Curves getting changed when using orient component

when I am selecting a single curve the orient compents works fine without making any changes to the curve

but when selecting multiple curves together the curves are getting changed and the planes are notproperly aligned

Seems like you have a problem with data management (lists and tree stuff).
It’s impossible to tell without looking at the definition. Can you attach it? With meaningful data internalized…

sample.3dm (5.0 MB) (19.3 KB)

This is the first problem:

You project your curve into 2 different surfaces, resulting in 2 curves.
You want to avoid that.
Move your surface profile and then make a single extrusion, a single surface.
(Also, making the surface slightly bigger than the curve should be best. Currently the curve is tangent to 2 edges of the surface. Avoid uncertainty.)

For the direction problem, add a graft on your “Evaluate Curve” here:
2021-01-14 15_33_56-Grasshopper - sample_

PS if you di Pipe after orientation of the curves, the piping function will run many times, resulting in a waste of resources/performance/time.
Do pipe before orient.

I also favor orienting one curve instead of two but making that change doesn’t fix apparent misalignment.

The two curves are not parallel, as seen in ‘Right’ view, so they have different curvature at each point.

Also not parallel in top view. And not the same length, obviously, but dividing them by length should ignore that. Why aren’t the two curves copies?

P.S. This looks much better to me? No changes except the white group, copying one curve. (19.2 KB)

P.P.S. And guess what works even better? Using just one curve instead of two!

The more I think about this, there is no correlation between either of the two curves and the extruded surface you are projecting to, so it’s a wonder that it works as well as it does with one curve.

A better approach would construct the “links” at each point along the target curve(s) instead of orienting an arbitrary link constructed on an unrelated curve (the one that is extruded).