Weird geometry when using the stroke tool on ellipses...

[UnmitigatedAudacity]

In every version of PS I've tried, whenever I draw an ellipse and then apply a wider stroke, the end result isn't the same shape as the ellipse.  Instead, the top, bottom, and sides.  seem to have some rounded angular sections where the same shape as the original ellipse should be. 

Look here: 

The ellipse is perfectly round, but the stroke seems to have parts where the edge is a straight line, then rounds into another straight line.  Is this unusual?  I've tried this and gotten the same results in PS CS5 through CC 2017.  I'd like to figure out how to do this without the imperfections because it's for an engraving that'll be used to make PVC patches. 

Many thanks,

George

[Mylenium]

You have to draw the "stroke" by adding and subtracting shapes and paths. You simply see the limits of the internal math with regards to how the stroke samples the path position.

Mylenium

[PECourtejoie]

Hello, Mylenium, is it the case in the other apps? if not, shouldn't something be done about that?

[davescm · Accepted solution]

Hi

It looks like you have applied the outer stroke using layer effects. As Mylenium said the maths on layer effects is limited and can result in the effect shown.

However if you apply the stroke directly in shapes then they are much smoother, but you are limited to just one stroke which can be "Inner, Centre or Outer".
So the solution is simple. Apply an inner stroke to the shape then duplicate the shape and apply the outer stroke in shape properties with no fill on the duplicate. You can see the difference below - the layer effect stroke is on the left, the shape stroke is on the right.

Dave