Tricky fillet

Hi . I would like to ask for an advice regarding of how to fillet the uploaded geometry (I marked the edges in red). The outcome so far is to have a hole in between that I could patch …but becomes a little bit messy for the eye. I am wondering if is it possible to fillet so many edges at different angles…and preserve a seamless transition. If not I guess I will need to leave air in between the modules…and make them merge with a flat surface instead to do it between them.

Thanks so much

tricky fillet.3dm (3.9 MB)

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This requires set back fillets. I wouldn’t even attempt do this manually in Rhino. It would take at least an hour to do all the splits and trims. Before getting a wonky fill result with Rhino’s patch command. In the end no matter the cad modeler the results will not look great. This sort of thing, no matter the cad modeler is not going to look good. k7

I was thinking converting it to polygons. It comes from grasshopper…

Or you could rework the form to easily fillet. With the benefit of looking better in it’s finished state.

can i ask what you suggest?

What areas/dimensions if any, can’t be messed with? Does it have a function?

Hello - something like this is how I’d do this with fillets.

tricky fillet_PG.3dm (198.1 KB)


This is just outstanding. I placed next to the geometry without fillets. I am trying to find the step by step way you made this. I would like to understand the logic in order to tackle feature issues. Can I upload a screen shot in order you explain to me (if possible) how did you find the curves? Thanks a lot

Hi Bruno - the logic is really to proceed surface by surface (FilletSrf command) - it can be tricky to see that some of the required fillets are between the starting surfaces and some of the fillets that you create, or between fillets. I’ll post a more detailed file in a bit here…

@Bruno_Suraski - here’s a set of steps.

tricky fillet_Steps.3dm (504.8 KB)



Thanks so much for the insights I really appreciate it!!

Hi Pascal. I can’t generate the fillet surface in blue. FilletSrf doesn’t work for me. Some idea?
Thank you.


tricky fillet-3.3dm (4.4 MB)
Been chipping away at this in my spare time. Took about a day in all but I was wondering how quickly someone who uses Rhino day-in day-out could do it?

@ Stratosfear
the same problem is discussed here:
as “Mitch’s Second Fillet Challenge”
but the initial post is a bit different - maybe interpreted the screenshot wrong.