Improving filet edge

Often if I filet an edge that is intersecting with another filet edge, Rhino does not seem to find the intersecting curve properly:

In the picture above I am doing a Block edit. the motor mount needs to be trimmed to allow easier wrench access.
Original Block was filleted all around. I did two wire cuts then I am trying to Filet the edges to remove sharp corners. As shown on the screen shot, Rhino extends the surfaces beyond the object as if it did not find an intersection… I see this happening very often when two filet intersect.

Is there any work around or attempt to improve the behavior?

Hello - can you please post a file with the object prior to adding the new, incorrect fillets?


Here is the link to the file:

@jean.marc - thanks, I have it, but that is a public link - is that OK here? Looks like a full project that might not be meant for the public.


not really but if you have it uploaded I can disable the link. File was to big and I did not recall your upload site.

PS: Problem also happens with chamfer. Sometimes If I trick the Diameter or distance it works.
But I really would like to spend less time fixing edge issues and concentrate on design.

Hi Jean-Marc - as is the part is filleted where the untrimmed ones are in your image - what fillets are you trying to add here?

There is an existing chamfer all the way around the top edge.


Yes on the original solid, I have a 10 mm corner edge(x2) and then a 0.5 mm chamfer all around.
First I did make two Wire cut to the part her re creating step for first Wire cut:

This creates a sharp edge I want to round at 10 mm:
This is what I get:

The lathe would leave a burr but not that long:laughing:

Got it… thanks. I am not surprised that Filletdge did not know what to do, with that chamfer there. Let me see what I can do.
If you fillets all three edges (including the little chamfer edges) it works but might not be what you expected or wanted here:


Otherwise, you’ll have to go at it at the surface-to-surface level.


yes not what I want. In addition once the edge is rounded I want to chamfer the top and bottom edges as per original.
Is there a way to undo the Chamfer before the wire cut then reapply filet and chamfer ?

Hi Jean-Marc- it is pretty quick to use surface tools.

FilletSrf and extend a little to make it too tall:

then ChamferSrf:

and a little trimming and joining.

Flex Adapter_PG.3dm (845.9 KB)


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Hi Pascal and Jean Marc,

I have a similar problem using filetSRF on these intersecting trimmed surfaces. The fillets do not seem to recognise each other as boundaries. They will therefore not trim to each other. The images show trimmed surfaces that do not align very well, but this is also happening on edges that do align. It seems to be the change of direction. Perhaps I need to create better surfaces in the first place? I’d like to do it as one continuous filet ideally.


example_filet.3dm (590.4 KB)

you can use dupedge to have a curve, then pipe and split the surfaces with it. later you can use sweep2 or blendsrf

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thanks @DiegoKrause I’ll try that

here you have some examples:

you make it look so easy. I get some crazy errors. this one looks nice :slight_smile:

use RebuildCrvNonUniform to have a smooth curve, then pipe it