I was modeling a Klein Bottle and end up in this type of problem after doing Solidify: simplification

I managed to remove the intersections on the Klein duplicating the surfaces and doing Boolean operations with a lot of manual deleting afterwards.

Now I am trying to find a better approach for this problem. I think the easiest solution would be to duplicate both pipes and separate them, after that doing a Intersect Boolean and a Difference in sequence; but it is not removed completely. How it is possible to fix this? after boolean

Edit: This pipe problem is a simplification of the Klein. It not about the steps to create pipes, but to fix the mesh obtained by complex XYZ Math Surface:

Section View Klein


1 Answer 1


Here is my approach from long ago, although I would do a better job with the angles now:

Klein Bottle without solidify for reference

  • Create an UV sphere.
  • Delete the top and bottom vertices.
  • Extrude a 'column' from the top into the sphere.
  • Subdivide one of the faces in the sphere enough times to create a circle.
  • Delete all of the faces inside that circle.
  • Bridge edge loops between the previous column and the new circle.
  • Bring a column around from the bottom to the same circle, by extruding and rotating.
  • Add a subsurf

If I were to do it now, I'd use a sphere with fewer slices, I would spin the turns in the columns to make them smoother and I would make the circle from several faces.

Alternatively, one could just enable Extra Objects, add an X, Y, Z Function Surface, and choose the Klein preset:

preset for a Klein surface


Klein surface generated by the presets

EDIT: If I wanted to 3D print the original, I would modify it so that it was symmetric on the XZ plane, cut it in half and print the two halves. This way you wouldn't have any extra faces to delete, although depending on the printer you would probably need some interior supports you would need to remove after printing. It would look something like this with the subsurf in place:

half a Klein Bottle

  • $\begingroup$ Pretty cool, thank you for sharing! Just tried and its pretty cool. :) My problem is after the modifiers, after the subsurf I would do a Solidify so it would be 3D printable, but removing the intersection faces manually is very bothersome. For now the best approach I found is to duplicate the mesh in the intersection on Edit Mode and do a Face: Intersect instead of a regular Boolean with objects, this way it will split the faces and is easier to select them and delete, but I think there might be a better way. How would you do it? $\endgroup$ Commented Sep 7, 2021 at 0:20
  • $\begingroup$ I think that if you subsurf the XYZ surface you won't get extra faces, but you would have to find a couple of places to slice it so that you could print it in two pieces and assemble it. I don't do 3D printing so I'm not much help though. $\endgroup$ Commented Sep 7, 2021 at 13:46
  • $\begingroup$ For now the best result I got is using the Face: Intersect (Knife), Merge by Distance and Select Linked. This way the mesh is split and much easier to delete. Doing manually like you showed is also easier to avoid intersecting geometry. Thank you ^^ $\endgroup$ Commented Sep 8, 2021 at 2:56

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