Rotation of a profile using the "Curve to Mesh" node in Geometry Nodes

So, I have a small hair simulation setup I imported from Houdini using an alembic Mesh Sequence Cache modifier. It is one curve object and all the points of these curves are slightly shifted:

To give them a profile I tried using Geometry Nodes' Curve to Mesh node with a curve circle as a profile curve...

...but unfortunately I can't figure out how to orient this profile so every hair profile is rotated the same way:

As far as I know the Set Curve Tilt node only tilts every hair simultaniously, so maybe there is a way using the Curve Tangent node?

I also tried to make it work using the Instance on Points node, since it has a rotation input and there was an explanation on how to use the Align Euler to vector node, but then i'd have to use cyclinders with no caps as an instance and merge their points by distance. This seemed like a dirty workaround to me and I'd rather prefer to make it work using a curve profile.

Cheers!

• Rotate the Profile Curve. Clear Curve tilt (set to 0) Commented Sep 23, 2023 at 11:59
• unfortunately rotating the profile curve will just rotate the hair as a whole but won't align the profile in one direction Commented Sep 23, 2023 at 14:21
• So you don't want to rotate all curves in the same direction, you want to align them. " so every hair profile is rotated the same way" is misleading, you don't actually want to do that. Commented Sep 23, 2023 at 14:24

Resetting the Curve Tilt to $$0$$ will not help you, because when using Curve to Mesh the tangents of the curve ultimately decide the orientation of the mesh.

So in this case you would have to correct the tilt of the individual points.

A possible solution could look like this:

(Blender 3.6+)

Or an even simpler solution might look like this:

• oh wow ! ^^' this is genius. Thank you so much for your help! Commented Sep 23, 2023 at 14:40
• Hmmm... What if you rotat each spline, so it's horizontal, and then set normal to z-up and rotate back? Commented Sep 23, 2023 at 15:47
• @MarkusvonBroady Hm, that should also work (to be honest, I haven't tested it). However, there must then never be a vertical line. Commented Sep 23, 2023 at 16:07