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

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Message 1 of 6
royDMYAP
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AutoCAD - Converting segmented arc made of straight lines to an arc or circle

royDMYAP
Contributor
Contributor

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):

 

royDMYAP_0-1666684066843.png

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 ]

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

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):

 

royDMYAP_0-1666684066843.png

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 ]

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5 REPLIES 5
Message 2 of 6
imadHabash
in reply to: royDMYAP

imadHabash
Mentor
Mentor

Hi,

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

My direct answer is " NO " .. sorry .

Imad Habash

EESignature

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Hi,

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

My direct answer is " NO " .. sorry .

Imad Habash

EESignature

Message 3 of 6
Kent1Cooper
in reply to: royDMYAP

Kent1Cooper
Consultant
Consultant

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.

Kent Cooper, AIA
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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.

Kent Cooper, AIA
Message 4 of 6
leeminardi
in reply to: royDMYAP

leeminardi
Mentor
Mentor

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.

leeminardi_0-1666710183861.png

 

leeminardi_1-1666710250983.png

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.

lee.minardi
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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.

leeminardi_0-1666710183861.png

 

leeminardi_1-1666710250983.png

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.

lee.minardi
Message 5 of 6
RobDraw
in reply to: royDMYAP

RobDraw
Mentor
Mentor

@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.


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.


Rob

Drafting is a breeze and Revit doesn't always work the way you think it should.
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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.


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.


Rob

Drafting is a breeze and Revit doesn't always work the way you think it should.
Message 6 of 6
schulz8NPAP
in reply to: royDMYAP

schulz8NPAP
Advocate
Advocate

Can you please upload an example.

(I use another approach using SPLINES)

Regards

Jochen

www.black-cad.de

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Can you please upload an example.

(I use another approach using SPLINES)

Regards

Jochen

www.black-cad.de

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