Creating a smooth circle (without dents)

OS (e.g. Win10): Apple Mac, Monterey (12.1)
PsychoPy version (e.g. 1.84.x): 2022.1.1
Standard Standalone? (y/n): y

I am trying to draw a circle that is transparent in the middle in Builder using the polygon component (I have set Fill Color to “None”). The circle needs to have a thick perimeter (so I have set Line Width to 20). When I draw the circle, it draws appropriately, but has four ‘dents’ in the corners (see attached screenshots). Is this a known problem?

If I draw a filled circle (with a thin line width), then the circle appears as normal, but my experiment needs the circle to be transparent in the middle. Any suggested workarounds most welcome.


This looks similar to one I came across a while ago. The solution there was to use two overlapping filled circles (the smaller one being the colour of the background).

Thanks for the suggestion! Unfortunately it’s not quite what I’m looking for (I was planning to use the outer circle as a mask for another stimulus that is non-circular, to give it circular edges) - but I suppose I might be able to make something like this work with multiple overlapping rings.

Silly me! I should have just used the aperture component all along. Problem solved :slight_smile:

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