topic Re: How to draw an arc at a certain radius and length? in AutoCAD Forum

How to draw an arc at a certain radius and length?

russel — Wed, 25 Oct 2017 17:39:49 GMT

how do you draw an arc at a certain length and radius?

for example I want to draw an arc at 149'-9" long at an 2793.25' radius.

Re: How to draw an arc at a certain radius and length?

Kent1Cooper — Wed, 25 Oct 2017 18:27:25 GMT

I don't think you can do that directly with standard AutoCAD Arc-command options. I think you'll need to use a routine such as [just one example] ArcLength.lsp, available here.

Or, in two steps, you can draw an Arc at the desired radius, of any length [or a Circle, and Break part of it out to make an Arc], and use LENGTHEN and its Total option to make it the length you want.

Re: How to draw an arc at a certain radius and length?

TheCADnoob — Wed, 25 Oct 2017 19:24:10 GMT

@Kent1Cooper solution of lengthening you arc sounds best, but i created this video so i figured id share it any way.

The formula i used is

c=(360∙L)/(2∙π∙r)

Re: How to draw an arc at a certain radius and length?

russel — Wed, 25 Oct 2017 19:29:57 GMT

that helps thanks. a little more work than I wanted to do but still works.

would be great if they had a feature where you could type in the radius you wanted along with the length you wanted and hit enter.

Re: How to draw an arc at a certain radius and length?

TheCADnoob — Wed, 25 Oct 2017 19:45:10 GMT

@Kent1Cooper's suggestion is much easier

Re: How to draw an arc at a certain radius and length?

russel — Wed, 25 Oct 2017 19:47:16 GMT

that way is even easier, thanks for the help.

Re: How to draw an arc at a certain radius and length?

davidUB2V2 — Wed, 22 Jan 2020 18:25:20 GMT

Thank you for the help with this topic.

Re: How to draw an arc at a certain radius and length?

Anonymous — Wed, 14 Apr 2021 10:22:48 GMT

great answer (even if not yours)!
thanks for the instructional video

Re: How to draw an arc at a certain radius and length?

Charles_Shade — Tue, 21 Nov 2023 13:37:41 GMT

Nice

Re: How to draw an arc at a certain radius and length?

Des_R-Turner — Thu, 05 Dec 2024 14:03:30 GMT

Thank you. LENGTHEN and Total worked great for what I needed.