Fillet edge problem


no matter which tolerance I use, fillet edge command creates naked edges on the bottom side.
Is this solvable? Thanks!
Sample file:Fillet edge problem.3dm(425.1 KB)
Sample image:


Don’t know if this answer you, but:
the fillet edge gives you this problem because at the bottom the radius always become 0 due to the tangency on the lower edge (the base circle).
Rhino doesn’t handle radius zero.

I know it’s boring, but you have to fix the hole by hand, trim and sweep2.


Hi Skysurfer,
thanks for your answer,
I’m aware of that, though I hope that this will also be solved.


When you decide to give us the tools fillet more robust and convincing?
With Rhino 5 improvements are there, Rhino 4 was a little lacking, but still not enough, we all hope in Rhino 6!


Hi Violine
In the attache files .3dm the fillet is OK V5 SR5
Ciao Vittorio
FilletEdge_OK_2.3dm(90.9 KB)

FilletEdge_OK.3dm(51.0 KB)


You man, always a step ahead!
I still have the SR4!
Running to update mine version.

Grazie Vittorio.

(Brian James) #7

Thanks for this example file violine. In your model with this exact geometry and radius settings, I can still produce the naked edges you point out. I’ve filed this as RH-20643. This report is not publicly visible at this time.

Thanks for taking the time to make this sample. Development will look at supporting this case.


Hi Vittorio,
with your model with different rail curvature I’m able to do the edge fillet also in V5 SR4.
The difference is in the rail curve inclination, which in my case is an constant arc curve.
I’d like to be able to use also the Shell command for the top surface.
Thanks for your sample Vittorio.
Thank you Brian.


here I found another problem, it should work because it is a rather simple form, is it possible to solve?
Sample file:Fillet edge problem2.3dm(333.1 KB)
Sample image:

(Pascal Golay) #10

Hi Violine- that is a problem still, yes-- four converging edges are not handled well as a solid operation when the edges are not all either convex or concave.( i.e. the inner mitered edge at each corner is concave and the other three are convex) You need to revert to Rhino’s surface modeling tools- explode, untrim, intersect retrim etc.



More samples for FilletEdge and ChamferEdge errors:
Fillet and ChamferEdge error.3dm(146.3 KB)


Hello Pascal, here are two other examples in which the fillet and chamfer fail. We must also work to resolve this type of situation, if not drag these issues in Rhino 6 and this is not good for the reputation of the program!



what’s the round one supposed to look like?


Hi Jeff,
yes, seems to work on this sample when you explode surfaces and use FilletSrf command.
Good to know this, thanks!
For closed polysurfaces it is a problem to solve.


actually, filletSrf worked on the inside bend but fails on the outer… i had to draw that a different way.

it will work until you want to fillet the same radius as the pipe.
(tried a try a 1unit radius pipe then filletSrf at 1 unit… it will fail… .999 and less will work though)

regardless, when these fillets and whatnot fail-- sure, report them to mcneel but i also think it’s worthwhile to figure out how to draw them using other tools


Yeah I noticed this problem with a same as pipe FilletSrf radius, thanks!
I agree with you, but again, these are pretty simple forms where things should work because this software is used by people with different skill levels.


Software such as Rhino should solve problems without this kind of connections, I would say, simple.
We’re not talking connections generate complex, but simple cases. I hope to be better addressed the issues of “fillet” in the next version, otherwise we drag always the same problems from version to version.


It should solve all that does not work currently, marking the main points and gradually deal with the decision, otherwise the new version will meet the same problems exist in Rhino 5.
Is a complicated job, but doable if done methodically and order.
Many cases in which it fails Rhino have been reported, and now it is up to developers to try to solve the various problems: Boolean, fillet, shelling and 2D should be the priorities in my opinion; now many CAD software are a step forward in this direction. Even MOI 3D, for example, is evolving in a strong and effective, and the gap is narrowing with Rhino.