Nice… You figured out the face-corner index mapping for curve-to-mesh?
In practice, a CapMask is useful since the caps tend to be different materials (e.g. tree log).
Hope normalized face-corner UVs will be generated by curve-to-mesh out-the-box one day (for caps also) but what you did is a welcome patch for now, thanks.
Also thanks for the idea of using github for hosting node-groups.
I will be copying your homework for my Z-Curve-Sweeper node-group if that’s cool, and in return, here is a generalized curve-index-offset node-group for you:
I call it Spline Offset Index. It allows you to do delta calculations. (Blender 3.1+)
For setups that repeatedly need this node-group, it helps to separate out the accumulator section as repeated captures can be slow (you’ll see, in coming performance update to the Z-Curve-Sweeper).
Thanks.