Full Version: Fit Filleting Fails

Hello,
In my last project, I gained some experience in rounding lines at their points of contact.

But here, I can't round any of the corner points with Fit Fillet.
Why isn't it working, and is there a workaround?

I would really appreciate some help...

Cheers, Mala

Attachments:
fillet fail testing.3dm

Image Attachments:
fit fillet fails.png 

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Hi Mala, the main goal of curve filleting is to make a circular arc tangent between 2 existing curves.

Since a circular arc is a planar curve, it is expected that the 2 curves on either side of it should be planar curves and on the same plane.

Your case fails because it does not match that criteria, each of your curves is planar but they are each on their own separate plane, not both on a common plane.


Another method you could try would be to draw a sphere at the juncture between 2 curves, use the Edit > Trim command to cut the curves with the sphere so that there is some space opened up between them, then select the 2 ends and run Construct > Blend to put in a blend curve in that open space.

- Michael

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Simply brilliant !!!
- Ken -

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Thanks for the reply. And the lesson learned about failing at two different levels. Michael, I had already tried half of your solution before posting here. However, I was still using the `fitFillet` command. It worked sometimes and sometimes it didn't. I'll try the idea with the `blend` command later.

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That works very fine. Like Always. Thank you Michael, very much!

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Hi,
I'm having trouble with a new filleting.
Goal: The transition from the channels to the lens should be smooth/slightly rounded. Why am I unable to achieve this?

Attachments:
Linie orbit tresor moi forum.3dm

Image Attachments:
Screenshot 2026-01-26 100812.png 

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Hi mala, the initial problem is your model is made up of individual surfaces, you need to get it joined together so edges are shared instead of everything being separated.

- Michael

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Hi Mala, it looks like the separate surfaces problem is caused because your dome shape was an open surface instead of a closed solid when you did the boolean on it.

You should make the dome into a closed solid before doing the boolean. You can do that by selecting it and running the "Construct > Planar" command which will close off the bottom with a planar surface.

Additionally the cutting objects have a little gap in the middle area, they are also not solids. I closed those up by creating some lofts and joining those in.

- Michael

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Hi Mala, in the attached model I've fixed those problems.

So you should be able to open up the attached version, select these 22 edges:



Note don't forget this little one here:



Then you can apply a fillet:



It is helpful to refer to the "object type indicator" here to know if your
selected object is a finished solid or an open surface:



- Michael

Attachments:
Linie orbit tresor moi forum2.3dm

Image Attachments:
mala_fillet1.jpg  mala_fillet2.jpg  mala_fillet3.jpg  mala_fillet4.jpg 

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Hi Michael, thanks for eliminating the design flaws! I learned from them, replicated them in the design, and also added it to my personal MOI wiki.
Best Mala...

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