties where just below Arc Angle you'll see an entry for Arc Length. Second, the List command can be used. This can be envoked from the command line by typing LI, hit Enter, select the object then a text window will appear. The length of arc is shown at the bottom of the windows.

 

Caveat: Since my skills haven't been updated in a while there may be other ways to accomplish this simple task that I am unaware of. Please accept my humble apologies. For further information you can ask Super Member and Ph.D. J.D. Mather what he would advise doing. I defer to his infinite wisdom and knowledge. Have a nice day.

[eldon]

Is there a way to find the lenght of a portion of an arc by just clicking two points on the arc? Could a lisp be done for it?

 

Certainly a lisp could be done for it, but it might already be out there. But for speed, you could trim the arc to the length required and find out the actual length, as in the previous post by ReMark. Then a couple of Undoes, and you are back with your original arc.

 

Of course my skills have also not been updated for a while, so there may be an up-to-date way of doing things.

[ReMark]

eldon: Say it ain't so!

 

guyzen: Looks like I misread your question. I'll take a look around for a LISP routine that would satisfy your requirements. Or I could just ask Certified Professional J.D.M.

[ReMark]

Take a look at the description to this referenced LISP routine. It might be possible to tweak it with regards to "pick points" to get the results you're looking for.

 

http://cadtips.cadalyst.com/curved-objects/compute-arc-values

[lpseifert]

Try this, not extensively tested...

osnaps not necessarily required

Edit value in red for precision

;;;reports distance between two selected points along an entity LPS 8-8-08

(defun c:idd ()
 (vl-load-com)
 (command "ucs" "w")
 (setq    ename-pline    (car (entsel "\nPick entity to be measured: "))
   vlaobject-pline    (vlax-ename->vla-object ename-pline)
   pt1        (getpoint "\nPick start point on entity: ")
   pt1a        (vlax-curve-GetClosestPointTo vlaobject-pline pt1)
   pt2        (getpoint "\nPick second point on entity: ")
   pt2a        (vlax-curve-GetClosestPointTo vlaobject-pline pt2)
   sta1        (vlax-curve-getDistatPoint vlaobject-pline pt1a)
   sta2        (vlax-curve-getDistatPoint vlaobject-pline pt2a)
   delta        (abs (- sta2 sta1))
   delta-str    (strcat
             "The distance along the entity\n between the two points is "
             (rtos delta 2 [color=Red]2[/color])
                         )
                        ;;strcat
 )
 ;;setq
 (command "ucs" "p")
 (alert delta-str)
)
;;defun

[guyzen2004]

The Idd lisp seems to work fine.

[lpseifert]

You're welcome