topic Re: Convert multiple polylines to arcs in AutoCAD Forum

Convert multiple polylines to arcs

jbear0000 — Tue, 22 May 2012 17:29:08 GMT

I have many segmented polylines that I need to turn into arcs. See the attached image for the method I use to create an arc from a single polyline. I need to do this to thousands of polylines. Does anyone know of a lisp that could do this? Or maybe some other method that can do many polylines at once?

Re: Convert multiple polylines to arcs

tcorey — Tue, 22 May 2012 18:24:38 GMT

Unfortunately, the aecccreatearcbybestfit command is not exposed to VisualLISP, so no luck there.

If you don't need the Best Fit functionality of that command, you can use Pedit, Multiple, Fit curve. That would do them all in one fell swoop. It won't be a single arc through the entire pline, but it will have tangent curve segments. Depending on your need for speed vs. your need to obtain a single best-fit curve, this might work as a solution. It would be fast, that's for sure.

Re: Convert multiple polylines to arcs

jbear0000 — Tue, 22 May 2012 20:35:11 GMT

I figured out a way to do it. First I use Pedit to fit a curve like tcorey suggested. Then I use mapclean and select Simplify Objects, set the tolerance to 1 and check the Create Arcs check box. This creates 2d polylines which can then be exploded to get arcs.

Re: Convert multiple polylines to arcs

controlsgirl — Thu, 02 May 2013 17:35:16 GMT

jbear, what is mapclean?

Re: Convert multiple polylines to arcs

troma — Thu, 02 May 2013 17:37:16 GMT

Type MAPCLEAN at the commandline.

Re: Convert multiple polylines to arcs

jbear0000 — Thu, 02 May 2013 17:37:38 GMT

Mapclean is a command, type it and mess around with it.

Re: Convert multiple polylines to arcs

Anonymous — Thu, 17 Oct 2019 19:12:26 GMT

Haha! I know this thread is like 6 years old, but came across it anyway trying to look for another option to do this. What I've found is that if you select multiple polylines, type "PE" for polyline edit, choose 'FIT' and hit enter, you'll end up with a curve line. Next, look in the PROPERTIES window under Misc and choose the dropdown option for 'Fit/Smooth.' Instead of 'Curve Fit' choose 'None.' Bam! Problem solved.

Re: Convert multiple polylines to arcs

khshohag69 — Tue, 28 Apr 2020 06:45:31 GMT

opps!
It works..
Thanks a lot.

Re: Convert multiple polylines to arcs

DomenicoViani — Sun, 23 Nov 2025 10:16:48 GMT

It is possible to choose the precision ? or the minimum lenght of the arcs ?