Curved line length

[cphi]

How do I determine the length of a curved line? For instance, I need to determine the length along the curved line between two points on that line. I am using ACAD 2000 or 2004LT. I am also not well educated in using AutoCAD. Thanks for the help.

 

[IFRs]

You need to trim the arc at the points, then do List or Area. If the arc is part of a polyline and the endpoints of the arc are on the polyline, List may give you the segment length. Otherwise, you need a macro like this:
(DEFUN CV3 (/ p1 p2 p3 p4 x1 x2 x3 y1 y2 y3 adj dx dy opp om ang rad arc ark) ; Dimension END to END along an ark
(SetVar "CMDECHO" 0)
(Setq om (GetVar "OSMODE"))
(COMMAND "Osnap" "END")
(setq p1 (getpoint "\nSnap to first END: ")
p2 (getpoint "\nSnap to second END: ")
)
(COMMAND "Osnap" "CEN")
(setq p4 (getpoint "\nPick a point on the arc: "))
(COMMAND "Osnap" "NON")
(setq p3 (getpoint "\nPoint to dimension location: ")
x1 (- (car p1) (car p4))
y1 (- (cadr p1) (cadr p4))
x2 (- (car p2) (car p4))
y2 (- (cadr p2) (cadr p4))
x3 ( / ( + x2 x1 ) 2.0000 )
y3 ( / ( + y2 y1 ) 2.0000 )
adj ( sqrt ( + ( * x3 x3 ) ( * y3 y3 )))
dx ( - x3 x2 )
dy ( - y3 y2 )
opp ( sqrt ( + ( * dx dx ) ( * dy dy )))
ang ( atan ( / opp adj ))
rad ( getvar "Userr2")
arc ( * rad ang 2.0000 )
ark (rtos arc)
)
(COMMAND "DIM1" "ANG" "" P4 P1 P2 P3 ARK P3)
(COMMAND "DIM1" "HOM" "L" "")
(COMMAND "DIM1" "TE" "L" PAUSE)
(SetVar "OSMODE" om)
(SetVar "CMDECHO" 0)
(princ)
)

 

[lpseifert]

Here's a lisp routine to dimension the length of an arc. Can't be used in LT though.

;Arc dimension    (^v^) CAD Studio, [URL unfurl="true"]http://www.cadstudio.cz[/URL]

(defun C:DIMARC ( / pt1 pt2 cen a1 a2 D1 D2 p r oldOs)
 (setq oldOs (getvar "OSMODE"))
 (prompt "Pick 2 points on an arc - ")
 (setvar "OSMODE" 512)
 (while (not cen)
  (setq	pt1 (getpoint "1st pt: ")
	cen (osnap pt1 "_CEN")
  )
  (if (not cen) (alert "Doesn't lie on an arc, retry")
		(setq pt2 (getpoint cen " 2nd pt: ")))
 );while

 (setvar "OSMODE" 0)
 (setq a1 (angle cen pt1) a2 (angle cen pt2) ad (abs (- a2 a1))
	r (distance pt1 cen)
	D1 (* r ad)
	D2 (* r (- (* 2 pi) ad))
 )
 (prompt (strcat "\nArc length: " (rtos D1) ",   complementar arc: " (rtos D2))) 

 (command "_DIMANGULAR" "" cen pt1 pt2 "_T" (rtos D1) pause)

 (setvar "OSMODE" oldOs)
 (prin1)
)

(princ "\nDIMARC command loaded.")
(princ)

____________________
Acad2005, Terramodel

 

[OZZY84]

modify -> lengthen

select line or arc, reports length

experiment with command options

hope this helps

Intel P4 3.0 GHZ
512 DDRAM
Win 2000 Pro
Autocad 14, 2002 with EP 2.3.1

 

[chicopee]

If the line is continuous do a LIST command, pick the curve with the cursor and do a history check of that line. Length will be indicated.