Fillet Edge opens my closed polysurface!


bezkrai.3dm (412.0 KB)
Hello!
I’m trying to fillet the edges of this solid, but when I do so, the object becomes an open polysurface. What am I doing wrong and how can I fix this?

This was tricky. Your curves weren’t nicely aligned and the figure 8 had kinks. Next problem is the self intersection which was already mentioned in another topic I think.

To resolve the self intersection you need to split the closed surface and boolean union bit by bit.

See the result. I copied your object twice so you see step by step what I did with the solid.

bezkrai.3dm (4.8 MB)

Right, @Helvetosaur seemed to have fixed your figure 8 already…

Boolean Difference keeps failing! - Rhino / Rhino for Windows - McNeel Forum

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Hi!
I trimed the unwanted surfaces and joined the others back together to create the closed polysurface.
And now without the intersection when I fillet the edges it still creates an open polysurface.
bezkrai.3dm (427.9 KB)

I see 0.3 is too big of a fillet.

0.2 works, see the file attached

bezkrai_fillet.3dm (3.5 MB)

For example I fillet the top edges and it results as open polysurfacebezkrai (2).3dm (917.6 KB)
I wanted to know why it opens the solid when I fillet its edges.

The problem you’re facing has to do with the cross sections of your sweep. Less cross sections is better and I would orient the sections perpendicular to the rail. Your base curve aslo still had a kink, which is also just going to cause trouble. I moved the point so you can see it’s a kink

Less sections, better isocurves. Compare the isocurves with your object.

bezkrai_fillet.3dm (2.9 MB)

oh i am late with my file / answer…
martinsiegrist already pointed out the most important aspects:

  • build proper curves (interal G1 oder G2 )
  • split surfaces to remove self-intersection

my approach is not to use Sweep:

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Thanks for taking your time It is still quite hard for me to do this as the final shape you got doesn’t match my preferences and when I try doing it by the steps you show me the end result is still an open polysurface. I will try Tom’s approach and see if I can pull it off.

No problem. There are a lot of details which aren’t really obvious at first… I think Tom’s approach is less problematic and you might have more control over the outcome.

Hi Tom!
I created my curves as I like them, but now I can’t quite figure out how to make the thinner line lower than the thicker one? I’m not very familiar with the loft command.

turn on control points
_pointsOn
or F10
move partial control Points with Gumball aligned to world in z-direction

Hi!
I extruded the surface, but I can’t trim the intersection surfaces. I tried creating the solid by using Sweep 2 and got the same result.krai krai.3dm (1.2 MB)

_explode … the closed Polysrf.
_delete … the surface at the bottom.
_split all 3 surfaces at the same position by isocurve, shrink = yes. pointsnap Knot.
split close to the middle of the surfaces. as the closed surface has a seam, split each surface once will result in 2x3 = 6 surfaces.
_trim
_join
_cap
_filletEdge
(send me a private message if you need paid rhino-lessons, i am based in Zürich / Switzerland)