Fillet Edge goes wrong

Good evening Rhino Forum,

I’m working on a tutorial from the Rhino Level 1 Training. I want to fillett a hole that passes through the handle of the hammer.

On one side of the hole I can select a whole circle edge with one click and it fillets well, but on the other side I have to select two half circles to select the circle edge.

After I hit enter the result looks fishy and the what command shows an invalid polysurface.

Any idea what goes wrong?

Is it a good (valid) polysurface before fillet?

Yes, it is.

That’s normal, your hammer surface has a seam that crosses the hole, so the hole does not have one continuous edge, but rather two, one on either side of the split. The fillet should work OK anyway. There is probably something else wrong that is causing the object to turn invalid. Can you post the file in the “before filleting” condition?

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Dear Helvetosaur, unfortunately I can not because my 3 month trial version has expired, now I can’t safe.

But I noticed something fishy on the circular edge of the hole. After selecting the two semi circles, a tiny edge remains unselected. When I add this tiny edge to the selection and run the fillet command, it creates a different kind of mess.

Most likely your curves for the Sweep2 were not precise.

This is how they should look.

handle.3dm (250.2 KB)

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Yes, you are right Martin. I just noticed that the handle isn’t perfectly symmetrical. I also noticed that the hole-cut cylinder’s seam doesn’t line up with an isocurve near the seam and in the same spot where I have the tiny edges problem.

I aligned the seam to the isocurve and now I get a good result.

Working with a nice clean symmetrical handle would of course have been the way to go.

But even if the curve isn’t precise, shouldn’t Rhino be able to “suck it up” and produce a nice fillet?

I would rather make sure the input curves are symmetrical.

Yes, within tolerance…

It would be interesting to look at your file.