Is there a way to draw a perfect circle in illustrator CC?

[norinam]

Not sure if this is a recent bug or has always been there, but I cannot seem to draw a perfect circle using the ellipsis tool.

Shift > click + drag (doesn't work)

clicking artboard and setting width and height to equal values (doesn't work)

Found the following feature request that explains the issue a bit more.

The circles in Illustrator are flawed and here's why. – Adobe Illustrator Feedback

Is there a way to use the circle equation to create a circle without infinite anchor points?

(x−h)² + (y−k)² = r²

Or perhaps a way to manually draw a circle, although seemingly unlikely?

Re: Drawing a perfect circle

Or are other importable files like SVG capable of perfect circles that could be imported into illustrator?

<svg height="100" width="100">

  <circle cx="50" cy="50" r="40" stroke="black" stroke-width="1"/>

</svg>

I tried importing this SVG into illustrator, but it wasn't successful. Not sure if illustrator is converting the SVG or my method of import was incorrect.

Note: I have no idea if SVG files / definitions are capable of perfect circles, but if they are, then the above definition I believe would be a perfect circle.

[Kurt Gold]

It may sound a bit nitpicking, Jeff, but this isn't a real "perfect" circle either. It's another approximation.

It is very close and the deviations are pretty marginal, but they are still there, although Illustrator's Transform palette may not display them due to rounding differences.

[Jeff Witchel, ACI]

Noted!

Thanks Kurt!

[Kurt Gold]

Did you know that the assumed most precise sphere ever made in human history was manufactured by an optician (partially by hand)?

It was a project that tried to make a sphere that weighed exactly 1 kilogram (a "perfect" kilogram with a certain very marginal deviation).

But also this sphere isn't perfect according to its mathematical definition. Mathematical objects are concepts and in the end pure imagination. They cannot be perfectly produced as visible and tangible objects.

[DougKatz]

And here we see a (perfect) parallelism in mathematics and religion. Whodathunk such profundity would emerge in an Adobe Illustrator User to User Forum. Leave it to the inimitable Dr. Gold.

[norinam]

The BIPM - Avogadro project which was an attempt to precisely define the Kilogram - Wikipedia while the Planck constant - Wikipedia was instead adopted.

While we cannot create perfect circles or spheres, software can use their mathematical definitions. However, calculations always come at a performance cost depending on complexity, which is likely why Adobe chose to use bezier curves.

[Jeff Witchel, ACI]

You can also make what looks like a Stroked circle by rotating a 2 pt. X 2 pt. rectangle around a center point that's offset from the rectangle (the radius of the circle).

See screenshot attached.

Now that I think about it, either of these Rotate solutions can be done with a Transform Effect and then saved as a Graphic Style to be easily repeated.