How to construct surface (where fillet fails)?


I ran into a problem with a model I’m currently working on, where Filet Edge deletes some faces of my solid. Now, I know that this is nothing special in Rhino, but I’m having trouble constructing the filet by hand.
Here’s the part of the model that gives me headaches:

I’ve tried sweeping with two rails, but couldn’t really get it to work nicely. Lofting is not really an option since it produces a straight slope, and I want it to look like the rest of the filets.

What would be a better strategy for this case?


filet_fail.3dm (5.1 MB) [Rhino 6 file]

take a look of some examples like this:

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Hi @p1r4t3b0y

I had a quick look over your model, I’m not 100% sure what you are trying to achieve.
What exactly about the 2rails did not meet your expectation?

I’ve uploaded the file for what I would have thought you wanted with the 2rails, were you getting a different result?

filet_fail Edited_v1.3dm (2.0 MB)

Sry I don’t have a Mac, so I hope this isn’t a Mac only issue.

Also I reckon this straight line might have caused your fillets disappearing, as the radius would have been interrupted when filleting, as it was too big for the surface.


First of all, thanks for your replies @DiegoKrause and @nicholasm785!

Exactly what you show above! I’m pretty tired, since I’ve worked all day, and I must have overlooked that one of my cross section curves was off. My original file is pretty messy with lots of curves, even duplicate ones. Rookie mistake… :flushed:

Don’t worry! These days Mac and Windows Rhino are pretty similar in terms of core functionality.
I don’t get why they don’t do a general Rhino discussion forum, and only Windows and Mac categories for things like bug reporting.

Good to know. Thanks for pointing that out!

Glad I could help @p1r4t3b0y.

Just to let you know, I used the rebuild cross sections option on the 2rails to make it a bit cleaner.

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OK, do you also end up with an open polysurface, when you join the surfaces? Would you know how to fix that? I need to get back to a solid/closed polysurface.

You had 2 ‘bad objects’ on each end that I had to remake, also 4 fillets (also highlighted).
I remade that and joined it together.

The only naked edges lefts are the ones I got with the original files on the other corners.

Have a go at remaking these, if you’re lucky just explode the model and mirror the missing faces from the rebuilt corner.

Hope this helps :smiley:

So sorry forgot to upload the file.
filet_fail Edited_v2.3dm (1.7 MB)
Edit:[getting a bit late I think]

Thank you, @nicholasm785, for staying up late to help me and your tremendous shared insights. Have a nice Sunday!

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