# How to rotate a set of curves to be perpendicular to another curve (XY)?

I’m using the Pufferfish “tween through curves along curve” node, where I’ve applied a graph mapper on the range to get a different shape.

I’ve then moved them back to their “original” positions, and now I need to also rotate them “back” to be perpendicular to the original curve:

Now, I’ve used the Pufferfish “move to point” node which worked great, but then when I try to rotate, it doesn’t work as expected (I guess because I can’t set a pivot):

Anyone have any ideas for me here? Apparently the plane input actually implicitly has a pivot, so I have to calculate a unique plane per curve perhaps?

modify-tween.gh (14.4 KB)

You could do this using the standard GH Tween Curve and Orient to Perp Frames:
modify-tween.gh (11.7 KB)

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Thank you for the interesting solution… but there’s a bit of “cheating” going on there. First, you’ve moved my tween curves to the origin and aligned them in the same plane. Then you completely ignore all but the first curve’s planes. It’s clever, and I certainly learned something… can I ask two follow up questions?

• How did you color the previews of the planes differently and scale them down?
• What actually happens when you “reparameterize” the joined curves like you did? Can you divide them back in the end again and still get a line and an arc?

Now, I’d still like to learn the solution in my case as well, without moving any of my input curves… so far, I’ve got this, and I’m now trying to figure out how to rotate the highlighted planes to the projected points so I can then align the curves using those planes: