Polygon star has a hole in the middle

I’m trying to draw a sheriff’s badge. I created this star in the centre of the badge with the polygon star. After a quick shaved render it became obvious there was a hole in the centre of the star. As the star has a curved surface, is there a way to plug the hole?``

Sherif Badge

It would be more helpful if you uploaded the model (e.g. by dragging it onto the text entry field when you are writing a message here) but I guess you can just extract that top surface, untrim the hole and join with the rest.

I suspect that your surface was a surface of revolution starting with an arc and that the arc endpoint did not touch the axis of revolution… hence the hole. Probably best to just verify your input curve, if that’s the case, fix it by adjusting the curve so its end lies on the revolve axis, and re-revolve the surface…


Sorry about the delay in getting back to the form, big weekend.
US Marshall badge.3dm (130.1 KB)

I suspect Helvetosaur is correct. The original drawing was all based on a rail revolve which created the hole.

I had a think about it last night and came up with a new approach. I created a spherical primitive with the correct diameter. I then used the ‘Polygon start tool’ with the correct dimensions and Extruded up through the primitive. I used a Boolean difference to get rid of the spherical primitive.

I now have a new star with a surface without a hole. Next step, I extruded Star to the correct height and I now have a new star without a hole.

Badge without hole.3dm (237.1 KB)

thank goodness there are more ways to skin a cat in rhino. I can’t wait for a decent render application that will work with the Mac version of Rhino.