Rotating a outlined circle wobbles, why?

[rfranks]

Hi there I draw a perfect circle with an outline (say 20pt thick) and no fill. Then turn it into a graphic symbol with the registration point in the centre. Then make a keyframe. 30 frames later I make another keyframe after I've rotated the circle. Then tween the keyframes. Then when I play the animation the circle has a really wobbly rotation. Is there any reason why? I've never had this issue before in Flash or After Effects, etc.

I would attach my file here but I keep getting this forum error ( The attachment's rotation.fla content type (application/octet-stream) does not match its file extension and has been removed. )

Thanks in advance.

[n. tilcheff]

Hi mate,

Just use a file hosting service such as google drive and post a link to the file, please.

It should not be behaving like that.

[rfranks]

Yeah it's weird, I tried in Flash 12.0 too and it does the same thing. I've been using Flash for like 10 years and can't beleive I've never come across this before.

But does this work for you?

https://drive.google.com/open?id=1b3qUHPrKlgJfZ1JOPuF8IPdWCYbctBff

[n. tilcheff]

Wobbly here as well.

Tried in CC19.2.1 and CS6 - identical results.

Looks like the generated circle is not perfectly circular.

(There is a lot of rounding of values in the way Flash works - so this seems like one more such example.)

So if you need to do this kind of stuff you will have to layer things somehow to fake rotation and avoid the unpleasant effect, or mask the outer shape to hide the wobble.

[rfranks]

Ugh, well the masks worked, but man what a hassle.

I can't beleive I haven't come across that before.

Thanks for your help again.

[n. tilcheff]

You're most welcome, mate!

I'm surprised I had not noticed it before either, since I've made a bunch of rotating suns over the years, but always with beams and glow that reduces contrast, so that would have concealed the problem.

Good luck with your work!

[ClayUUID]

This most likely happens because Animate uses quadratic instead of cubic Bezier curves. Quadratic curves are faster to calculate, but provide less control over the shape of the curve. This is why, if you use the point select tool on a newly-drawn circle, you'll see that it requires eight control points to approximate a circle.

[kqskcm]

I also encountered the same problem