Problems with Fillet Edges Command in Rhino 6 (Mac Version)

I’m learning Rhino to make jewelry models and I’m having issues with the Fillet Edges command in the solid tools menu. I’ve noticed it’s mostly after creating a closed solid polysurface from joined surfaces or open poly surfaces. I join them and check that it is a closed solid polysurface. But when I fillet the edges it creates gaps on the edges which makes it become an open polysurface. I’ve tried playing with the settings of the fillet edges command from Rolling ball to Distance from Rails etc. but it still creates gaps. Also if someone can briefly explain what the difference is between these options (rolling ball etc. I would be grateful!) I then use the Show Naked Edges command to see where the gaps are located. In one case I repaired it by creating a surface from the edges of the gap and then joining them to the open polysurface and it worked to create a closed solid again. But I’m sure there must be a better way to achieve this. Can someone help me. Thank you!

Can you post a small example of where it goes wrong? FilletEdge is reliable in a lot of cases, but there are also a lot of cases where it can fail either lightly, leaving open edges, or catastrophically… leaving a mess.

If FilletEdge doesn’t work in a particular case, than FilletSrf pretty much always will - but it needs some experience in how to use it and a bit more ‘manual’ labor.


Here are the screenshots of the process of the fillet edge command. I created this ring by first making curves then using the loft command to make the surfaces. I then joined the surfaces together to make a closed solid polysurface. Maybe something in my process was off which is why the edges keep breaking…I’ve also seen lots of people mention tolerances on this forum which I don’t really get. Maybe that’s an issue too.

Thanks for your help! J

One more of the whole ring. Maybe it’s something about the design…

Welcome @jentaylor77,

In this case, you can use the MergeEdge command to join two opposing naked edges.
Filleting and chamfering are often tedious processes. :wink:

I believe you meant JoinEdge. MergeEdge is for merging continuous edges of surfaces that might have gotten split for some reason (by having been joined to something else at one time, for example).

However, that being said, JoinEdge is not to be used lightly, it is a crutch for trying to cover up something else that is wrong by locally overriding the file tolerance. Best to find out why the problem happened in the first place and fix that. Let me look at your file… Oh, wait, you only posted pictures I can see. Can you post the actual Rhino file?

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Hey, I tried that but it says the the “edge is already merged” in the command line…What am I missing here.

Curved Ring.3dm (3.9 MB)

Yes here it is! Just out of curiosity I’m assuming JoinEdge work only if the polysurface was exploded right? Thanks so much.

No, it should work even with joined polysurfaces. However, don’t do that.

The file already has the fillets, but I was able to remove them and untrim the surfaces to get back to the unfilleted condition. The problem is on the bottom edge, your edge/surface isn’t continuous - it has about a 1.5° tangency break. Probably due to your original curves not being clean in that spot.

I turned on curvature graph on that edge and you can see the break clearly.

So you probably should go back to your original generating curves and fix those then try re-making the surfaces. Fillets are pretty sensitive to small tangency problems.

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I think I get it…Will check it out. Thanks again!