# Geo nodes. Align instanced splines tilt to instance rotation?

I instancing a bunch of splines on a curved geometry (a big pipe). Not geometry, but specifically a splines.
The problem starts when i convert those splines to mesh, because it looks like instanced splines tilt are doesnt correspond to instance rotation.

So i think it is possible to fix by setting the appropriate curve tils for each instance, but i dot really get how to calculate those angle?

can u pls provide blend file or node tree? thx

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Hereâ€™s the problem:
Until we realize instances, the tilt of curve (or tilt/rotation of Arc node) are perfectly fine. For make it more clear i set angle to less than 360 degree so we can clearly see - its align perfectly.

Unfortunately, in the moment we realize intances, curves tilt (or Arc tilt?) will be ruined:
Notice how some of the Arc rotated in the wrong direction (if we rotate initial mesh (â€śdonutâ€ť) Arc (or curves tilt?) will become even more random and unpredictable:

For a reason i want to keep Arc orientation in the correct way without unwanted random rotations.
I also need this to being able to add random noise which will be unique for all spines, so i need to realize them anyway before converting them to mesh.

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Oh manâ€¦ I donâ€™t think youâ€™re going to like the answerâ€¦

â€¦basically you have to make an instance with Geometry to Instance, make as many copies as you need with Duplicate Elements in Instance modeâ€¦ realize that then do what you wanna do with them (noise, curve-to-mesh, etc.) at the origin and then use the Duplicate Index as input to a Sample Index to read the curve data to then do a Set Positionâ€¦

It completely breaks the convenience of using instances in the first place but I donâ€™t know of a more convenient workaround. Sorry.

Hope that helps.

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I was thinking exactly in that way, i.e. creating a duplicates and place them where i need, but have no idea how to achieve that (even wasnt sure its possible with duplicated geo).
Many thanks!

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