Problem using fillet edge or workflow around it

Hi i have a question about the fillet edge, or workflow related.

I’m relative new at using Rhino v5.3.2 Mac, so if i’m asking something obvious i’m sorry :wink:

I have tried to look at diffrend guids and tried diffrend approach to the problem but im not 100% happy whit the resoult. so my question is what or where im doing it wrong.
or whot i can do to improwe my workflow?

I have three organic shaped rings that needs to have a fillet in the joint.ring fillet.3dm (7.2 MB)

First try. “filletEdge” 0.5 not working. 0.5 prefered radius but i have tried all the way down to 0.1 to see if that could help the problem. also tried to make the model 200% (don’t know if this makes any difference at all)

Secont try. Made a “pipe ø1” in the joint and used it to trimme the surface then used “blendSrf” this have a reasonable surface but there are still meany smal kinkes and mistakes.

Third try. using “offsetCrvOnSrf” to make a guid 0.25mm from the joint on both sides then using “sweep2” to fill the gap. this gives the less errors and naket edges. but its not very time effectively to do and the end surface is a bit edgy.

One thing I would suggest is to save all of your filleting to the end. Don’t fillet the top and bottom edges of the rings first. Boolean or split and join them all first, then try filleting.

fillet test.3dm (582.7 KB)

Hej dmoyes thanks for your answer. I tried you advise on my model and it doesn’t help! then i recreated the one you made and tried on that. and here i can get a smooth transition as you.

The only difference i can see is that my circules have a small angle in opposite
direktions when looking at the cross-section

So don’t know if you have another suggestion, i need a minimum three degree angle on the sides

same technique on tapered rings. I made two concentric circles on the construction plane, turned them into a surface, then extruded the surface with a taper. Copy the ring, rotate 180, move the top ring into postion, boolean union, fillet edges all at once.tapered rings.3dm (602.3 KB)

Yes that taper in your rings is partially the problem.

It looks like you sized the fillets on the rings so that the fillets don’t overlap. That would have worked if the rings had no taper, but the taper causes filletedge to fail

You can make all the fillets using FilletSrf. The problem is where the rings meet at a sharp angle the fillet will collapse in on itself, The area that the fillet collapses can be fixed up with a blendsrf or sweep2. Here are just the fillets
that you can import into your file,
ring fillets.3dm (104.0 KB)

You can also make the fillets on your rings smaller so that there is room for another fillet in between, like dmoyes did

Make the fillets on the rings ,4mm and filletedge should be able to figure out where the fillets go.

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Hej Jim thanks for your answer.

I can not get FilletSrf to work it brakes the model in a wird way or failes and won’t build at all. but it’s probably my lack of knowledge in using the skill so i have to look in to this.

I can get it to build with FilletEdge when giving it the small room in between. even with 0.06 gab so this is what ill work with.

Dmoyes and Jim thanks for the help :slight_smile:

Yes, filletSrf can be difficult to use, but it does work. It will make all the fillets all the way around that can then be used to trim and then will join.

Since all the surfaces being filleted are tangent you need to use the extend=no option in filletSrf. Then where the corners each fillet lands tells you which 2 surfaces are next and where to make the 2 mouse clicks for the next connecting fillet. If you find that you have gaps between fillets look closely you will see that you didn’t follow the simple recipe for which surfaces to pick next and you will discover you missed picking 2 surfaces.

Of course it would be very easy for Rhino to have an option to make all the connecting fillets for tangent surfaces so that the user would just define one fillet in a loop such as this and the software would create all the connecting fillets by following the same recipe which tells you where to make each subsequent mouse pick.

Don’t know enough (anything) about 3D CAD development to vouch for the veracity of this statement. However, I would say that if such is even close to accurate, it would a value add to get this ‘feature’ added to “the pile”, if possible.

Is someone in ‘the know’ able to comment, please?

Thank you!

Found this on the Rhino Hidden Secrets Wiki. It might be helpful:

14. Filleting edges of a solid

Make the unfilleted shape and get all the surfaces to join together to make a closed polysurface. Check that it is closed with Rhino > Edit > ObjectProperties > Object > Details (button). You can also check using the ShowEdges command in the NakedEdges mode. You can practice all this with a simple Box.

Make the largest-radius fillets first with the FilletEdge command, selecting all the adjacent edges you want filleted at that radius in the same operation. Fill any holes the fillet-making creates. This takes planning.

Make the smaller-radius fillets, including all the adjacent edges that need rounding (possibly including some edges made by the larger-radius filleting). Check for closure again.

You can also fillet all the edges of a solid at once with the same radius by starting the command and window selecting the object.


If I have to Fillet/Blend edges I first try to build original surfaces as single surfaces -> merge profile curves into closed curve, fillet that curve and then perform sweep/extrusion… to get surface. I created three rings by using that approach and uniion them. Then you use fillet/blend edges or Sweep2/NetworkSrf comand to get “rounded” edges.
ring fillet RG.3dm (1.2 MB)