gluDisk shows broken line

I am trying to draw a ‘rope’ on the boundary of a field and have used gluDisk with a outer radius of 30 and an inner radius of 29.95. The circle is drawn in segments but is not a continuous circle and appears as a broken circle with various segments missing. To get a continuous circle by reducing the inner radius, the thickness has to become unrealistic before the circle is fully joined up.

Appreciate any thoughts on solving this - maybe I have to model my own rope section and draw a circle from these.

BTW, The key line of code I’m using is…
gluDisk( gRopeLine, 29.95, 30.00, 64, 4 );

A screenshot may be helpful, I can not visualize what your problem is.
Is face culling enabled? If it is, try to disable it.

Thanks for your suggestion. I disabled the face culling but can see no difference. Screen shot of the broken line is attached. All help is very much appreciated.

This is normal, as the width of your rope is less than one pixel (I would say half a pixel).
You will have to draw it as GL_LINE to guarantee at least one pixel wide line is visible.
You can also try a multisampled framebuffer, or glEnable(GL_POLYGON_SMOOTH); but that can become tricky.

I have now replaced the gluDisk with a GL_Line and this indeed works well. As an added bonus I can now get anti-aliasing working on the line so the result is now perfect!!

Great support - thank you and Happy New Year.