Circle size change when rotating
When I rotate a perfect circle, the size changes up to .004”. A 15”x15” circle, when rotated 17.184° becomes a 15.004”x15.004” circle. I know it may sound trivial, but I’m creating technical drawings that have to be accurate to the ten thousandths of an inch.
I am happy to share that we have fixed this bug in our latest release – 24.3.0 which is available worldwide now.
Going forward, our goal is to fix as many top User-Voice bugs as possible and as frequently as possible. Given the nature of the fixes, some of the bugs will take a longer time to fix, but we are on it.
You can update to the latest release using Creative Cloud desktop App: https://helpx.adobe.com/in/creative-cloud/help/creative-cloud-updates.html
Thank you for all the feedback. Keep it coming!
Doug Roberts commented
For Mandi (and future readers),
This 'fix', such as it is, only applies to live shape ellipses. Once expanded, circles will show their 'true' size.
Is it at all possible that the bug got reintroduce in a later version? Or perhaps never corrected for a compound shape? I am on v 26.0.3 and I am having the same issue. To be fair, I do have a group of two overlapping identically sized circles of 240x240px, one of which has parts removed to create a wave effect. The group does have a dimension of 240x240 until I rotate and then things get wonky on a small scale that varies depending upon the rotation (eg. 240.0299x 240.0578px).
Doug Roberts commented
This issue is listed as fixed in the notes for 24.3.
What has actually happened to fix this? Has the nature of an ellipse in Illustrator changed?
No: just the bounding box. Create a circle of, say 1000 px. Rotate it 22.5°. With it selected, zoom in on the middle of one of the sides. The bounding box slightly undercuts the circle as drawn! So the bounding box says 1000 px at any rotation, but the actual ellipse is the same as previous versions of Illustrator. What exactly does this fix? Doesn't this just confuse the issue more?
And yes, 'ten thousandths of an inch'?
Use CAD programs and not illustrating one.
Circles, drawn with bezier curve with for points is not a real circle, but an approximation, regardless of which program you are using. It's just how the math works. You can read more about it here:
Here's the part you could be interested in:
"In fact, the precision of a cubic curve at a quarter circle is considered "good enough" by so many people that it's generally considered "just fine" to use four cubic Bézier curves to fake a full circle when no circle primitives are available; generally, people won't notice that it's not a real circle unless you also happen to overlay an actual circle, so that the difference becomes obvious."
Don't be sad. Draw circles with more points — you can use AstuteGraphics plugin for that or scripts.