What to do when FilletEdge turns a closed solid polysurface into an open one?

example.3dm (1.0 MB)

Take a situation like this, where a very basic 3D form was constructed through a quick-and-dirty “sketching” process of running boolean intersections/differences on various solids, trimming away some garbage, and then joining everything together into a nice watertight closed solid polysurface (checked: no naked edges).

Running a FilletEdge on certain areas clearly “fails” in that it sort of rebreaks the entire solid, and it only fillets two surfaces together. The top and bottom surfaces are left untouched, and there are 2 clear gaps now at the top and bottom.

I get an intuitive sense at this point of why this is probably not working as I want it to (because of the steps I took to get here), but nevertheless, if my goal is to just generate fast concepts — and you hit a moment like this where you want a nice rounded filleted edge… what do you do? What’s the easiest / most effective thing to do?

yes, this is how fillet works in rhino
a trick would be to extract the blue surfaces
extend them a little
create the fillet between the green surfaces
extend the resulting fillet surfaces
and finally trim and join

example.3dm (2.0 MB)

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…sigh. Brutal.

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This is all about strategy, the order in which you do things, and avoiding having any tangent edges anywhere near Booleans, as that often leads to pain.
Avoid having multi-surface joints anywhere near where you want to run a fillet, and if possible run the fillet on the subtracted geometry first.

Strategy.3dm (235.3 KB)

In a scenario where one is simply rapidly conceptualizing a form in a less strategic sequence (as I did), then I suppose the only option is to then refactor/resurface things as you did!

I’d really love to know more about how you actually did remove the “joints” between all of the surfaces and what steps you took above. The screenshot makes it seem like you created some massive loft (but from what source curves — your own?), but then what?

Thank you!

I think I just untrimmed your surfaces, but sorry have to sleep now. I’ll take a look tomorrow…

Ye, on this one. The original surface without the additional unnecessary edges works great.

Still not really sure where the extra edges came from. But the first surface that was modeled looks super nice.

Having some fun with it:

when your input curves has already filleted corners is common that you will obtain a single surface using loft or extrude

removing joints in this case has to do with using the Untrim command to get to the original full surface that was modeled.

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Gotcha — thought I had shrunk the surfaces somehow and didn’t think of untrimming to return the original master surface.

Still curious how cairn then recut the master surface back down to match the design afterwards! Will wait for his passing slumber. :wink:

The original surface is always there, no matter how many times it is trimmed. This is also true if it is periodic.

But Shrink trimmed surface command can change a single surface that is underlying a trim. It is one of the reasons to be careful with shrink trimmed.


similar method


I did pretty much what @DiegoKrause did in the video… :slightly_smiling_face:

@DiegoKrause What screen capture are you using for that vid? :grinning:

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…ah, not free… (shrugs) :joy:

you can use Filmora9 which is pretty similar and free or Camstudio which is only to record the screen not to edit later


Ah cool, thanks man :slight_smile:

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take a Look to OBS studio, for me it works very well and is Opensource multiplatform.

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Yes I use it too but for streaming only, and still need a platform to make some adjustments later, that’s why I use Camtasia