Quick way to delete a fillet off a solid?

Depends on what type of fillets are needed . Fillets in Rhino are generally exactly circular in cross-section which may be correct depending on manufactuing system used. G1 continuity is inherent between a circular surface and an arbitrary surface. (Degree 2 is used because circular arcs can be represented exactly by a degree 2 rational NURBS).

FilletSrf in WIP/V7 now has the option of G2 blends in place of a circular fillets. https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/filletsrf.htm?
Updated: BlendEdge is the G2 blend equivalent of FilletEge and VariableBlendSrf is the G2 blend equivalent of VariableFilletSrf

What is acceptable or unacceptable depends on the application and preferences of the user. Unequal spacing of control point is not always inherently bad. For many engineering applications changes to the shape of a surface are very undesirable/unacceptable. For aesthetic design the changes may be fine.

Trimmed surfaces can be Rebuilt in Rhino. Rebuild works on trimmed surface, and if the Retrim option is selected then the rebuilt surface will be trimmed. RebuildUV works on trimmed surfaces but does not currently have a Retrim option, which could be added. InsertKnot and RemoveKnot can also be used on trimmed surfaces, which remain trimmed surfaces.

Yes, slightly adjusted surfaces being acceptable is definitely subjective, for sure. But realistically if you don’t have the construction data, and you don’t have the original CAD file, and you need to defeature something, you are Going to end up changing things slightly.

And yes, I misspoke. I meant to say “sometimes, you can’t rebuild a trimmed surface.” The retrim command doesn’t always work. I’m sure it’s often issues with translation, mixed tolerances from the original CAD, but Rhino only allowing a single tolerance per instance of rhino, or other various things I don’t fully understand. I mean, just to test this out, I created a cube. Exploded it and changed the surfaces all to degree 3. Then used control points to manipulate only the center CV’s to deform the box a bit so that a few of the surfaces had compound curvature.
It’s 6 surfaces. It joined fine, no naked edges. I tried BlendEdge and it failed. I filleted it all evenly and the object turned inside out and ended up with one naked edge. Explode, join again, and it’s back together. That’s Very basic example, and I already got the math to break a little. Dealing with imported CAD from solid or proE ends up being much worse.

So far this works here -


That looks great, but I see 5x the amount of surfaces to manually delete now… so how about those defeaturing tools? :stuck_out_tongue_closed_eyes:

Ooooh, so in V7, with blendEdge you can’t even do the the normal 3 sided boundary. That’s good. The only way that really Sort of works if if it’s a patch surface anyway. And those are never quite pretty.
I’d love to see the ability to control the amount they flow into the adjacent edge blend.
Anyway that’s killer. I’ll probably end up abandoning regular old fillet edge for the most part.

And yes, it Very much depends on manufacturing. If you’re dealing with Giant fillets, it really doesn’t matter. But if you’re doing an interior fillet and it’s really tight, then you’ll be limited to the cutting bit for the tool. Granted, those aren’t always balls either, so for that kind of thing, you’d likely want a more appropriate CAD modeling package that can take those sorts of things into consideration.

And yes @eobet, that was my thought as well. Although, you Do still have the same number of surfaces that you may with to extend. But realistically, if you model it in Rhino, and have all that, it’s only takes a few seconds, unless you used the Shrink command for some reason.

Explode. Delete the pieces you don’t want. UntrimAll. Join.

And if you actually have surfaces trimmed larger, you can just run CreateSolid instead.

But the point of defeature tools is more, imported data. Or data that’s been through more than just an example with a box.

Also, I like to break tools when I test them. :wink:

I didn’t text 5 pole, but it doesn’t seem to like 6 pole.

Fillets in Rhino aren’t difficult to break… and sadly, it seems that nothing much has changed, even with BlendEdge… (but these last posts belong in the Serengeti forum now)…