AutoCAD - Converting segmented arc made of straight lines to an arc or circle

[royDMYAP]

Hello, I have encountered the following problem:

Someone where I work used Civil3D to design multiple roundabouts, in order to work on the file in Autocad all the objects have been converted to polylines. But circles and arcs got digitized like the following example (in blue):

 

Is there an automated way to convert these polylines to arcs or circles? (fixing it manually is the last resort because there are many cases like the one shown in the file)

They are supposed to fit perfectly and not change the geometry at all because that's how they were created in the beginning. 

Thanks,

Roy.

[ The subject line of this post has been edited to include the product name by @handjonathan ]

[imadHabash]

Hi,

>> Is there an automated way to convert these polylines to arcs or circles?

My direct answer is " NO " .. sorry .

[Kent1Cooper]

It's not difficult to do manually.  CIRCLE, 3Point option, Osnap to a vertex somewhere near an end of the portion you want to convert, one somewhere near the middle, and one somewhere near the other end.   Do that to the various arc-form portions, maybe draw some LINEs TANgent to reversing-direction curves, and TRIM as needed.

[leeminardi]

Another approach to try is to use the polyline arc option.  When directly creating a polyline you cannot start with an arc segment so if the geometry you have starts with an arc just give the pline command and specify a point in space before the series of lines that you have.  For example, the red line below is a series of lines, the yellow is the start of the polyline.  After picking the first vertex enter A (arc) and you will be able to create a series of arcs that are tangent at their ends.

If the curve has a straight segment enter an L then an A again when you want an arc.

When you are done delete the beginning straight segment.

[RobDraw]

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@royDMYAP wrote:

Someone where I work used Civil3D to design multiple roundabouts, in order to work on the file in Autocad all the objects have been converted to polylines.

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How was this done? There may be a better way at this stage since what you did doesn't gives you something that you can't work with.

[schulz8NPAP]

Can you please upload an example.

(I use another approach using SPLINES)

Regards

Jochen

www.black-cad.de