Realize Node in geometry node causes some faces to Flip

When I try and add a realize instance node (need to do this since object will be exported to stl to 3D print).

Based off of question. Round / smooth the end points of curve in geometry nodes

How can I prevent these faces from flipping when using the realize node?

Some of the faces are flipped see animation.


Note: I tried doing the mesh to curve and curve to mesh trick but that didn't work.

I also tried this suggestion Recalculate normals of an object using geometry nodes (it flipped more faces)

Attached file below:

  • $\begingroup$ If you want a 3D print of this object, in the end, it will have to be manifold. Would an entirely different way of modelling it be acceptable? $\endgroup$
    – Robin Betts
    Commented Dec 5, 2022 at 11:03
  • $\begingroup$ Yes, I'm always willing to learn something new. $\endgroup$
    – Rick T
    Commented Dec 5, 2022 at 12:29

1 Answer 1


They are flipping because you're turning them inside out by scaling them to $-1$. If you use a Rotate Instances instead of Scale Instances to rotate them $180º$ , they'll stay as they are:

enter image description here

I admit I hadn't noticed the behaviour that instances don't reflect what should be the correct flip orientation until they're realized. I'm not sure if that's a bug, a natural technical outcome, a performance consideration, a design choice, or overlays system failing to pick up the change or something else, though.


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