Grasshopper - Arrayed Curves on surface at specified distance parallel to existing line

Welcom to the forum.

Please see this (click the link and read the whole post):

In particular, pay attention to Item #3:

3. Attach minimal versions of all the relevant files
If you have a gh file you have a question about, attach it to the post. Do not expect that people will recreate a file based on a screen-shot because that’s a lot of pointless work. It’s also a good idea to remove everything non-essential from a gh file.

If you attach a file, you are likely to get a response with that file updated to include the solution to your question.

As far as your current question, perhaps the Contour component?

Or perhaps you could extract edges, divide, and create lines.

-Kevin