draw an arc given its length

[effedieffedi]

Hello everyone,

I have to design in autocad a circle arc for example of radius 60, but the length of the arc (and not of the rope) must be 100.

I can't do anything!
someone can help me please!!!

Thank you.

 

[PlannerRoad]

draws the arc and then uses the extended command with total option inserting the length you want for the arc.
autocad does not allow the design of an arc given its length.

 

[Giuseppe Mauro]

Look, it's trivial. It's longer to say than to.

draws a circle with radius 60. breaks the circle at a point something, pulling away a small piece (this serves to make the circle a bow)
From the measure command (measure in English), select the arc and type the length you want.
along the arc, to the extent established, will be put a point (or more than one if the measure enters more than once).
eliminates the arc part from the point on.

instead of circle and then break, you can draw 3 long ray segments from a common point, in 3 arbitrary directions. after the arc command and click the ends of the 3 segments.
after this the measure of the arc follows the same procedure

planner procedure is effective, faster than mine

 

[paolino]

otherwise draw a radius arc you want and with x angle:

x = (180° * arc length) / (pigreco * radius)

 

[PlannerRoad]

this lisp allows you to create an arc through length and radius:

;written by: derek 'maverick' beals
;version: a
;date: 9-26-05
;description: this lisp routine draws an arc at given length & radius

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;non-standard lisp functions

(defun rtd (r) ; radians to degrees
(/ (* r 180.0) pi))

(defun dtr (d) ; degrees to radians
(/ (* d pi) 180.0))

(defun tan (a) ; tangent of variable (a) in radians
(/ (sin a) (cos a)))

(defun sqr (a) (* a a)) ; squares the variable (a)

(defun fixx (realnum) ; rounds the variable (realnum) to the next highest whole integer (opposite of the "fix" function)
(if (> realnum (+ (fix realnum) 0))
(setq realnum (1+ (fix realnum)))
(setq realnum (fix realnum))
)
realnum
)

;(setq variable (ssget)) - allows multiple picks in lisp

;(setq os (getvar "osmode"))...(setvar "osmode" os) - gets current o-snap settings @ front of lisp, then reestablishes them at the end

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;lisp programming starts here


(setq leng (getdist "\nenter length of arc: ")
rad (getdist "\nenter radius of arc: ")
cen (getpoint "\npick center point of arc: ")
ang (/ leng rad)
ang1 (/ (- pi ang) 2.0)
ang2 (/ (+ pi ang) 2.0)
arc (entmake (list
(cons 0 "arc")
(cons 10 cen)
(cons 40 rad)
(cons 50 ang1)
(cons 51 ang2)))
)
(princ)

download

 

[GP.]

In fact knowing length and radius is solved with normal commands (total extension the fastest), instead having length, starting point and final point, is absolutely impossible with autocad "nudo".

 

[PlannerRoad]

you could also solve with the option 'horse (always by length and radius), as recommended in this post pressure:r2d(l/r) Entering that value in the corner.

 

[effedieffedi]

you have been magnificent and celerissimi!! !

you had solved my problem...

:finger:

:smile: Thank you very much to all!

 

[piero1967]

Hello everyone
gp, don't know what you mean by naked autocad, without the help of other applications?
I did a macro (thanks to the collaboration of many of you, because they are just at the first weapons with vba having started from a week) to make a fine start arch and arc length, but also uses excel.
Hi.

 

[GP.]

Hello everyone
gp, don't know what you mean by naked autocad, without the help of other applications?
I did a macro (thanks to the collaboration of many of you, because they are just at the first weapons with vba having started from a week) to make a fine start arch and arc length, but also uses excel.
Hi.

Coastal steward solo with autocad commands, without using lisp, vba, etc.
if your macro is This is what discussion, however, is related to other types of data (start, end, angle).
having arc and rope, i.e. length and starting/final points, There is no direct formula for the calculation of the radius.:smile: