Trouble with FilletEdge

[hugo2 (hugo)]

Good Morning everyone!

I was wondering if poeple would agree to say that filleting edges in Rhino could be sometime quite tricky and annoying?

For instance I notices that when I try to fillet multipes edges belonging to different surfaces (some ar planar and some are not) the fillet almost always fails..

I tried to make it in 2 steps, it worked better but I got this:

Similarely, this king of fillet would always fail:

Whereas here , it worked just fine between these 3 surfaces :

Does filleting became less rigid in Rhino 8 ?

Cheers!!

[Lagom]

Without a 3D file, it is hard to say what exactly the problem is. In general, FilletSrf works very well, when you stop thinking of “edges”, because filleting is something that happens between surfaces, where usually the latter is already the clue to how to go about it.

[hugo2 (hugo)]

fillet-issue.3dm (6.9 MB)

Dear Lagom, here is my 3D file if you want to have a look

[Tom_P]

you will get much nicer result, if you just see / construct the surfaces you expect from fillet.
in this case the cone-like surface can be easily constructed by a loft (start/end tangent) between 2 helper surfaces.
the initial construction already has to consider the final fillets:

check the file and see that the fillet starts at 3 mm higher then initially and the base rectangle is smaller…

fillet-issue_tp_00.3dm (3.0 MB)

EDIT:
with some limitations this result is also possible with filletEdge - but this is more a prove of concept, not a recommended way to do it:

define the geometry with above geometrically background.
_splitEdge the vertical edges at the positions where R31 starts to blend to R1.5 (at local Z=3)
_filletEdge with additional handels as in the screenshot
_filletEdge partially fails, - repair it: explode, trim, join
_filletEdge R3
_filletEdge R1

[hugo2 (hugo)]

I understand this is indeed probably the best practice I never noticed this possibility with the loft command thanks a lot !

[Lagom]

So, first lay off Join. You only need to join a fully completed part. Then lay off the FilletEdge. In a 3D surface model, always think about surfaces, not “edges”. See below, with translucent shading, so you can see the fillets and original surfaces. With FilletSrf, simply clicking on the surface pairs, between which a fillet shall be built, will give you the result you’re after. Rhino’s FilletSrf just works.