Hey. I’m fairly new to rhino, and was wondering if anyone can help me troubleshoot this.
I created a solid by using either Extrude along rail or sweep to curve. (I forget at this point.)
I used a curved line, which reaches the center point of a circle. And extruded it round the circle to make a cylinder with a beveled edge.
I can boolean difference the shape I got. But I cannot union it to another shape.
I get the error “Intersection curve ends at a non-manifold edge.”
I have two questions:
Can I fix this?
Is there a better way to do this?
jeremy5
July 12, 2026, 4:56pm
2
Hi John,
I suspect your curve didn’t just reach the centre of your circle but overshot it by a tiny amount.
But we can only guess unless you post a model containing your two objects…
Regards
How would I go about posting a model?
Also, if I’ve cut the middle out (where the overlap should be?) would that have fixed it?
jeremy5
July 12, 2026, 5:38pm
4
You can click here:
and browse to find your .3dm file.
If you have a large file it is helpful to select the relevant elements and save them into a new file and post that rather than the whole kit and caboodle.
If you have cut the middle out and are getting the error afterwards the problem will be something else.
jeremy5
July 12, 2026, 6:32pm
6
Hi John,
So I understand you correctly, you want to union the ring with the cylinder?
Only, when I do that with the model you posted it works fine:
(I moved the unioned object upward to separate it visually from the original components)
Thats so weird!
I have re-opened rhino and it is indeed just working now.
I spent two hours trying to fix this earlier.
Go figure.
Oh and thanks so much for taking a look! I appreciate it.
Tom_P
July 12, 2026, 7:11pm
9
solved?
