We are trying to extract a worldspace normal from curves.
The final idea is to use the curves direction to drive a vector motion in nuke.
So a vertical (y) curve would gives a full green value (0,1,0), horizontal (x) one a red value (1,0,0), and Z.
I am honestly struggling on the math parts so any help from you would be welcome
I will keep you updated if I end up with something,
Have a nice day,
H