topic Re: Is there a way to change an arc to a circle without first deleting it? in Inventor Forum

Is there a way to change an arc to a circle without first deleting it?

karthur1 — Tue, 19 Mar 2019 22:03:02 GMT

In a part sketch, I originally had an arc with tangent lines. Later in the design, the lines were removed and now the arc needs to be closed to be a circle. I know that can delete the arc and just draw in a circle, but there is geometry downstream that relies on this feature, so in hopes in saving the associative geometry, I would rather not do that.

What seems intuitive is to just apply a coincident constraint to close the arc, but when I try to snap the two ends together, I get an error.

Is there a hidden trick to dong this?

Thanks

Re: Is there a way to change an arc to a circle without first deleting it?

jtylerbc — Tue, 19 Mar 2019 22:21:04 GMT

I don't think you can. But having run into this before myself on occasion, I'm hoping I'm wrong and someone else will post a viable solution.

Re: Is there a way to change an arc to a circle without first deleting it?

Cadmanto — Tue, 19 Mar 2019 23:22:23 GMT

Yes, I just did it.

I started a new sketch, created an arc and see below;

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Re: Is there a way to change an arc to a circle without first deleting it?

johnsonshiue — Wed, 20 Mar 2019 00:26:02 GMT

Hi Kirk,

Indeed, like John mentioned here, it cannot be done. An arc and a circle in 2D Sketch are two distinct definitions. They are not interchangeable unfortunately. Do you mind elaborating the need to have the ability?

Many thanks!

Re: Is there a way to change an arc to a circle without first deleting it?

JDMather — Wed, 20 Mar 2019 07:51:04 GMT

@karthur1 wrote:

....but there is geometry downstream that relies on this feature, so in hopes in saving the associative geometry, ...
I would change the arc to Construction and sketch overtop of it.

Re: Is there a way to change an arc to a circle without first deleting it?

Sergio.D.Suárez — Wed, 20 Mar 2019 08:24:32 GMT

Excellent!! works!! @Cadmanto thanks for sharing such knowledge, has taught me a solution to a problem that once gave me a headache

Re: Is there a way to change an arc to a circle without first deleting it?

karthur1 — Wed, 20 Mar 2019 12:32:58 GMT

Scott,

That will work. In my case I already had a construction line thru the center, so just extending the ends of the arc to the line closed the circle. The solution that I came up with was to just draw another arc from the end points of the exisiting arc.

And then apply an equal constraint between them.

That also closed the loop and I was able to keep my existing geometry.

Thanks for the idea.

Kirk

Re: Is there a way to change an arc to a circle without first deleting it?

karthur1 — Wed, 20 Mar 2019 12:43:11 GMT

@johnsonshiue wrote:

Hi Kirk,

Indeed, like John mentioned here, it cannot be done. An arc and a circle in 2D Sketch are two distinct definitions. They are not interchangeable unfortunately. Do you mind elaborating the need to have the ability?

Many thanks!

Johnson,

The reason I need the ability is so I can close the loop and use the sketch geometry for a feature (extruded, cut). This part is used as a master in a skeletal design, so deleting the arc would affect several other pieces that use this geometry.

Thanks,

Kirk

Re: Is there a way to change an arc to a circle without first deleting it?

jtylerbc — Wed, 20 Mar 2019 13:38:23 GMT

@Cadmanto , that's very helpful. I swear I've tried something like that before and couldn't get it to work, but it certainly seems to work now.